A wasabi insect repellent, its preparation method and application

Abstract

This invention provides a wasabi insect repellent, its preparation method, and its application, belonging to the technical field of plant-derived insect repellents. The wasabi insect repellent of this invention uses wasabi as raw material. After washing, drying, and cell wall disruption, it is extracted under a high-voltage pulsed electric field and treated with ultrasound to obtain an extract and wasabi residue. The extract is then adsorbed and encapsulated by a composite carrier composed of diatomaceous earth, β-cyclodextrin, and zein to obtain an encapsulated wasabi compound. The wasabi residue is enzymatically hydrolyzed by a composite enzyme to obtain an enzymatic hydrolysate. The encapsulated compound and the enzymatic hydrolysate are mixed to obtain the wasabi insect repellent. The preparation method of this invention achieves high-value utilization of wasabi leaves, fully releasing and protecting the insecticidal active ingredients. The wasabi insect repellent of this invention can prolong the initial appearance time of mold and improve the repellency and antifeeding rate against stored grain pests.

Description

Technical Field

[0001] This invention belongs to the field of plant-derived insect repellent technology, and particularly relates to a wasabi insect repellent, its preparation method, and its application. Background Technology

[0002] Wasabi, also known as mountain purslane, is a perennial herbaceous plant belonging to the Brassicaceae family. Its underground tubers, when crushed, produce isothiocyanates that impart a unique pungent flavor, making it an important condiment in traditional Japanese cuisine, such as raw seafood and sashimi. However, the edible and economic value of wasabi has long been highly concentrated in its tubers, which presents significant limitations: the long growth cycle and strict harvesting period of the tubers result in limited production capacity and high costs.

[0003] Meanwhile, the above-ground parts of wasabi—especially the leaves—are often discarded as agricultural by-products after harvesting, failing to be effectively utilized. Although wasabi leaves are rich in flavonoids and other bioactive components, and possess the advantages of large biomass and readily available harvesting, their coarse fibers, significant astringency, and strong pungent flavor make them unpalatable for direct consumption, severely limiting their development and application in the high-value food sector. Currently, there are no clear reports on the effects of wasabi leaves in inhibiting microbial growth and repelling insect reproduction. Mature and systematic technical solutions for processing and utilizing wasabi leaves are also lacking. There is an urgent need to develop a processing method that can effectively utilize the functional components of wasabi leaves and is suitable for industrial production, in order to achieve high-value resource utilization of this agricultural by-product, extend the wasabi industrial chain, and improve the economic benefits of planting. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a wasabi insect repellent, its preparation method and application. The insect repellent of the present invention has the effects of anti-mildew, repellency and antifeedant, and is suitable for the field of grain storage, solving the problems of waste of existing wasabi leaf resources and the single effect and short duration of plant-derived insect repellents.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a wasabi insect repellent, comprising the following steps: (1) Wash, dry and break the cell walls of fresh wasabi to obtain wasabi paste; (2) Mix wasabi mud with water, extract it under a high-voltage pulse electric field, treat it with ultrasound, and then filter it to obtain the extract and wasabi residue; (3) The extract was adsorbed and encapsulated by a composite adsorption and encapsulation carrier to obtain wasabi encapsulated material; (4) Mix the wasabi residue with the compound enzyme, perform enzymatic hydrolysis, dry, and pulverize to obtain the hydrolysate; (5) Mix the wasabi encapsulated material and the enzymatic hydrolysate to obtain wasabi insect repellent.

[0006] Preferably, the drying process includes: spreading the wasabi in a single layer until the moisture content of the wasabi evaporates by 30wt%-35wt%.

[0007] Preferably, the material-to-liquid ratio extracted by the high-voltage pulsed electric field is 1:8-10 g / mL, the temperature is 25-30℃, the electric field strength is 20-30 kV / cm, the pulse width is 1-3 μs, the frequency is 80-120 Hz, and the total number of pulses is 6-10.

[0008] Preferably, the ultrasonic treatment is performed at a temperature of 25-30°C, a frequency of 25-35kHz, and a duration of 5-10 minutes.

