Chinese herbal medicine extract-based disease control method for Chinese yam in storage period

Abstract

The invention discloses a Chinese herbal medicine extract-based Chinese yam storage period disease control method, and relates to the technical field of agricultural product storage and fresh-keeping, and Chinese herbal medicine extract is uniformly sprayed on the surface of Chinese yam to realize storage period fresh-keeping and disease control. The composite Chinese herbal medicine extract comprises the following components: a fresh-keeping component and an antifungal spectrum component. The fresh-keeping component comprises the following components: pomegranate rind, golden cypress, honeysuckle, fructus cnidii and houttuynia cordata; the antifungal spectrum components comprise the following components: clove and folium artemisiae argyi. The fresh-keeping components in the compound Chinese herbal medicine extract contain tannin, alkaloid and the like, the antifungal spectrum components contain eugenol, volatile oil and the like, and main pathogenic bacteria such as penicillium, fusarium, rhizopus and the like in the storage period of the Chinese yam can be efficiently inhibited through the synergistic effect. A film formed by the slow-release film-forming agent can slowly release antibacterial components, the prevention and treatment time efficiency is prolonged to 90 days, different storage period requirements can be met in cooperation with gradient use of dilution, and the decay risk in the middle and later periods is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of agricultural product storage and preservation, and in particular to a Dioscorea opposita Thunb. storage period disease prevention method based on Chinese herbal medicine extract. BACKGROUND

[0002] Dioscorea opposita Thunb. is an important crop of food and medicine, which is widely planted in China. Dioscorea opposita Thunb. is rich in nutrients and has high edible value and medicinal efficacy, and is deeply loved by consumers. However, Dioscorea opposita Thunb. is easily attacked by various diseases during storage, resulting in quality decline, rotting and metamorphic change, and causing huge economic losses.

[0003] At present, the prevention and control methods of Dioscorea opposita Thunb. storage period diseases mainly include physical prevention and control, chemical prevention and control and biological prevention and control. The physical prevention and control method such as controlling the temperature, humidity and ventilation conditions of the storage environment can inhibit the occurrence of diseases to a certain extent, but it is difficult to completely eliminate the invasion of pathogenic bacteria. Chemical prevention and control is the most widely used method at present, which mainly uses chemical fungicides to treat Dioscorea opposita Thunb. to achieve the purpose of preventing and controlling diseases. Commonly used chemical fungicides include carbendazim, prochloraz and the like. These fungicides can effectively inhibit the growth and reproduction of pathogenic bacteria and significantly reduce the disease incidence. Chemical prevention and control has many drawbacks. Long-term and large-scale use of chemical fungicides can lead to drug resistance of pathogenic bacteria, making the prevention and control effect gradually decrease. Chemical pesticide residues can pose potential threats to the environment and human health, which does not meet the development requirements of green agriculture and food safety. Frequent use of chemical pesticides can also destroy the ecological balance and affect the sustainable development of agriculture. Biological prevention and control is to use beneficial microorganisms or their metabolites to inhibit the growth and reproduction of pathogenic bacteria, such as using antagonistic bacteria and biological fungicides. Biological prevention and control has the advantages of environmental protection and safety, but it has problems such as unstable prevention and control effect, slow action speed and high cost, which is difficult to meet the needs of large-scale commercial storage.

[0004] In the existing chemical prevention and control technology, although a large amount of chemical fungicides can inhibit Dioscorea opposita Thunb. storage period diseases in the short term, chemical pesticides residues in Dioscorea opposita Thunb. and the environment can harm human health and the ecological environment, and can also lead to drug resistance of pathogenic bacteria, resulting in a decrease in the prevention and control effect year by year. Therefore, there is an urgent need for new safe and sustainable prevention and control means. For example, the commonly used fungicides such as carbendazim and prochloraz have poor effects after long-term use.

[0005] Simply relying on physical prevention and control methods such as adjusting the temperature, humidity and ventilation of the storage environment cannot completely eliminate or inhibit the growth of pathogenic bacteria, and cannot fundamentally solve the problem of Dioscorea opposita Thunb. being attacked by diseases during storage. Dioscorea opposita Thunb. is still prone to rotting and metamorphic change in varying degrees in such an environment, resulting in great losses.

[0006] Biological control, which uses beneficial microorganisms or their metabolites, is environmentally friendly but relatively expensive, limiting its large-scale application. Furthermore, its effectiveness is significantly affected by environmental factors and its stability is poor, making it difficult to guarantee optimal control under varying storage conditions. For example, antagonistic bacteria lose activity in certain environments, making them ineffective in inhibiting pathogens.

[0007] Traditional storage methods cannot prevent the loss of nutrients and quality deterioration in yams, such as a poor taste and nutrient breakdown, making it difficult to meet market demand for high-quality yams. Furthermore, traditional storage methods can easily cause yams to sprout, depleting their nutrients and reducing their value.

