Solution and method for preventing and controlling postharvest grain fungal diseases

Abstract

The invention discloses a solution and a method for preventing and controlling fungal diseases of postharvest grains, and belongs to the technical field of postharvest preservation of agricultural products. Benzyl isothiocyanate is used for volatile treatment of harvested grains in a closed environment, bacteriostasis is achieved through the characteristic that benzyl isothiocyanate destroys the integrity of cell membranes of pathogenic bacteria, the occurrence rate of fungal diseases is greatly reduced, a disease-resistant enzyme system of the grains is activated, benzyl isothiocyanate is applied to postharvest storage of the grains, growth of the pathogenic bacteria can be effectively inhibited, and the disease-resistant enzyme system of the grains is activated. And the method has an important effect on prevention and control of harmful microorganisms after grain harvesting. The method is suitable for storage and preservation of tuber and cereal grains, and is green, safe and free of chemical residues.

Description

Technical Field

[0001] This invention belongs to the field of postharvest preservation technology for agricultural products, specifically relating to methods for controlling postharvest fungal diseases in grains, as well as the preparation of solutions, capsules, and their encapsulation processes. Background Technology

[0002] Postharvest fungal diseases are a core factor contributing to global food storage losses. According to a 2021 report by the Food and Agriculture Organization of the United Nations (FAO), food losses in developing countries due to deficiencies in postharvest management amount to 20% to 40% (an average loss rate of 23% for cereals and 35% for tubers), with fungal rot contributing more than 50% of these losses.

[0003] Currently, the use of fungicides and synthetic chemicals is an important means of controlling post-harvest diseases in grains. However, the conventional method of using chemicals to control post-harvest degradation has become a concern. Furthermore, synthetic fungicides have side effects on humans, and long-term use may lead to the development of fungicide-resistant pathogens. Therefore, developing effective antibacterial and environmentally friendly post-harvest preservation methods for agricultural products has become an urgent need in the grain storage field. Summary of the Invention

[0004] In view of at least one of the above technical problems, the present invention uses benzyl isothiocyanate as a postharvest fungal control and preservation agent for grains. It utilizes its volatile properties to control fungal diseases in postharvest storage of grain crops. Simultaneously, by leveraging the broad-spectrum antibacterial activity, low mammalian toxicity, and easy degradation properties of benzyl isothiocyanate, it solves the technical problems of low pesticide control efficiency and residual pollution. The specific technical solution is as follows: A solution for controlling postharvest fungal diseases in grains is prepared by diluting a standard solution of benzyl isothiocyanate with 0.1% Tween 80 and then ultrasonically emulsifying it. The ultrasonic emulsification time is 30 min and the ultrasonic frequency is 40 kHz.

[0005] A release carrier for controlling postharvest fungal diseases in grains includes an adsorption carrier, wherein the adsorption carrier adsorbs the aforementioned solution for controlling postharvest fungal diseases in grains.

[0006] A method for controlling postharvest fungal diseases in grains involves placing the postharvest grains in a sealed space, with the aforementioned release carrier placed inside the sealed space. The postharvest grains are then fumigated with benzyl isothiocyanate volatilized by the release carrier to inhibit fungal diseases.

[0007] In some embodiments of this disclosure, the concentration of benzyl isothiocyanate used for fumigation ranges from 30 to 500 μM / Lair, and the fumigation temperature is 28°C.

[0008] A microcapsule powder for controlling postharvest fungal diseases in grains, with a wall material of 5% hydroxypropyl-β-cyclodextrin and a core material of benzyl isothiocyanate standard solution, a molar ratio of core wall to core material of 3:1, and an encapsulation efficiency of >70%.

[0009] A method for preparing microcapsule powder for controlling postharvest fungal diseases in grains, comprising the following steps: preparing 5% hydroxypropyl-β-cyclodextrin, stirring at room temperature for 30 minutes with a magnetic stirrer; adding Tween 80 to the hydroxypropyl-β-cyclodextrin at a target concentration of 1%, continuing stirring until fully dissolved to form a homogeneous system; adding benzyl isothiocyanate standard solution dropwise at a ratio of 1:3; stirring and premixing; ultrasonicating the mixed solution to promote the inclusion of BITC with cyclodextrin using the cavitation effect; centrifuging, filtering, and freeze-drying the obtained emulsion to obtain the microcapsule powder.