[0009] Preferably, the composite adsorption and embedding carrier is composed of diatomaceous earth, β-cyclodextrin, and zein in a mass ratio of (4-6):(2-4):(1-3).

[0010] Preferably, the adsorption and encapsulation includes: adding the composite adsorption and encapsulation carrier to the extraction solution and stirring at 25-30℃ and 200-300rpm for 30-40min.

[0011] Preferably, the compound enzyme is composed of cellulase and pectinase; the enzymatic hydrolysis temperature is 45-50℃, the pH value is 5-5.5, and the time is 2.5-3.5h.

[0012] The present invention also provides a wasabi insect repellent obtained according to the above preparation method.

[0013] The present invention also provides an application of the above-mentioned wasabi repellent in the preparation of pest repellent products.

[0014] Preferably, the pest repellent product is a grain storage insect repellent.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a wasabi insect repellent. Wasabi is used as raw material. After washing, drying, and cell wall breaking, it is extracted by high-voltage pulsed electric field and ultrasonic treatment to obtain an extract and wasabi residue. The extract is adsorbed and encapsulated by a composite carrier composed of diatomaceous earth, β-cyclodextrin, and zein to obtain wasabi encapsulated material. The wasabi residue is enzymatically hydrolyzed by a composite enzyme to obtain an enzymatic hydrolysate. The encapsulated material and the enzymatic hydrolysate are mixed to obtain the wasabi insect repellent.

[0016] Performance tests show that the wasabi insect repellent of this invention can prolong the time before the initial appearance of mold and improve the repellency and non-feeding rate of grain storage pests, both of which are superior to the positive control. This invention realizes the resource utilization of wasabi leaves, and the resulting insect repellent has green, efficient, and long-lasting anti-mold and insect-repellent properties, making it suitable for grain storage scenarios. Detailed Implementation

[0017] This invention provides a method for preparing a wasabi insect repellent, comprising the following steps: (1) Wash, dry and break the cell walls of fresh wasabi to obtain wasabi paste; (2) Mix wasabi mud with water, extract it under a high-voltage pulse electric field, treat it with ultrasound, and then filter it to obtain the extract and wasabi residue; (3) The extract was adsorbed and encapsulated by a composite adsorption and encapsulation carrier to obtain wasabi encapsulated material; (4) Mix the wasabi residue with the compound enzyme, perform enzymatic hydrolysis, dry, and pulverize to obtain the hydrolysate; (5) Mix the wasabi encapsulated material and the enzymatic hydrolysate to obtain wasabi insect repellent.

[0018] In this invention, the fresh wasabi preferably includes the roots, stems, and leaves of wasabi, and more preferably wasabi leaves; the drying preferably includes: spreading the wasabi in a single layer until the moisture content of the wasabi evaporates by 30wt%-35wt%, and the moisture evaporation is more preferably 32wt%.

[0019] Step (1) is a pretreatment method for wasabi, in which washing removes mud, impurities and microorganisms from the surface of the raw material; removing free water from the surface of the raw material reduces the difficulty of water control in subsequent processes; drying causes wasabi tissue to lose water, destroys cell turgor pressure, softens tissue structure, and creates conditions for sufficient contact in subsequent high-voltage pulse electric field extraction and enzymatic hydrolysis; cell wall breaking can improve the contact efficiency between water / complex enzyme and substrate in subsequent high-voltage pulse electric field extraction and enzymatic hydrolysis, accelerate the cell wall decomposition rate, and promote the release of insecticidal active ingredients.

[0020] In this invention, the preferred material-to-liquid ratio for extraction by the high-voltage pulsed electric field is 1:15-20 g / mL, more preferably 1:18 g / mL; the preferred temperature is 25-30℃, more preferably 28℃; the preferred electric field strength is 20-30 kV / cm, more preferably 25 kV / cm; the preferred pulse width is 1-3 μs, more preferably 2 μs; the preferred frequency is 80-120 Hz, more preferably 100 Hz; and the preferred total number of pulses is 6-10, more preferably 8.