[0008] Therefore, developing a safe, effective, and environmentally friendly method for controlling yam storage diseases is of great practical significance. Chinese herbal extracts, which come from a wide range of sources and contain complex and diverse ingredients, possess a variety of biological activities, including antibacterial, antioxidant, and immunomodulatory effects. Applying Chinese herbal extracts to control yam storage diseases is expected to provide a new approach to address the shortcomings of existing control methods. Summary of the Invention

[0009] In order to solve the technical problem of preventing and controlling diseases during the storage period of yam, the present invention provides a method for preventing and controlling diseases during the storage period of yam based on Chinese herbal medicine extracts. The following technical solution is adopted: A method for preventing and controlling diseases of yam during storage based on Chinese herbal medicine extracts, wherein the Chinese herbal medicine extracts are evenly sprayed on the surface of the yam to achieve freshness preservation and disease prevention during storage, comprising the following steps: Step 1, preparing a composite Chinese herbal extract, wherein the composite Chinese herbal extract comprises a fresh-keeping component and an antifungal spectrum component; Step 2, concentrating the compound Chinese herbal medicine extract under reduced pressure; Step 3, emulsifying and stabilizing the composite Chinese herbal medicine extract after reduced pressure concentration; Step 4, compounding the sustained-release film-forming agent with the emulsified and stabilized composite Chinese herbal medicine to obtain a compound liquid; Step 5: Remove the damaged, diseased tissue and dust on the surface of the yam; Step 6: Spray the diluted compound liquid on the surface of the yam.

[0010] Optionally, the compound Chinese herbal extract comprises the following components: 90wt%-95wt% of a freshness-preserving component and 5wt%-10wt% of an antifungal spectrum component.

[0011] Optionally, the fresh-keeping component includes the following components: 16wt%-20wt% of pomegranate peel, 16wt%-20wt% of phellodendron, 16wt%-20wt% of honeysuckle, 16wt%-20wt% of cnidium monnieri, and 16wt%-20wt% of houttuynia cordata; The anti-fungal spectrum component includes the following components: clove 4wt%-6wt%, mugwort 2wt%-4wt%.

[0012] Optionally, the slow-release film-forming agent includes the following components: chitosan 0.2wt%-0.4wt%, citric acid 0.05wt%-0.15wt%, glycerol 0.5wt%-1.5wt%, 1% acetic acid solution 18wt%-25wt%, and deionized water 75wt%-80wt%.

[0013] Optionally, in step 1, the preparation of the composite Chinese herbal medicine extract includes the following steps: Step 11, pomegranate husk, Chinese cork, honeysuckle, cnidium, fishy grass, clove, and mugwort are mixed in a weight ratio, and a pulverizer is used to grind the mixture into coarse powder and pass through a 20-30 mesh sieve to obtain the powder; Step 12, the powder is added to 4-5 times the amount of 99% alcohol, stirred uniformly, and sealed; Step 13, 45-50 degree water bath immersion for 6-10 hours, stirring 1-2 times per hour during the period; Step 14, filter with gauze or filter paper, collect the filtrate to obtain the composite Chinese herbal medicine extract.

[0014] Optionally, the residue after filtration in step 14 is soaked again with 2-3 times the amount of 99% alcohol for 1 time, and all the filtrates are combined to obtain the composite Chinese herbal medicine extract.

[0015] Optionally, in step 3, a rotary evaporator is used for vacuum concentration, a condenser tube is connected to a water circulation cooling system with a temperature of 5-10℃, the composite Chinese herbal medicine extract is poured into a rotary evaporator flask, the water bath temperature is set to 40-45℃, and the rotation speed is set to 50-60r / min, and the extract is concentrated under vacuum; Continue to observe the volume of the concentrated liquid, stop heating when the volume is reduced to 15-25% of the original filtrate volume, close the vacuum valve, and take out the concentrated liquid after pressure balance; Filter the concentrated liquid with a 0.4μm-0.5μm microporous filter membrane to obtain the concentrated extract.

[0016] Optionally, a food-grade emulsifier compounding system is used, 1.0%-1.5% of the emulsifier is added based on the mass of the concentrated extract, the concentrated extract is poured into an emulsifying tank, the stirring speed is set to 800-1200r / min, the emulsifier is slowly added, and the mixture is stirred for 3-6 minutes for preliminary dispersion; Increase the stirring speed to 2500-3500r / min, and at the same time, increase the water bath temperature to 50℃-55℃, continue to shear and emulsify for 20-30 minutes to form a uniform emulsion; Turn off the heating, keep the stirring speed at 800-1200r / min, and stop stirring after cooling to room temperature.

[0017] Optionally, in step 4, the chitosan is weighed according to the proportion by weight, slowly added into 1% acetic acid solution, stirred by a magnetic stirrer at a speed of 500-700 r / min for 25-35 minutes until completely dissolved to form a transparent chitosan solution; Citric acid and glycerol are sequentially added into the chitosan solution, and continue to stir for 10-20 minutes, wherein the citric acid is used to adjust the pH to 5.0-5.5; Deionized water is added to constant volume, and after uniform stirring, it is left to stand for 25-35 minutes; The emulsified and stabilized compound Chinese herbal medicine extract is mixed with the sustained-release film-forming agent at a volume ratio of 1:1, poured into a stirring tank, and stirred at a speed of 600-1000 r / min to form a uniform compound liquid.

[0018] Optionally, in step 6, the dilution multiple is adjusted according to the variety and storage period of yam: For short-term storage of less than or equal to 3 months, a dilution multiple of 900-1100 is used; For long-term storage of more than 3 months, a dilution multiple of 400-600 is used; The required compound liquid volume and deionized water volume are calculated according to the dilution multiple, one-third of the compound liquid volume and deionized water are added first, stirred at a speed of about 250-350 r / min for 1-2 minutes, then the remaining two-thirds of the compound liquid volume and deionized water are slowly added, and continue to stir for 2-3 minutes until the solution is uniform to obtain a dilution liquid; a high-pressure atomizing sprayer is used, the nozzle is rinsed with the dilution liquid in advance, the yam is laid flat on a breathable grid frame, the front surface is sprayed for 20-40 seconds, and after standing for 1-3 minutes, the back surface is sprayed for 20-40 seconds, and the yam is naturally air-dried for 3-4 hours after spraying.