[0010] A method for controlling postharvest grain fungal diseases involves dissolving the aforementioned microcapsule powder in water and spraying it into a sealed space, or placing the aforementioned microcapsule powder in a breathable container and then placing it into a sealed space, thereby fumigating the postharvest grain with the released benzyl isothiocyanate to inhibit fungal diseases.

[0011] In some embodiments of this disclosure, the postharvest food includes tuber foods and / or cereals.

[0012] In some embodiments of this disclosure, the fungal disease includes at least one of *Fusarium solani*, *Fusarium solani*, or *Aspergillus flavus*.

[0013] Compared with existing technologies, the above-mentioned solution and method for controlling postharvest fungal diseases in grains have the following beneficial effects: This invention applies benzyl isothiocyanate to postharvest storage of grain, which can effectively inhibit the growth of pathogens and reduce the spread of pathogens, playing an important role in the postharvest control of harmful microorganisms in grain. This invention utilizes the volatility of benzyl isothiocyanate to treat postharvest grains in a closed environment. By disrupting the cell membrane integrity of pathogens, it achieves antibacterial effects, significantly reducing the incidence of fungal diseases and activating the grain's own disease-resistant enzyme system. This invention is applicable to the storage and preservation of tuberous and cereal grains. It is green, safe, and free of chemical residues, providing new technical insights for the prevention and control of postharvest fungal diseases in grains. Attached Figure Description

[0014] Figure 1 This is a schematic diagram illustrating the antibacterial effect of benzyl isothiocyanate in this invention; where horizontal region A represents *Saccharomyces cerevisiae*, horizontal region B represents *Fusarium*, and horizontal region C represents *Aspergillus flavus*.

[0015] Figure 2This is a schematic diagram illustrating the growth inhibition effect of benzyl isothiocyanate on the germination of sweet potato spores in this invention.

[0016] Figure 3 This is a schematic diagram illustrating the growth-inhibiting effect of benzyl isothiocyanate on the germination of Fusarium solani spores in this invention.

[0017] Figure 4 This invention relates to the effect of benzyl isothiocyanate on the accumulation of reactive oxygen species in the mycelium of *Saccharomyces cerevisiae*.

[0018] Figure 5 This invention relates to the effect of benzyl isothiocyanate on the accumulation of reactive oxygen species in Fusarium solani mycelia.

[0019] Figure 6 This invention relates to the postharvest effect of benzyl isothiocyanate on sweet potato.

[0020] Figure 7 This invention relates to the effect of benzyl isothiocyanate on the activity of superoxide dismutase in postharvest sweet potato.

[0021] Figure 8 This invention relates to the effect of benzyl isothiocyanate on postharvest sweet potato peroxidase activity.

[0022] Figure 9 This invention relates to the effect of benzyl isothiocyanate on the activity of postharvest sweet potato polyphenol oxidase.

[0023] Figure 10 This invention relates to the effect of benzyl isothiocyanate on the activity of postharvest sweet potato phenylalanine ammonia-lyase.

[0024] Figure 11 This invention relates to the effect of benzyl isothiocyanate on the vitamin C content of postharvest sweet potatoes.

[0025] Figure 12 The effect of benzyl isothiocyanate on the proline content of postharvest sweet potato in this invention.

[0026] Figure 13 This invention demonstrates the inhibitory effect of benzyl isothiocyanate on sweet potato black spot disease.

[0027] Figure 14 This is a schematic diagram illustrating the effect of benzyl isothiocyanate on the diameter of sweet potato black spot lesions in this invention.

[0028] Figure 15 This is a schematic diagram illustrating the changes in superoxide dismutase activity during the control of postharvest black spot disease in sweet potatoes using benzyl isothiocyanate in this invention.

[0029] Figure 16 This is a schematic diagram illustrating the changes in peroxidase activity during the control of postharvest black spot disease in sweet potatoes using benzyl isothiocyanate in this invention.

[0030] Figure 17 This is a schematic diagram illustrating the changes in the activity of sweet potato polyphenol oxidase during the control of postharvest black spot disease by benzyl isothiocyanate in this invention.

[0031] Figure 18 This is a schematic diagram of sweet potato phenylalanine ammonia-lyase during the control of postharvest black spot disease by benzyl isothiocyanate in this invention.

[0032] Figure 19 This is a schematic diagram illustrating the changes in vitamin C content in sweet potatoes during the control of postharvest black spot disease using benzyl isothiocyanate in this invention.

[0033] Figure 20 This is a schematic diagram illustrating the changes in proline content in sweet potatoes during the control of postharvest black spot disease using benzyl isothiocyanate in this invention.