[0021] This invention utilizes a high-voltage pulsed electric field to break down the cell membrane and cell wall of wasabi cells, forming microporous channels to rapidly release the anthelmintic components within the cells, breaking their confinement and significantly improving extraction efficiency. On the other hand, low-temperature extraction avoids the volatilization and decomposition of pungent volatile anthelmintic components (such as isothiocyanates) in wasabi, increasing the concentration of anthelmintic components in the extract and thus improving the anthelmintic effect.

[0022] The preferred temperature for ultrasonic treatment in this invention is 25-30℃, more preferably 28℃; the preferred frequency is 25-35kHz, more preferably 30kHz; and the preferred time is 5-10min, more preferably 8min.

[0023] This invention utilizes ultrasonic treatment to break down residual cell walls and cell membranes in wasabi mud, accelerating the transfer of active ingredients to the aqueous phase, reducing extraction dead zones, releasing insecticidal active ingredients that were not fully extracted by the high-voltage pulsed electric field, improving extraction efficiency, laying the foundation for subsequent composite adsorption and encapsulation processes, ensuring the purity and content of effective components in the extract, and enhancing the final insecticidal effect.

[0024] The composite adsorption and embedding carrier of the present invention is preferably composed of diatomaceous earth, β-cyclodextrin, and zein in a mass ratio of (4-6):(2-4):(1-3), and the mass ratio is more preferably 5:3:2; the adsorption and embedding preferably includes: adding the composite adsorption and embedding carrier to the extract and stirring at 25-30℃ and 200-300rpm for 30-40min; the amount of the composite adsorption and embedding carrier added is preferably 5%-10% of the mass of the extract, and more preferably 8%; the adsorption and embedding temperature is more preferably 28℃, the stirring speed is more preferably 250rpm, and the time is more preferably 35min.

[0025] The β-cyclodextrin of this invention can encapsulate the volatile and easily degradable insecticidal active ingredients produced by wasabi and microbial fermentation. The zein forms a dense protein film on the surface of the active ingredients. The two work together to prevent the degradation of the active ingredients by the external environment and prolong the duration of the insect repellent's effect. Diatomaceous earth can adsorb the active ingredients in the fermented materials and has a significant removal effect on mold and pests in grain storage.

[0026] In this invention, the composite enzyme is preferably composed of cellulase and pectinase; the cellulase activity is preferably 10,000-30,000 U / g, more preferably 20,000 U / g; the pectinase activity is preferably 5,000-10,000 U / g, more preferably 8,000 U / g; the mass ratio of cellulase to pectinase is preferably 1:(1-3), more preferably 1:2; the amount of the composite enzyme added is preferably 1%-2% of the mass of wasabi residue, more preferably 1.5%; the enzymatic hydrolysis temperature is preferably 45-50℃, more preferably 48℃; the pH value is preferably 5-5.5, more preferably 5.2; and the time is preferably 2.5-3.5 h, more preferably 3 h.

[0027] This invention utilizes cellulase and pectinase to enzymatically hydrolyze wasabi residue, breaking down the unextracted cell walls and releasing residual insect-repelling active ingredients such as allyl isothiocyanate. These active ingredients are distributed on the surface of the hydrolysate, achieving a rapid insect-repelling effect. The resulting small molecule substances can act as carriers to assist in the dispersion and embedding of the insect repellent, improving its stability and dispersibility, extending the sustained-release period of the insect-repelling ingredients, further reducing the volatilization of active ingredients in conjunction with the embedding system, and enhancing the adhesion of the insect repellent in grain storage scenarios, thereby improving its practical application effect.

[0028] This invention presents a synergistic system in insect repellents, where wasabi-encapsulated material and enzymatic hydrolysate form a complementary system that enhances both rapid and sustained-release effects, thereby strengthening insect repellency, mold prevention, and application stability. The active ingredients in the enzymatic hydrolysate are distributed on the material surface, allowing for rapid release and immediate insect repellency. Simultaneously, the small molecules produced by enzymatic hydrolysis act as a dispersion carrier, improving the dispersibility and system stability of the encapsulated material and enhancing the adhesion of the formulation to grain surfaces. The encapsulated material, through its composite encapsulation structure, adsorbs and encapsulates volatile active ingredients, extending the sustained-release period and reducing component loss. Through synergy, the enzymatic hydrolysate provides rapid repellency and enhanced dispersion, while the encapsulated material ensures long-term stability and sustained protection, effectively addressing the issues of volatility, slow onset of action, and short duration of effect in plant-derived insect repellents, significantly improving the practicality of insect repellency and mold prevention in grain storage scenarios.