[0019] In summary, the present application includes at least one of the following beneficial technical effects: The present application can provide a yam storage period disease prevention method based on Chinese herbal medicine extract. In the compound Chinese herbal medicine extract, the preservative components contain tannins and alkaloids, and the antifungal spectrum components contain eugenol and volatile oil, which can synergistically inhibit the main pathogenic bacteria of yam during storage, such as penicillium, fusarium, rhizopus, etc. The film formed by the sustained-release film-forming agent can slowly release the antibacterial components, prolong the prevention time to 60-90 days, and can meet the needs of different storage periods by using the gradient of dilution, which can significantly reduce the risk of decay in the middle and late stages.

[0020] The extract is derived from Chinese herbal medicine, and the components can be naturally degraded, avoiding the residue problem of chemical fungicides, improving the safety of yam for eating, and meeting the food safety standards.

[0021] No toxic or harmful substances are discharged during the production and use process, and there is no pollution to the soil, water sources and cold storage environment. In addition, film-forming agents such as chitosan are biodegradable, reducing packaging waste pollution.

[0022] The antioxidant components in the extract can inhibit the browning of yam, and cooperate with film-forming agents to reduce water loss. After storage, the yam has a bright color and a firm texture, which is significantly higher than the blank control.

[0023] Avoiding problems such as starch conversion and vitamin loss in traditional storage, the retention rate of yam's polysaccharides, amino acids and other nutrients is greatly improved, and the taste does not deteriorate significantly.

[0024] Steps such as reduced pressure concentration and emulsification stabilization improve the utilization rate of effective ingredients, reduce raw material consumption, and lower production costs.

[0025] The spraying process is suitable for large-scale production and can also be used for manual operation by small farmers; the gradient design of the dilution multiple is suitable for different varieties and storage conditions and has a wide range of applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flow chart of a method for preventing and controlling diseases of yam during storage based on Chinese herbal medicine extracts. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below with reference to the accompanying drawings.

[0028] The embodiment of the present invention discloses a method for preventing and controlling diseases of yam during storage based on Chinese herbal medicine extracts.

[0029] Reference Figure 1 Example 1: A method for preventing and controlling diseases of yam during storage based on Chinese herbal medicine extracts, wherein the Chinese herbal medicine extracts are evenly sprayed on the surface of the yam to achieve storage and disease prevention, comprising the following steps: Step 1, preparing a composite Chinese herbal extract, wherein the composite Chinese herbal extract comprises a fresh-keeping component and an antifungal spectrum component; Step 2, concentrating the compound Chinese herbal medicine extract under reduced pressure; Step 3, emulsifying and stabilizing the composite Chinese herbal medicine extract after reduced pressure concentration; Step 4, compounding the sustained-release film-forming agent with the emulsified and stabilized composite Chinese herbal medicine to obtain a compound liquid; Step 5: Remove the damaged, diseased tissue and dust on the surface of the yam; Step 6: Spray the diluted compound liquid on the surface of the yam.

[0030] By adopting the above technical scheme, in the composite Chinese herbal medicine extract, the preservative components (pomegranate peel, Chinese cork tree, etc.) contain tannins, alkaloids and other components, the antifungal spectrum components (clove, mugwort leaf) contain eugenol, volatile oil, etc., and the synergistic effect can efficiently inhibit the main pathogenic bacteria of yam during storage, such as penicillium, fusarium, rhizopus, etc.

[0031] The film formed by the slow-release film-forming agent can slowly release the antibacterial components, prolong the prevention and control time to 60-90 days, and can meet the needs of different storage periods when used with 500-1000 times diluted gradient, significantly reducing the risk of rotting in the middle and late stages.

[0032] The extract is derived from Chinese herbal medicine, and the components can be naturally degraded, avoiding the residue problem of chemical fungicides (such as carbendazim), improving the safety of yam for eating, and meeting the food safety standards.

[0033] There is no emission of toxic and harmful substances during production and use, and there is no pollution to soil, water source and cold storage environment, and the film-forming agent such as chitosan is biodegradable, reducing the pollution of packaging waste.

[0034] The antioxidant components (such as honeysuckle chlorogenic acid) in the extract can inhibit the browning of yam, and the film-forming agent can reduce water loss, and the stored yam has bright color and firm texture, which is significantly higher than the blank control.

[0035] Avoiding the problems of starch conversion and vitamin loss in traditional storage, the retention rate of polysaccharide, amino acid and other nutrients in yam is greatly improved, and the taste is not obviously deteriorated.

[0036] The steps of reduced pressure concentration, emulsification stabilization and the like improve the utilization rate of effective components, reduce the consumption of raw materials, and reduce the production cost.

[0037] The spraying process can be adapted to large-scale production (such as assembly line spraying), and can also be used for manual operation by small farmers; the gradient design of dilution multiple is suitable for different varieties (such as small white beak yam, double stick yam) and storage conditions (cold storage, normal temperature storage), and has wide applicability.

[0038] Optionally, the composite Chinese herbal medicine extract comprises the following components: 90wt%-95wt% of preservative components, and 5wt%-10wt% of antifungal spectrum components.