[0034] Figure 21 This is a schematic diagram of the benzyl isothiocyanate embedding process in this invention; wherein, A is the sample after embedding but not freeze-dried; B is a schematic diagram of the BITC standard curve; and C is a schematic diagram of the scanning electron microscopy detection results of the sample after freeze-drying. Detailed Implementation

[0035] To better understand the purpose, structure, and function of this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below. It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit this application.

[0036] As shown in the attached diagram. Figures 1 to 21 As shown, a solution for controlling postharvest fungal diseases in grains was designed. It was prepared by diluting a standard solution of benzyl isothiocyanate (BITC) with 0.1% Tween 80 and then ultrasonically emulsifying it. The ultrasonic emulsification time was 30 min and the ultrasonic frequency was 40 kHz.

[0037] A release carrier for controlling postharvest fungal diseases in grains includes an adsorption carrier that adsorbs the aforementioned solution for controlling postharvest fungal diseases in grains. Further optimization could be achieved by using filter paper that has been sterilized and dried at high temperatures as the adsorption carrier.

[0038] A method for controlling postharvest fungal diseases in grains involves placing the harvested grains in a sealed space, with a release carrier (as described above) placed inside. The grains are then fumigated with benzyl isothiocyanate (BITC) released from the carrier to inhibit fungal diseases. The fumigation concentration of BITC is MIC and 2MIC, with the benzyl isothiocyanate concentration ranging from 30 to 500 μM / L air. The fumigation temperature is 28°C.

[0039] A microcapsule powder for controlling postharvest fungal diseases in grains, with a wall material of 5% hydroxypropyl-β-cyclodextrin and a core material of benzyl isothiocyanate standard solution (BITC), a core-to-core material molar ratio of 3:1, and an encapsulation efficiency >70%.

[0040] A method for preparing microcapsule powder for controlling postharvest fungal diseases in grains, comprising the following steps: preparing a 5% concentration of hydroxypropyl-β-cyclodextrin solution, stirring at room temperature for 30 minutes using a magnetic stirrer; adding Tween 80 to the hydroxypropyl-β-cyclodextrin at a target concentration of 1%, and continuing stirring until fully dissolved to form a homogeneous system; adding benzyl isothiocyanate standard solution (BITC) dropwise at a ratio of 1:3, stirring and premixing; then sonicating the mixture to promote the inclusion of BITC and cyclodextrin using cavitation effect; and centrifuging, filtering, and freeze-drying the resulting emulsion to obtain the microcapsule powder. This encapsulation process helps to mitigate the rapid volatilization of BITC during application and helps to enhance its water solubility and sustained-release effect.

[0041] A method for controlling postharvest fungal diseases in grains involves dissolving the aforementioned microcapsule powder in water and spraying it into a sealed space, or placing the microcapsule powder in a breathable container and then placing it into a sealed space. The released benzyl isothiocyanate is then used to fumigate the postharvest grains to inhibit fungal diseases. The postharvest grains include tuberous crops and / or cereals; the fungal diseases include *Streptococcus longifolius* (…). Ceratocystis fimbriata , C. fimbriata Fusarium solani () Fusarium solani , F. solani ) or Aspergillus flavus ( Aspergillus flavus , A. flavus At least one of the following.

[0042] This invention belongs to the field of postharvest preservation technology for agricultural products, specifically relating to a method for using benzyl isothiocyanate (BITC), a plant-derived active substance, in the control of postharvest fungal diseases. It is applicable to the storage and preservation of tuberous crops (such as sweet potatoes and potatoes) and cereal grains. This invention utilizes the volatility of benzyl isothiocyanate in a sealed environment to treat postharvest grains. By disrupting the cell membrane integrity of pathogens, it achieves antibacterial activity, significantly reducing the incidence of fungal diseases and activating the grain's own disease-resistant enzyme system. Applying benzyl isothiocyanate to postharvest grain storage effectively inhibits pathogen growth and reduces the spread of pathogens, playing a crucial role in the postharvest control of harmful microorganisms in grains. This invention leverages the volatile nature of benzyl isothiocyanate, avoiding direct contact with grains during disease control, making it suitable for the storage and preservation of tuberous and cereal grains. It is green, safe, and leaves no chemical residues.