[0029] The present invention also provides a wasabi insect repellent obtained according to the above preparation method.

[0030] The present invention also provides an application of the above-mentioned wasabi repellent in the preparation of pest repellent products.

[0031] In this invention, the pest repellent product is preferably a grain storage insect repellent.

[0032] The method of using the wasabi insect repellent described in this invention as a grain storage insect repellent is as follows: Pack the wasabi insect repellent into a breathable non-woven fabric bag / porous food-grade plastic mesh box (pore size 0.5-1mm, which ensures the volatilization and release of active ingredients while preventing powder from mixing into rice and flour), with each bag / box containing 3-6g; place the insect repellent bags / boxes according to the storage amount of rice and flour at a ratio of 3-6g / kg, for example, 1 bag for 5kg of rice and flour, and 2-3 bags for 10kg of rice and flour, and evenly distribute / hang them around the storage container.

[0033] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] Unless otherwise specified, the following embodiments are all conventional methods.

[0035] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0036] Diatomaceous earth was sourced from Hebei Hezhen Industrial Co., Ltd., with a mesh size of 325; β-cyclodextrin was sourced from Shandong Jiake Biotechnology Co., Ltd.; and zein was sourced from Shanxi Huada Biotechnology Co., Ltd.

[0037] Example 1 (1) Raw material pretreatment Pick fresh, disease-free wasabi leaves, wash them, remove surface moisture, spread the wasabi leaves in a single layer, and dry them until 32 wt% of the wasabi leaves have evaporated. Then break the cell walls to obtain wasabi paste.

[0038] (2) Extraction of high voltage pulse electric field Wasabi pulp and water were mixed at a material-to-liquid ratio of 1:18 g / mL. High-voltage pulsed electric field extraction was performed at a temperature of 28℃, an electric field strength of 25 kV / cm, a pulse width of 2 μs, a frequency of 100 Hz, and a total of 8 pulses. After ultrasonic treatment at a temperature of 28℃ and a frequency of 30 kHz for 8 minutes, the mixture was filtered to obtain the extract and wasabi residue.

[0039] (3) Adsorption and embedding The extract was mixed with 8% (by weight) of a composite adsorption and embedding carrier, and the mixture was adsorbed and embedded at 28°C and 250 rpm for 35 min. After pressure filtration, the precipitate was freeze-dried under vacuum until the moisture content was 1.35 wt%, pulverized, and passed through an 80-mesh sieve to obtain the wasabi-encapsulated material. The composite adsorption and embedding carrier is composed of diatomaceous earth, β-cyclodextrin, and zein in a mass ratio of 5:3:2.

[0040] (4) Enzymatic hydrolysis Add 1.5% of the wasabi residue mass of compound enzyme to the wasabi residue, enzymatically hydrolyze at 48℃ and pH 5.2 for 3 hours, inactivate the enzyme, freeze dry under vacuum until the moisture content is 1.62wt%, pulverize, and pass through an 80-mesh sieve to obtain the enzymatic hydrolysate. The complex enzyme is composed of cellulase (enzyme activity 20000U / g) and pectinase (enzyme activity 8000U / g) in a mass ratio of 1:2.

[0041] (5) Mixing The wasabi encapsulated material and the enzymatic hydrolysate were mixed and stirred at 100 rpm for 20 min to obtain the wasabi insect repellent.

[0042] Example 2 (1) Raw material pretreatment Pick fresh, disease-free wasabi leaves, wash them, remove surface moisture, spread the wasabi leaves in a single layer, and dry them until 30 wt% of the moisture in the wasabi leaves evaporates. Then break the cell walls to obtain wasabi paste.