[0039] Preferably, the preservative components are 95wt%, and the antifungal spectrum components are 5wt%.

[0040] Optionally, the preservative components comprise the following components: 16wt%-20wt% of pomegranate peel, 16wt%-20wt% of Chinese cork tree, 16wt%-20wt% of honeysuckle, 16wt%-20wt% of corydalis, and 16wt%-20wt% of fishy grass; The antifungal spectrum components comprise the following components: 4wt%-6wt% of clove and 2wt%-4wt% of mugwort leaf.

[0041] Preferably, the fresh-keeping component includes the following components: pomegranate peel 18.18wt%, Huangbo 18.18wt%, honeysuckle 18.18wt%, Cnidium 18.18wt%, fishy grass 18.18wt%; The antifungal spectrum component includes the following components: clove 5.45wt%, mugwort leaf 3.63wt%.

[0042] By adopting the above technical scheme, pomegranate peel, Huangbo, honeysuckle, Cnidium, and fishy grass are mixed in the proportion of 18.18wt% (the total is 90.9wt%, which is suitable for the range of 90wt%-95wt%). The tannin of pomegranate peel and the berberine of Huangbo enhance the inhibition of bacteria; The chlorogenic acid of honeysuckle and the fishy grassin of fishy grass strengthen the oxidation resistance and reduce the browning of yam; The coumarin component of Cnidium specifically inhibits the spore germination of mold.

[0043] The antifungal spectrum is precisely supplemented: in the 5wt% antifungal spectrum component, the eugenol of clove (4wt%-6wt%) has a strong destructive effect on the fungal cell membrane, and the volatile oil of mugwort leaf (2wt%-4wt%) can kill air-borne pathogenic bacteria in a broad spectrum. The two components are synergistic with the fresh-keeping component, so that the antibacterial spectrum covers more than 90% of the pathogenic bacteria (such as penicillium, fusarium, and soft rot bacteria) during the storage period of yam, and the prevention and control efficiency is greatly improved compared with single component.

[0044] Preferably, 95wt% of the fresh-keeping component and 5wt% of the antifungal spectrum component are used to reduce the irritation of high-concentration antifungal components and avoid burning the skin of yam, while reducing the cost of raw materials; Under this proportion, the sensory score of yam is the same as that of the 10wt% antifungal component scheme, but the cost of raw materials is greatly reduced, which is more suitable for large-scale application.

[0045] Optionally, the slow-release film-forming agent includes the following components: chitosan 0.2wt%-0.4wt%, citric acid 0.05wt%-0.15wt%, glycerol 0.5wt%-1.5wt%, 1% acetic acid solution 18wt%-25wt%, and deionized water 75wt%-80wt%.

[0046] Preferably, the slow-release film-forming agent includes the following components: chitosan 0.3wt%, citric acid 0.10wt%, glycerol 1wt%, 1% acetic acid solution 20wt%, and deionized water 78.6wt%.

[0047] By adopting the above technical scheme, chitosan is used as a film-forming base material, and a film with uniform thickness (about 5-8 μm) and excellent mechanical properties can be formed at a concentration of 0.3 wt%, which avoids the film being too thin to be damaged at 0.2 wt% and the film being too thick to have poor air permeability at 0.4 wt%. The water vapor generated by the respiration of yam can be discharged through the film to avoid local dampness and mold.

[0048] Glycerol is used as a plasticizer, and a proportion of 1 wt% can improve the flexibility of the chitosan film, solve the problem of brittle and hard film of pure chitosan film, and especially suitable for slight friction of yam during transportation and stacking. The film integrity retention rate is more than 90%.

[0049] Citric acid can stabilize the pH of the film-forming agent at 5.0-5.5, which can ensure the sufficient dissolution of chitosan and maintain the stability of active ingredients (such as chlorogenic acid and berberine) in the Chinese herbal medicine extract.

[0050] A 20 wt% 1% acetic acid solution can completely dissolve 0.3 wt% chitosan, while reducing the amount of acetic acid and reducing the potential impact of residual acetic acid on the flavor of yam.

[0051] The dense structure of the chitosan film can slowly release the wrapped Chinese herbal medicine extract, wherein: 50% is released in the first 30 days (quickly inhibits initial pathogenic bacteria), 30-60 days release 30% (control the risk of mold in the middle period), 60-90 days release 20% (delay the late aging and corruption), Compared with the direct spraying scheme without film-forming agent, the prevention and control period is prolonged by 2 times.

[0052] 78.6 wt% of deionized water controls the viscosity of the film-forming agent at 50-60 mPa・s, which is suitable for spraying after dilution and can quickly form a film on the surface of yam.

[0053] All components (chitosan, citric acid, glycerol, etc.) are food-grade raw materials, which meet the GB2760 standard, and can be naturally metabolized with yam after film formation without chemical residue risk; and the material is biodegradable, and the degradation rate of the waste film is 95% in 3 months in the soil without environmental pollution.

[0054] Optionally, in step 1, the preparation of the composite Chinese herbal medicine extract includes the following steps: Step 11, pomegranate peel, Huangbo, honeysuckle, snakegourd, fishy-smelling grass, clove, and eucalyptus are mixed according to the weight ratio, and a coarse powder is obtained by crushing the mixture through a 20-mesh sieve; Step 12, the powder is added to 5 times the amount of 99% alcohol, stirred uniformly, and sealed; Step 13, 45-50 degree water bath immersion for 6-10 hours, stirring 1-2 times per hour during the period. Step 14, filter with gauze or filter paper, collect the filtrate to obtain the composite Chinese herbal medicine extract.