[0043] Benzyl isothiocyanate (BITC) is a major active ingredient in papaya seed oil, maca volatile oil, and other similar products; it is also known as benzyl mustard oil. According to filings with the National Institutes of Health (NIH) and the NCBI PubChem Project (PubChemCID: 2346), BITC is widely used as a food improver in the food industry. Furthermore, it possesses broad-spectrum antibacterial properties, low mammalian toxicity, and is readily degradable, meeting the requirements for green and safe products and serving as a natural antibacterial agent.

[0044] Benzyl isothiocyanate plays an important role in the control of fungal diseases in grains, enhancing its application value and providing a new means of controlling fungal diseases during grain storage.

[0045] The relevant experiments are as follows: Experiment I: Verification of the universal antibacterial properties of benzyl isothiocyanate Take freshly cultured mycelium plates, rinse with Tween 20, filter to obtain spore solution, count the spores under an optical microscope and calculate the concentration of the spore solution, then dilute the spore solution to 10. 6 / mL for use. Minimum inhibitory concentration (MIC): The experiment was conducted in 96-well plates, with a final system of 200 μL per well, containing 170 μL of PDB medium, 20 μL of spore suspension, and 10 μL of drug. Premixed solutions were prepared based on the final system, mixed thoroughly, and dispensed into 96-well plates. Then, 10 μL of drug solution was added to each well to achieve final concentrations of 0, 3.75, 7.5 μM, 15, 30, 60, 120, 240, 480, 960 μM and 0, 0.015, 0.03, 0.06, 0.12, 0.24, 0.48, 0.96, 1.92, 3.84 mM. Each concentration group was replicated twice. After sealing with sealing film, the plates were incubated at 28°C for 7 days. Results are as follows. Figure 1 As shown, benzyl isothiocyanate has good antifungal effects against a variety of pathogenic fungi: benzyl isothiocyanate has a good antifungal effect against *Saccharomyces cerevisiae* (Saccharomyces cerevisiae). C. fimbriata The minimum inhibitory concentration (MIC) is 30 μM (e.g. Figure 1 As shown in A), against Fusarium solani (… F. solani The minimum inhibitory concentration (MIC) is 0.12 Mm (e.g. Figure 1 As shown in B), for Aspergillus flavus ( A. flavus The minimum inhibitory concentration (MIC) is 0.24 mM (e.g., Figure 1 (as shown in C).

[0046] Experiment II: Inhibitory effect of benzyl isothiocyanate on the growth of pathogenic fungi This study primarily used *Saccharomyces cerevisiae* and *Fusarium solani* as examples, examining the effects of benzyl isothiocyanate on colony diameter and spore germination. The specific steps are as follows: (1) Effect of benzyl isothiocyanate on the germination of pathogenic fungal spores: The spore suspension of the pathogenic fungus was inoculated into 20 mL of PDB medium and different concentrations of BITC were added. The mixture was cultured at 28℃ and 180 rpm for 9 h. The germination rate of sweet potato long-beaked spores after treatment with different concentrations of BITC was observed under a microscope. Each treatment group had three replicates. Figure 2 and Figure 3 The spore germination experiment results showed that spores without BITC germinated well, and the spore germination rate gradually decreased with the increase of benzyl isothiocyanate concentration.

[0047] (2) Effect of benzyl isothiocyanate on the growth diameter of pathogenic fungi: The prepared bacterial solution was inoculated on PDA plates containing different concentrations of benzyl isothiocyanate and placed in a 28℃ incubator for 7 days. The colony diameter was then measured and recorded. Each treatment group had three replicates. Figure 4 and Figure 5 The experimental results more intuitively show that when the BITC concentration reaches 15 μM and 0.12 mM, the colony diameter of sweet potato scab and Fusarium rotundum is significantly inhibited, while at 60 μM and 0.24 mM, the two pathogens do not grow at all on PDA plates.

[0048] Experiment III: Effect of benzyl isothiocyanate on the accumulation of reactive oxygen species in fungal hyphae Taking *Polygonum longifolium* and *Fusarium solani* as examples, the effect of benzyl isothiocyanate on the accumulation of reactive oxygen species in the mycelia of pathogenic fungi was detected, and the following steps were followed: Spore suspensions of the pathogenic fungus were inoculated into 20 mL of PDB medium and cultured at 28℃ and 180 rpm until mycelial morphology was achieved. Then, different concentrations of BITC were added to the cultured mycelia for 4 h. The mycelia were centrifuged at 6000 rpm to remove the medium, and then washed twice with PBS. After treatment, the samples were centrifuged at 12000 rpm for 5 min, the supernatant was collected, and the bacterial suspension was resuspended after eluting with PBS buffer 2-3 times. The samples were then treated with a reactive oxygen species (ROS) kit for 30 min. After treatment, the samples were centrifuged under the same conditions, the supernatant was discarded, and the samples were resuspended after eluting 2-3 times. Finally, the samples were observed under a fluorescence microscope. The results are as follows: Figure 5 As shown, the green fluorescence of the BITC-treated samples increased compared to the untreated samples, indicating that BITC treatment leads to an increase in ROS content in the mycelia of *Fusarium solani* and *Fusarium solani*.