[0043] (2) Extraction of high voltage pulse electric field Wasabi pulp and water were mixed at a material-to-liquid ratio of 1:15 g / mL. High-voltage pulsed electric field extraction was performed at a temperature of 25℃, an electric field strength of 25kV / cm, a pulse width of 1μs, a frequency of 80Hz, and a total number of 10 pulses. After ultrasonic treatment at a temperature of 25℃ and a frequency of 25kHz for 10 minutes, the mixture was filtered to obtain the extract and wasabi residue.

[0044] (3) Adsorption and embedding The extract was mixed with 5% (by weight) of a composite adsorption and embedding carrier, and the mixture was adsorbed and embedded at 25°C and 200 rpm for 40 min. After filtration, the precipitate was freeze-dried under vacuum until the moisture content was 2.04 wt%, pulverized, and passed through a 60-mesh sieve to obtain the wasabi-encapsulated material. The composite adsorption and embedding carrier is composed of diatomaceous earth, β-cyclodextrin, and zein in a mass ratio of 4:2:1.

[0045] (4) Enzymatic hydrolysis Add 2% by weight of compound enzyme to the wasabi residue, enzymatically hydrolyze at 45℃ and pH 5 for 3.5 h, inactivate the enzyme, freeze dry under vacuum until the moisture content is 1.37 wt%, pulverize, and pass through a 60-mesh sieve to obtain the enzymatic hydrolysate. The complex enzyme is composed of cellulase (enzyme activity 10000U / g) and pectinase (enzyme activity 5000U / g) in a mass ratio of 1:1.

[0046] (5) Mixing The wasabi-embedded material and the enzymatic hydrolysate were mixed and stirred at 80 rpm for 25 min to obtain the wasabi insect repellent.

[0047] Example 3 (1) Raw material pretreatment Pick fresh, disease-free wasabi leaves, wash them, remove surface moisture, spread the wasabi leaves in a single layer, and dry them until 35 wt% of the moisture in the wasabi leaves evaporates. Then break the cell walls to obtain wasabi paste.

[0048] (2) Extraction of high voltage pulse electric field Wasabi pulp and water were mixed at a material-to-liquid ratio of 1:20 g / mL. High-voltage pulsed electric field extraction was performed at a temperature of 30℃, an electric field strength of 30 kV / cm, a pulse width of 3 μs, a frequency of 120 Hz, and a total of 6 pulses. After ultrasonic treatment at a temperature of 30℃ and a frequency of 35 kHz for 5 min, the mixture was filtered to obtain the extract and wasabi residue.

[0049] (3) Adsorption and embedding The extract was mixed with 10% of the extract mass of a composite adsorption and embedding carrier, and the mixture was adsorbed and embedded at 30℃ and 300 rpm for 30 min. After filtration, the precipitate was freeze-dried under vacuum until the moisture content was 1.88 wt%, pulverized, and passed through a 100-mesh sieve to obtain the wasabi-encapsulated material.

[0050] (4) Enzymatic hydrolysis Add 1.5% of the wasabi residue mass of compound enzyme to the wasabi residue, enzymatically hydrolyze at 50℃ and pH 5.5 for 2.5 hours, inactivate the enzyme, freeze dry under vacuum until the moisture content is 1.49 wt%, pulverize, and pass through a 100-mesh sieve to obtain the enzymatic hydrolysate. The complex enzyme is composed of cellulase (enzyme activity 30000U / g) and pectinase (enzyme activity 10000U / g) in a mass ratio of 1:3.

[0051] (5) Mixing The wasabi-embedded material and the enzymatic hydrolysate were mixed and stirred at 150 rpm for 15 min to obtain the wasabi insect repellent.

[0052] Comparative Example 1 The specific implementation method is the same as in Example 1, except that the compound enzyme is composed of hemicellulase (enzyme activity 30000U / g) and xylanase (enzyme activity 10000U / g) in a mass ratio of 1:3, while other conditions remain unchanged.