[0055] Optionally, the residue after filtration in step 14 is soaked again with 2-3 times the amount of 99% alcohol, and all the filtrates are combined to obtain the composite Chinese herbal medicine extract.

[0056] Optionally, in step 3, rotary evaporator is used for vacuum concentration, and the condenser is connected to a water circulation cooling system with a temperature of 5-10°C. The composite Chinese herbal medicine extract is poured into a rotary evaporator flask, the water bath temperature is set to 40-45°C, and the rotation speed is set to 50-60 r / min. The concentrated extract is obtained under vacuum conditions. The volume of the concentrated liquid is continuously observed, and heating is stopped when the volume is reduced to 15-25% of the original filtrate volume. The vacuum valve is closed, and the concentrated liquid is removed after the pressure is balanced. The concentrated liquid is filtered with a 0.4-0.5 μm microporous filter membrane to obtain the concentrated extract.

[0057] Optionally, a food-grade emulsifier complex system is used, and 1.0-1.5% of the emulsifier is added based on the mass of the concentrated extract. The concentrated extract is poured into an emulsification tank, the stirring speed is set to 800-1200 r / min, and the emulsifier is slowly added. Stir for 3-6 minutes to achieve initial dispersion. Increase the stirring speed to 2500-3500 r / min, and raise the water bath temperature to 50-55°C. Continue to shear and emulsify for 20-30 minutes to form a uniform emulsion. Turn off the heating, maintain the stirring speed at 800-1200 r / min, and cool to room temperature to stop stirring.

[0058] Optionally, in step 4, chitosan is weighed according to the weight ratio and slowly added to 1% acetic acid solution. Stir with a magnetic stirrer at a speed of 500-700 r / min for 25-35 minutes until completely dissolved to form a transparent chitosan solution. Add citric acid and glycerol to the chitosan solution in sequence, and continue to stir for 10-20 minutes. The citric acid is adjusted to a pH of 5.0-5.5. Add deionized water to the volume, stir evenly, and let stand for 25-35 minutes. Mix the emulsified and stabilized composite Chinese herbal medicine extract with the sustained-release film-forming agent at a volume ratio of 1:1, pour into a stirring tank, and start stirring at a speed of 600-1000 r / min. Stir at room temperature for 15-25 minutes to form a uniform complex solution.

[0059] Optionally, in step 6, the dilution ratio is adjusted according to the variety and storage period of yam: For short-term storage of less than or equal to 3 months, use a dilution ratio of 900-1100 times. Long-term storage for more than 3 months, using a dilution ratio of 400-600 times; According to the dilution ratio, calculate the required complex liquid volume and deionized water volume, add one-third of the volume of the complex liquid and deionized water first, stir at a speed of about 250-350 r / min for 1-2 minutes; then slowly add the remaining two-thirds of the volume of the complex liquid and deionized water, continue to stir for 2-3 minutes, until the solution is uniform to obtain the dilution liquid; use a high-pressure atomizing sprayer, rinse the nozzle with the dilution liquid in advance, lay the yam flat on the breathable grid frame, first spray the front for 20-40 seconds, turn over after 1-3 minutes and spray the back for 20-40 seconds, and then naturally air dry the yam for 3-4 hours after spraying.

[0060] By using the above technical scheme, by using food-grade complex emulsifier (1.0%-1.5% addition amount), emulsifying for 20-30 minutes under the condition of 2500-3500 r / min high-speed shearing and 50-55°C water bath, the fat-soluble ingredients (such as cnidilide, volatile oil of artemisia leaf) and water-soluble ingredients (such as berberine in phellodendri cortex) can form a uniform emulsion, avoiding stratification.

[0061] The stability of the emulsion supports the subsequent process: when the uniformly dispersed extract is compounded with the slow-release film-forming agent, the local concentration that is too high can be avoided, which causes the film surface to be rough, the film-forming uniformity is improved by 40%, and the effective antibacterial dose can be obtained on each part of the yam surface.

[0062] In step 4, the emulsified extract is mixed with the slow-release film-forming agent at a volume ratio of 1:1, which cooperates with the dense structure of the chitosan film to achieve gradient release of the antibacterial ingredients: 50% in the first 30 days (rapid inhibition of initial pathogenic bacteria), 30-60 days (control of intermediate mold), 60-90 days (delay of late corruption), which is 2 times longer than the scheme without the film-forming agent (from 30 days to 90 days).

[0063] Optimization of film-forming agent preparation parameters: magnetic stirrer speed 500-700 r / min, stirring time 25-35 minutes, which can ensure that the chitosan is completely dissolved (without undissolved particles), and the pH is adjusted to 5.0-5.5 with citric acid to stabilize the swelling rate of the film at 15%-20% (to avoid excessive swelling that causes premature release of ingredients), further ensuring the slow-release stability.

[0064] In step 6, the dilution design of 900-1100 times (short-term) / 400-600 times (long-term) can accurately match different yam varieties (such as double-stick yam with thick skin vs. small white mouth yam with thin skin) and storage periods, avoiding high concentration stimulation (such as browning) to yam, while ensuring long-term protection at low concentration, covering more than 90% of cultivated varieties.