[0049] Experiment IV: Effects of benzyl isothiocyanate on postharvest grain crops and related resistance enzyme activities Using sweet potato as the main crop, the activity of benzyl isothiocyanate against several sweet potato resistance enzymes was determined. The specific steps are as follows: (1) Pretreatment of sweet potato samples: Fresh sweet potatoes were rinsed with running water and then dried. They were disinfected with 2% v / v sodium hypochlorite solution, rinsed with sterile water and dried, and then made into 2 cm potato chips with sterile knives. (2) Fumigation with benzyl isothiocyanate: Prepare filter paper containing different concentrations of benzyl isothiocyanate so that the concentrations released in the sealed space are 0, 7.5, 15, 30, and 60 μM / L air, respectively. Place the sweet potato sample in a sterile lunch box containing filter paper containing different concentrations of benzyl isothiocyanate and fumigate at 28°C.

[0050] (3) Enzyme activity detection of sweet potato samples: The fumigated sweet potatoes were ground in liquid nitrogen, and then the corresponding kits were used to detect the enzyme activity of the sweet potato samples. The results are as follows: Figures 6 to 12 As shown, the phenotype of sweet potato samples did not change significantly after fumigation with benzyl isothiocyanate, and the activities of related resistance enzymes increased, which is beneficial for preventing the invasion of pathogenic microorganisms during the storage of post-harvest sweet potatoes.

[0051] Experiment V: Effects of benzyl isothiocyanate on postharvest grain diseases This study focused on sweet potatoes susceptible to black rot, and determined the enzyme activity of resistance enzymes in sweet potato samples inoculated with *Saccharomyces cerevisiae*. The specific steps are as follows: (1) The sweet potato sample pretreatment is the same as step (1) in Experiment IV.

[0052] (2) Inoculation of sweet potato samples with *Saccharomyces cerevisiae*: Pretreated sweet potatoes were perforated with a sterile punch, and then 10 μL of spore suspension was inoculated into each sample at a concentration of 1*10 μL. 6 spores / mL.

[0053] (3) The fumigation steps for benzyl isothiocyanate are the same as those in step (2) of Experiment IV.

[0054] (4) Determination of the diameter of black spot spread in sweet potato samples: The black spot on the fumigated sweet potato samples was measured and recorded, and the results are as follows: Figure 13 and Figure 14 As shown, the degree of inhibition against sweet potato black spot disease gradually increases with the increase of BITC fumigation concentration. Fumigation at a concentration of 30 μM / L air can significantly inhibit the spread of sweet potato black spot disease, while fumigation at a concentration of 60 μM / L air can completely control the spread of sweet potato black spot disease on sweet potato samples.

[0055] (5) The steps for detecting enzyme activity in sweet potato samples are the same as step (3) in Experiment IV. The results are as follows: Figures 15 to 20 As shown, the activity of resistant enzymes was significantly increased in sweet potato samples inoculated with only *Hemiberle spicata* compared to untreated samples. However, the activity of resistant enzymes decreased in sweet potato samples inoculated with *Hemiberle spicata* and then fumigated with benzyl isothiocyanate compared to those inoculated with only *Hemiberle spicata*, but still increased compared to untreated samples. This indicates that fumigation with benzyl isothiocyanate not only inhibits the infection of *Hemiberle spicata*, but also increases the activity of resistant enzymes in sweet potato samples, enabling them to resist the spread of sweet potato black rot.