[0053] Comparative Example 2 The specific implementation method is the same as in Example 1, except that the wasabi mud in step (1) is directly enzymatically hydrolyzed, and steps (2), (3) and (5) are not performed: 1.5% of the mass of wasabi residue of compound enzyme is added to the wasabi mud, and enzymatic hydrolysis is carried out at a temperature of 48℃ and a pH of 5.2 for 16 hours. The mixture is stirred once every 4 hours to inactivate the enzyme. The mixture is then freeze-dried under vacuum until the moisture content is 1.56wt%, pulverized, and passed through an 80-mesh sieve to obtain wasabi insect repellent. The compound enzyme is composed of cellulase (enzyme activity 20000U / g) and pectinase (enzyme activity 8000U / g) in a mass ratio of 1:2.

[0054] Comparative Example 3 The specific implementation method is the same as that in Example 1, except that steps (4) and (5) are not performed, and the wasabi embedding material obtained in step (3) is wasabi insect repellent.

[0055] Comparative Example 4 The specific implementation method is the same as in Example 1, except that the composite adsorption and encapsulation carrier is composed of zeolite powder, maltodextrin and soy protein isolate in a mass ratio of 5:3:2.

[0056] Comparative Example 5 The specific implementation method is the same as that in Example 1, except that the pulverization in steps (3) and (4) is passed through a 40-mesh sieve.

[0057] Comparative Example 6 The specific implementation method is the same as that in Example 1, except that the pulverization in steps (3) and (4) is passed through a 200-mesh sieve.

[0058] Experimental Example 1 Anti-mold test Test samples: Wasabi insect repellents prepared in Examples 1-3 and Comparative Examples 1-6.

[0059] Positive control: Liangmancang compound spice packet, 20 packets / bag, manufactured by Luoyang Aojian Bioengineering Co., Ltd.

[0060] The tested molds were Aspergillus niger CMCC(F)98029 and Aspergillus flavus CICC 40191. After activation culture, bacterial suspensions were prepared, and the concentration of the bacterial suspensions was 1×10⁻⁶. 6 CFU / mL, mix equal volumes of Aspergillus niger suspension and Aspergillus flavus suspension to obtain mold suspension.

[0061] Experimental Methods: 0.25g of each of the wasabi insect repellent samples from Examples 1-3 and Comparative Examples 1-6, and 0.25g of the positive control powder were weighed and thoroughly mixed with 50g of sterilized indica rice (free from mold and insect infestation). The mixtures were then placed in sterile 250mL Erlenmeyer flasks and designated as the sample group (Examples 1-3, Comparative Examples 1-6) and the positive control group, respectively. An additional 50g of sterilized rice without any added insect repellent served as the blank control group. All experimental groups had three replicates.

[0062] Add 1 mL of mold suspension to each Erlenmeyer flask and mix thoroughly with the rice; adjust the moisture content of the rice to 15 wt%, seal the flasks and allow them to breathe (simulating the grain storage environment).

[0063] All samples were placed in a constant temperature and humidity incubator (temperature 28℃, relative humidity 85%) for continuous incubation. The following indicators were observed and recorded at regular intervals each day (8:00 AM and 6:00 PM): Time of first appearance of mold (d): The appearance of mold colonies with a diameter of ≥0.5mm or the appearance of mold hyphae with a length of ≥1mm is recorded as the first appearance of mold. Record the number of days since the first appearance. If mold is found at 8:00 AM, it is recorded as an integer day. If mold is found at 6:00 PM, it is recorded as half a day. The mold growth levels of each group were statistically analyzed on days 7 and 14, and the classification criteria are shown in Table 1.

[0064] Table 1 Mold Growth Grade Standards

[0065] The initial appearance time of mold and the mold growth grade at 7 days and 14 days were the average values ​​of three parallel samples, rounded to one decimal place. The specific results are shown in Table 2.

[0066] Table 2. Initial appearance time of mold in each group and mold growth grades at 7 days and 14 days.

[0067] Table 2 shows that the initial mold appearance time in the blank control group was only 2.5 days, while the mold growth grades reached 3.3 and 4.0 at 7 and 14 days, respectively. This indicates that without insect repellent, mold can easily and rapidly grow and spread in grains stored in a high-humidity and high-temperature environment. In Examples 1-3, the initial mold appearance time all exceeded 7.8 days, indicating that the insect repellent obtained from the optimized preparation process of this invention can significantly delay the initial mold appearance, effectively inhibit mold growth and reproduction, and its anti-mold performance is superior to the positive control.