[0065] The spraying mode of high-pressure atomizing nozzle combined with 20-40 seconds of front spraying + 20-40 seconds of back spraying makes the surface of yam covered by 100% of the liquid medicine (only 80%-85% by traditional rinsing), and the film thickness is uniform (5-8 pm), without local accumulation or missed spraying, and the rot index can be controlled at 0% (the highest blank control is 68.33%).

[0066] From extraction (alcohol can be completely evaporated), emulsification (food-grade emulsifier) to film formation (chitosan, citric acid and other degradable components), all materials meet the GB2760 food safety standard, and the chemical residue in yam is less than 0.01 mg / kg, which is much lower than the national standard limit (0.1 mg / kg).

[0067] Compared with the traditional water bath, the energy saving of vacuum concentration is 20%, the emulsification and film formation processes can be integrated into the assembly line (1000 kg of yam can be processed per hour), and the design of secondary utilization of raw materials, gradient dilution and other designs makes the unit storage cost controlled at 0.3 yuan / kg (0.5 yuan / kg for chemical fungicides and 0.8 yuan / kg for biological control), which has significant economic advantages.

[0068] Through the optimization of the whole process parameters of “extraction-concentration-emulsification-film formation-application”, the synergy of “efficient utilization of raw materials-high activity retention of components-long-term stable effect-safety and economic adaptation” is realized, which is significantly better than the existing technology, and the storage period of yam can be extended from 3 months to 6-9 months, the rot rate is controlled at a very low level, and the excellent quality is maintained, which is suitable for large-scale agricultural production and application.

[0069] The following specific examples illustrate the implementation principle of a yam storage period disease control method based on Chinese herbal medicine extract: Location: yam storage refrigerator in a rural fruit and vegetable wholesale market; Tested yam varieties: Variety 1: small white beak yam; Variety 2: local purple medicine; Variety 3: Yulin purple medicine; Variety 4: double stick yam; Variety 5: white jade yam; On April 10, 2024, the surface of yam was treated by the following method: Preservation component 95wt%, antifungal spectrum component 5wt%.

[0070] The preservation component includes the following components: pomegranate peel 18.18wt%, Chinese cork tree 18.18wt%, honeysuckle 18.18wt%, cnidium 18.18wt%, fishy smell grass 18.18wt%; The antifungal spectrum component includes the following components: clove 5.45wt%, mugwort leaf 3.63wt%.

[0071] The slow-release film forming agent comprises the following components: chitosan 0.3 wt%, citric acid 0.10 wt%, glycerol 1 wt%, 1% acetic acid solution 20 wt%, deionized water 78.6 wt%.

[0072] Step 11, mix pomegranate peel, Huangbo, honeysuckle, cnidium, fishy grass, clove, and eucalyptus according to the weight ratio, and use a pulverizer to grind into coarse powder and pass through a 20-mesh sieve to obtain the medicinal powder; Step 12, add 5 times the amount of 99% alcohol to the medicinal powder, stir evenly, and seal; Step 13, soak in a water bath at 50 degrees for hours, stirring every hour for 2 times; Step 14, filter with gauze or filter paper to collect the filtrate to obtain the composite Chinese herbal medicine extract.

[0073] Step 14, the medicinal residue after filtration is soaked again with 2 times the amount of 99% alcohol for 1 time, and all the filtrates are combined to obtain the composite Chinese herbal medicine extract.

[0074] In step 3, rotary evaporator is used for vacuum concentration, the condenser tube is connected to water circulating cooling at 10°C, the composite Chinese herbal medicine extract is poured into the rotary evaporator flask, the water bath temperature is set to 45°C, the rotation speed is 60 r / min, and the concentrate is obtained under vacuum condition; Continue to observe the volume of the concentrated liquid, stop heating when the volume is reduced to 1 / 20 of the original filtrate volume, close the vacuum valve, and take out the concentrated liquid after pressure balance; Filter the concentrated liquid with a 0.5 μm microporous filter membrane to obtain the concentrated extract.

[0075] Optionally, a food-grade emulsifier compounding system is used, 1.2% of the concentrated extract is added to the emulsifier, the concentrated extract is poured into the emulsifying tank, the stirring speed is 1000 r / min, the emulsifier is slowly added, and the stirring is continued for 5 minutes to make it preliminarily dispersed; Increase the rotation speed to 3000 r / min, and at the same time, increase the water bath temperature to 55°C, continue to shear and emulsify for 25 minutes to form a uniform emulsion; Turn off the heating, keep the rotation speed at 1000 r / min, and stop stirring after cooling to room temperature.

[0076] In step 4, chitosan is weighed according to the weight ratio, slowly added to 1% acetic acid solution, stirred with a magnetic stirrer at a rotation speed of 600 r / min for 30 minutes until completely dissolved, and a transparent chitosan solution is formed; Add citric acid and glycerol to the chitosan solution in turn, continue to stir for 15 minutes, and adjust the pH of citric acid to 5.2; Add deionized water to constant volume, stir evenly, and stand for 30 minutes; The emulsified and stabilized compound Chinese herbal medicine extract was mixed with the sustained-release film forming agent at a volume ratio of 1:1, poured into a stirring tank, and stirred at a speed of 800 r / min to form a uniform compound liquid.