[0056] Experiment VI: Preparation process of benzyl isothiocyanate microcapsules Prepare a 5% hydroxypropyl-β-cyclodextrin (HP-β-CD) solution and stir at room temperature for 30 min using a magnetic stirrer. Then, add Tween 80 to the HP-β-CD solution at a target concentration of 1% and continue stirring for 15 min to ensure complete dissolution and a homogeneous system. Slowly add BITC dropwise to the cyclodextrin solution containing Tween 80 at a ratio of 1:3 and continue stirring (e.g., 500 rpm, 30 min) for premixing. Then, sonicate the mixture (40 kHz, 300 W, 20 min) to promote the inclusion of BITC and cyclodextrin using cavitation. The resulting emulsion is shown below. Figure 21 As shown. Finally, the obtained emulsion was centrifuged, filtered, and freeze-dried to obtain microcapsule powder. 0.1 g of the freeze-dried sample was weighed, dissolved in 1 mL of chromatographic grade methanol, sonicated, filtered through a 0.22 μm sterile filter membrane, and detected by high-performance liquid chromatography. The concentration of the sample is shown in Table 1 below, and the encapsulation rate is high. Observations of cyclodextrin and cyclodextrin-encapsulated samples at different magnifications revealed that the surface of the BITC-encapsulated sample formed a porous structure, such as... Figure 21 As shown in section C, this indicates that the inclusion was successful.

[0057] Table 1 Encapsulation efficiency of BITC essential oil microcapsules

[0058] In summary, this invention relates to the control of postharvest diseases in grain crops by benzyl isothiocyanate, a natural active substance, and provides a novel and efficient technology for the control of postharvest diseases in grain crops. Benzyl isothiocyanate is being applied for the first time in the field of postharvest fungal disease control in grain crops; this method is green, safe, and efficient while reducing chemical pesticide residues and pollution.

[0059] It is understood that the above description is only for illustrating specific embodiments of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions within the technical scope disclosed in this application should be covered within the scope of disclosure of this application.

Claims

1. A solution for controlling postharvest fungal diseases in grains, characterized in that, The benzyl isothiocyanate standard solution was diluted with 0.1% Tween 80 and then ultrasonically emulsified. The ultrasonic emulsification time was 30 min and the ultrasonic frequency was 40 kHz.

2. A release carrier for controlling postharvest fungal diseases in grains, characterized in that, It includes an adsorption carrier that adsorbs the solution of claim 1 for controlling postharvest fungal diseases in grains.

3. The release carrier for controlling postharvest fungal diseases in grains according to claim 2, characterized in that, The adsorption carrier is filter paper that has been sterilized and dried at high temperature.

4. A method for controlling postharvest fungal diseases in grains, characterized in that: The harvested grain is placed in a sealed space, and the release carrier described in claim 2 is placed inside the sealed space. The benzyl isothiocyanate volatilized by the release carrier is used to fumigate the harvested grain to inhibit fungal diseases.

5. The method for controlling postharvest fungal diseases in grains according to claim 4, characterized in that, The concentration of benzyl isothiocyanate used for fumigation ranges from 30 to 500 μM / L air, and the fumigation temperature is 28℃.

6. A microcapsule powder for controlling postharvest fungal diseases in grains, characterized in that, The wall material is 5% hydroxypropyl-β-cyclodextrin, the core material is benzyl isothiocyanate standard solution, the molar ratio of core wall to core material is 3:1, and the encapsulation efficiency is >70%.

7. A method for preparing microcapsule powder for controlling postharvest fungal diseases in grains, characterized in that, The specific steps for preparing the microcapsule powder according to claim 6 are as follows: Prepare a 5% concentration of hydroxypropyl-β-cyclodextrin solution, stir at room temperature for 30 minutes using a magnetic stirrer, add Tween 80 to the hydroxypropyl-β-cyclodextrin at a target concentration of 1%, continue stirring until fully dissolved to form a homogeneous system, add a benzyl isothiocyanate standard solution dropwise at a ratio of 1:3, stir and premix, then sonicate the mixed solution to promote the inclusion of BITC with cyclodextrin using the cavitation effect, centrifuge, filter, and freeze-dry the obtained emulsion to obtain the microcapsule powder.

8. A method for controlling postharvest fungal diseases in grains, characterized in that: The microcapsule powder of claim 6 is dissolved in water and sprayed into a sealed space, or the microcapsule powder of claim 6 is placed in a breathable container and then placed into a sealed space, and the released benzyl isothiocyanate is used to fumigate postharvest grains to inhibit fungal diseases.

9. The method for controlling postharvest fungal diseases in grains according to claim 4 or 8, characterized in that, The postharvest food includes tuber foods and / or grains.

10. The method for controlling postharvest fungal diseases in grains according to claim 4 or 8, characterized in that, The fungal diseases include at least one of the following: *Fusarium solani*, *Fusarium solani*, or *Aspergillus flavus*.

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