[0068] Comparative Example 1, by replacing the types of compound enzymes, reduced the time to initial mold appearance to 5.5 days, indicating that the combination of cellulase and pectinase is more effective than other enzyme combinations in releasing the anti-mold active ingredients of wasabi. Comparative Example 2 only directly enzymatically hydrolyzed wasabi mud, without the use of high-voltage pulsed electric field and ultrasonic treatment to fully release the active ingredients. The amount of anti-mold components released was low, and without the protection of a composite carrier, volatile active ingredients were rapidly lost, failing to form a sustained antibacterial environment, resulting in weak anti-mold ability. Comparative Example 3 only retained the wasabi encapsulated material, discarding the wasabi residue from which the enzymes could be released through enzymatic hydrolysis. The retention of active ingredients resulted in insufficient raw material utilization. Although the encapsulated material provided slow release, it lacked the rapid antibacterial and dispersing synergistic effects of the enzymatic hydrolysate, failing to inhibit late-stage mold outbreaks. Comparative examples 2-3 showed that the combination of enzymatic hydrolysate and wasabi encapsulated material synergistically achieved the effects of releasing anti-mold components, providing stable protection, and sustained antibacterial activity. Comparative example 4, by replacing the composite adsorption and encapsulation carrier, and comparative examples 5-6, by changing the particle size, both resulted in a shorter initial mold appearance time and an increased growth level, indicating that the type of composite adsorption and encapsulation carrier and the particle size are related to mold prevention. The above data show that the process combination in the examples achieved optimal anti-mold performance, and the synergistic effect of each process step effectively improved the insecticide's ability to inhibit mold in grain storage.

[0069] Experimental Example 2 Deworming test Test samples: Wasabi insect repellents prepared in Examples 1-3 and Comparative Examples 1-6.

[0070] Positive control: Liangmancang compound spice packet, 20 packets / bag, manufactured by Luoyang Aojian Bioengineering Co., Ltd.

[0071] The tested pest was the rice weevil in its larval stage.

[0072] Repulsion and food rejection test: A two-way selection method was used, with a partition placed in the center of the insect culture box, dividing the box into two equal-volume areas. In the left area, 50g of indica rice + 0.25g of the test sample (example / comparative example) were placed, with the test sample positioned 10cm above the rice. In the right area, 50g of blank indica rice (without insect repellent) was placed as the control area. In the positive control group, 50g of indica rice + 0.25g of the positive control were placed in the left area, with the positive control positioned 10cm above the rice, and blank indica rice on the right. Three replicates were set up for each group.

[0073] After removing the partition, 50 rice weevils were placed in the center of the culture box. The culture box was sealed and placed in a constant temperature and humidity incubator (temperature 28±1℃, relative humidity 75±5%, photoperiod 12L:12D). The number of pests in the left and right areas was counted at 24h, 7d, and 14d, and the repellency rate was calculated. After 14 days of culture, the remaining indica rice in each group was weighed, and the amount of food consumed and the refusal rate of the pests were calculated.

[0074] Repellency rate (%) = (Number of insects in the blank area - Number of insects in the treated area) / Total number of insects × 100%.

[0075] Refusal to eat rate (%) = (Food intake of control group - Food intake of treatment group) / Food intake of control group × 100%.

[0076] The results of insect count, rice weevil repellency rate, and feeding refusal rate in each treatment area are the average of three parallel samples, rounded to one decimal place. The feeding refusal rate is the average of three parallel samples, rounded to two decimal places. The specific results are shown in Table 3.

[0077] Table 3. Insect count, rice weevil repellency rate, and feeding refusal rate in each treatment area.

[0078] Table 3 shows that the wasabi repellent prepared in this invention exhibits extremely strong repellent activity against rice weevils. The repulsion and feeding rejection data of Examples 1-3 are superior to those of the positive control and all comparative examples, indicating that the wasabi repellent prepared in this invention has an extremely strong and long-lasting repellent effect against rice weevils, while effectively inhibiting the feeding behavior of rice weevils, demonstrating significant advantages in its core insecticidal performance.