[0077] In step 6, a dilution ratio of 600 times was used; The required compound liquid volume and deionized water volume were calculated according to the dilution ratio, one-third of the compound liquid volume and deionized water were added first, and stirred at a speed of about 300 r / min for 2 minutes; then the remaining two-thirds of the compound liquid volume and deionized water were slowly added, and stirred for another 3 minutes until the solution was uniform to obtain the dilution liquid; a high-pressure atomizing sprayer was used to rinse the nozzle with the dilution liquid in advance, the yam was laid flat on the breathable grid frame, the front surface was sprayed for 30 seconds first, and then the back surface was sprayed for 30 seconds after being turned over, and the yam was naturally air-dried for 4 hours after spraying.

[0078] After drying, it was stored in a cold storage at 2-5°C. Other cold storage management measures were normally managed.

[0079] The control group did not use the extract of the traditional Chinese medicine.

[0080] The rot rates and sensory qualities of different varieties of yam were investigated on July 10: 1. Rot rate: Rot index statistics method: according to the rot degree of the surface of yam, it was divided into 0-4 levels: 0 level - no rot phenomenon on the surface; 1 level - the rot area on the surface is 0-1 / 10; 2 level - the rot area on the surface is 1 / 10-1 / 4; 3 level - the rot area on the surface is 1 / 4-1 / 2; 4 level - the rot area on the surface is 1 / 2-1; 2. Sensory quality: the sensory quality was counted every 14 days, and the score was counted. The score standard is shown in Table 1: Table 1 Score Scoring criteria 5 points The epidermis is smooth and complete, with bright color and consistent with the characteristics of the variety; no wrinkles, no mildew; hard texture, no indentation when pressed with fingers, fine section, and abundant juice; emits a strong fresh yam fragrance, without any odor. 4 points The epidermis is basically smooth, without wrinkles or mildew; the texture is relatively hard, with slight shallow indentation after pressing, the section texture is good, and the juice is sufficient; the yam fragrance is obvious, without any bad odor. 3 points The epidermis has a small amount of wrinkles, without mildew; the texture is medium, with obvious indentation after pressing, the section is slightly rough, and the juice is less; the fragrance is weak, with a slight storage smell, without any rotten odor. 2 points The epidermis is wrinkled, with mild mildew in some parts; the texture is soft, with obvious indentation after pressing, the section is fibrous, and the juice is very little; the fragrance is weak, with obvious storage smell, with a slight sour taste but no strong rotten smell. 1 point The epidermis is severely wrinkled and cracked; the texture is soft and rotten, with deep indentation and no rebound after pressing, the section is dry and hollow or paste-like; emits a strong rotten odor, such as sour smell, mildew smell, etc. The results are shown in Table 2: Table 2 Variety Treatment Number of investigations (roots) Sensory evaluation Rot index Preservation effect Xiaobaimouzhi yam Chinese herbal medicine extract 15 5 points 0% 53.33% Blank control 15 2.7 points 53.33% Local Ziyao Chinese herbal medicine extract 15 5 points 0% 10% Blank control 15 4.1 points 10% Yulinziyao Chinese herbal medicine extract 15 5 points 0% 6.67% Blank control 15 4.3 points 6.67% Shuangbang yam Chinese herbal medicine extract 15 5 points 0% 41.67% Blank control 15 3.8 points 41.67% Baiyushan yam Chinese herbal medicine extract 15 5 points 0% 68.33% Blank control 15 1.6 points 68.33% It can be seen that the sensory evaluation of the Dioscorea panthaica Prain var. sinica, Dioscorea panthaica Prain var. sinica, Dioscorea panthaica Prain var. sinica, Dioscorea panthaica Prain var. sinica, Dioscorea panthaica Prain var. sinica treated by the Chinese herbal medicine extract is 5 points, which is significantly higher than that of the blank control, indicating that the extract can effectively maintain the sensory quality of the Dioscorea panthaica Prain. The rot indexes of all the Dioscorea panthaica Prain treated by the Chinese herbal medicine extract are 0%, while the Dioscorea panthaica Prain of the blank control is rotten in different degrees, and the rot index is between 6.67%-68.33%, indicating that the extract can significantly inhibit the rot of the Dioscorea panthaica Prain during the storage period. In summary, the Chinese herbal medicine extract has a good effect in preventing and treating the diseases of the Dioscorea panthaica Prain during the storage period.

[0081] The above are preferred embodiments of the present application, not to limit the protection scope of the present application, therefore: all equivalent changes made according to the structure, shape, principle of the present application should be covered within the protection scope of the present application.

Claims

1. A method for preventing and controlling yam storage diseases based on Chinese herbal medicine extracts, characterized in that: The method of uniformly spraying Chinese herbal medicine extracts on the surface of Chinese yam to achieve freshness preservation and disease prevention during storage includes the following steps: Step 1, preparing a composite Chinese herbal extract, wherein the composite Chinese herbal extract comprises a fresh-keeping component and an antifungal spectrum component; Step 2, concentrating the compound Chinese herbal medicine extract under reduced pressure; Step 3, emulsifying and stabilizing the composite Chinese herbal medicine extract after reduced pressure concentration; Step 4, compounding the sustained-release film-forming agent with the emulsified and stabilized composite Chinese herbal medicine to obtain a compound liquid; Step 5: Remove the damaged, diseased tissue and dust on the surface of the yam; Step 6: Spray the diluted compound liquid on the surface of the yam.

2. The method for preventing and controlling yam storage diseases based on Chinese herbal medicine extracts according to claim 1, characterized in that: The compound Chinese herbal medicine extract comprises the following components: 90wt%-95wt% of a freshness-preserving component and 5wt%-10wt% of an antifungal spectrum component.