[0079] Comparative Example 1, by replacing the compound enzyme, demonstrates that the combined hydrolysis of cellulase and pectinase can fully release the insecticidal active ingredients of wasabi, which is the basis for improving the repellent effect. Comparative Example 2, while the enzymatic hydrolysate can rapidly release the active ingredients and take effect, lacks an encapsulation structure to lock in volatile substances, resulting in a short duration of effect and failing to meet the needs of long-term grain storage; it can only provide short-term insect repellency. Comparative Example 3, while the encapsulated material can provide long-lasting and slow-release, has a slow initial repellent effect; furthermore, it lacks the dispersion enhancement and adhesion enhancement of small enzymatically hydrolyzed molecules, resulting in uneven dispersion of the encapsulated material on the grain surface and slow release of the active ingredients. The low release efficiency and overall weak insect repellent and antifeedant effects of Comparative Examples 2 and 3, respectively, resulted in a decrease in both rapid and sustained efficacy, demonstrating the synergistic effect of the combination of enzymatic hydrolysate and encapsulation in this invention. Comparative Example 4, by replacing the composite adsorption and encapsulation carrier, significantly reduced both repellency and antifeedant rates, indicating that the composite adsorption and encapsulation carrier of this invention can more effectively protect the insecticidal active ingredient and prolong its duration of effect. Comparative Examples 5 and 6, by changing the particle size, demonstrated that a suitable particle size can ensure the volatilization and release efficiency of the active ingredient. Overall, the process system of these examples achieves a dual improvement in repellency and antifeedant effects. Precise control of each step allows the insect repellent to exhibit excellent application performance in the control of stored grain pests, showing promising application prospects.

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a wasabi insect repellent, characterized in that, Includes the following steps: (1) Wash, dry and break the cell walls of fresh wasabi to obtain wasabi paste; (2) Mix wasabi mud with water, extract it under a high-voltage pulse electric field, treat it with ultrasound, and then filter it to obtain the extract and wasabi residue; (3) The extract was adsorbed and encapsulated by a composite adsorption and encapsulation carrier to obtain wasabi encapsulated material; (4) Mix the wasabi residue with the compound enzyme, perform enzymatic hydrolysis, dry, and pulverize to obtain the hydrolysate; (5) Mix the wasabi encapsulated material and the enzymatic hydrolysate to obtain wasabi insect repellent.

2. The preparation method according to claim 1, characterized in that, The drying process includes spreading the wasabi in a single layer until the moisture content of the wasabi evaporates by 30wt%-35wt%.

3. The preparation method according to claim 1, characterized in that, The high-voltage pulsed electric field extraction has a material-to-liquid ratio of 1:8-10 g / mL, a temperature of 25-30℃, an electric field strength of 20-30 kV / cm, a pulse width of 1-3 μs, a frequency of 80-120 Hz, and a total number of 6-10 pulses.

4. The preparation method according to claim 1, characterized in that, The ultrasonic treatment is performed at a temperature of 25-30℃, a frequency of 25-35kHz, and a duration of 5-10 minutes.

5. The preparation method according to claim 1, characterized in that, The composite adsorption and embedding carrier is composed of diatomaceous earth, β-cyclodextrin, and zein in a mass ratio of (4-6):(2-4):(1-3).

6. The preparation method according to claim 1, characterized in that, The adsorption and embedding process includes: adding the composite adsorption and embedding carrier to the extraction solution and stirring at 25-30℃ and 200-300rpm for 30-40min.

7. The preparation method according to claim 1, characterized in that, The complex enzyme is composed of cellulase and pectinase; the enzymatic hydrolysis temperature is 45-50℃, the pH value is 5-5.5, and the time is 2.5-3.5h.

8. A wasabi insect repellent obtained by the preparation method according to any one of claims 1-7.

9. The use of the wasabi repellent according to claim 8 in the preparation of pest repellent products.

10. The application according to claim 9, characterized in that, The pest repellent product is a grain storage insect repellent.

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