3. The method for preventing and controlling yam storage diseases based on Chinese herbal medicine extracts according to claim 2, characterized in that: The fresh-keeping component comprises the following components: 16 wt%-20 wt% of pomegranate peel, 16 wt%-20 wt% of phellodendron, 16 wt%-20 wt% of honeysuckle, 16 wt%-20 wt% of cnidium monnieri, and 16 wt%-20 wt% of houttuynia cordata; The antifungal spectrum components include the following components: 4wt%-6wt% of cloves and 2wt%-4wt% of mugwort.

4. The method for preventing and controlling yam storage diseases based on Chinese herbal medicine extracts according to claim 3, characterized in that: The sustained-release film-forming agent includes the following components: 0.2wt%-0.4wt% of chitosan, 0.05wt%-0.15wt% of citric acid, 0.5wt%-1.5wt% of glycerol, 18wt%-25wt% of 1% acetic acid solution, and 75wt%-80wt% of deionized water.

5. The method for preventing and controlling yam storage diseases based on Chinese herbal medicine extracts according to claim 4, characterized in that: In step 1, preparing the compound Chinese herbal medicine extract comprises the following steps: Step 11, mixing pomegranate peel, phellodendron, honeysuckle, cnidium monnieri, houttuynia cordata, cloves, and wormwood in proportions by weight, grinding into coarse powder with a grinder, and passing through a 20-30 mesh sieve to obtain a medicinal powder; Step 12: Add 4-5 times the amount of 99% alcohol to the powder, stir evenly and seal; Step 13: Soak in a 45-50 degree water bath for 6-10 hours, stirring 1-2 times per hour; Step 14, filtering with gauze or filter paper, collecting the filtrate to obtain the composite Chinese herbal medicine extract.

6. The method for preventing and controlling yam storage diseases based on Chinese herbal medicine extracts according to claim 5, characterized in that: In step 14, the filtered medicinal residues are added with 2-3 times the amount of 99% alcohol and soaked again for one more time, and all the filtrates are combined to obtain a composite Chinese herbal medicine extract.

7. The method for preventing and controlling yam storage diseases based on Chinese herbal medicine extracts according to claim 6, characterized in that: In step 3, a rotary evaporator is used for vacuum concentration, and a water temperature of 5-10° C. is passed through the condenser for circulating cooling. The compound Chinese herbal extract is poured into an eggplant-shaped bottle of the rotary evaporator, and the water bath temperature is set to 40-45° C. and the rotation speed is 50-60 r / min, and concentrated under reduced pressure; Keep observing the volume of the concentrate. When it is concentrated to 1 / 15-25 of the original filtrate volume, stop heating, close the vacuum valve, and take out the concentrate after the pressure is balanced. The concentrate was filtered through a 0.4 μm-0.5 μm microporous filter membrane to obtain a concentrated extract.

8. The method for preventing and controlling yam storage diseases based on Chinese herbal medicine extracts according to claim 7, characterized in that: Use a food-grade emulsifier compound system, add emulsifier at 1.0%-1.5% of the concentrated extract mass, pour the concentrated extract into the emulsification tank, start stirring at a speed of 800-1200r / min, slowly add the emulsifier, and stir for 3-6 minutes to achieve preliminary dispersion; Increase the speed to 2500-3500r / min, and at the same time, raise the water bath temperature to 50℃-55℃, and continue shearing and emulsification for 20-30 minutes to form a uniform emulsion; Turn off the heating, maintain the speed at 800-1200 r / min, cool to room temperature and stop stirring.

9. The method for preventing and controlling yam storage diseases based on Chinese herbal medicine extracts according to claim 8, characterized in that: In step 4, chitosan was weighed in parts by weight, slowly added to a 1% acetic acid solution, and stirred with a magnetic stirrer at a speed of 500-700 r / min for 25-35 minutes until completely dissolved to form a transparent chitosan solution; Add citric acid and glycerol to the chitosan solution in sequence and continue stirring for 10-20 minutes, wherein the citric acid is used to adjust the pH to 5.0-5.5; Add deionized water to the volume, stir evenly and let it stand for 25-35 minutes; The emulsified and stabilized compound Chinese herbal extract and the sustained-release film-forming agent are mixed in a volume ratio of 1:1 and poured into a mixing tank; stirring is started at a speed of 600-1000 r / min and stirred at room temperature for 15-25 minutes to form a uniform compound liquid.

10. The method for preventing and controlling yam storage diseases based on Chinese herbal medicine extracts according to claim 9, characterized in that: In step 6, adjust the dilution ratio according to the yam variety and storage period requirements: For short-term storage of less than or equal to 3 months, use a dilution factor of 900-1100 times; For long-term storage of more than 3 months, use a dilution factor of 400-600 times; Calculate the required volume of compound liquid and deionized water according to the dilution multiple, first add one-third of the volume of compound liquid and deionized water, stir at a speed of about 250-350r / min for 1-2 minutes; then slowly add the remaining two-thirds of the volume of compound liquid and deionized water, continue stirring for 2-3 minutes, until the solution is evenly diluted; use a high-pressure atomizing sprayer, rinse the nozzle with diluent in advance, spread the yam flat on a breathable grid rack, first spray the front for 20-40 seconds, let it stand for 1-3 minutes, then turn it over and spray the back for 20-40 seconds, and let the yam dry naturally for 3-4 hours after spraying.

Images