A method for preventing and treating soft rot of agricultural products by fumigation

Abstract

This invention relates to the field of agricultural product storage, and more particularly to a fumigation method for preventing soft rot in agricultural products. The method involves fumigation using a cellulose-based material as a carrier, perillaldehyde and / or salicylaldehyde as a base, and the addition of isobutyric acid and / or 2-methylbutyric acid. This invention effectively inhibits and kills *Rhizopus spp.*, the pathogen causing soft rot in agricultural products, maintaining the physiological quality and nutritional value of agricultural products during storage, and significantly extending the storage period. This invention is highly effective, simple to operate, environmentally friendly and safe, and easily scaled up and industrialized.

Description

Technical Field

[0001] This invention relates to the field of agricultural product storage, and in particular to a fumigation method for preventing soft rot in agricultural products. Background Technology

[0002] Sweet potato (Ipomoea batatas [L.] Lam), belonging to the Convolvulaceae family and the Ipomoea genus, is also known as yam, sweet potato, red taro, and sweet potato. It is the world's seventh largest food crop. Sweet potatoes are rich in nutrients, containing various bioactive components with numerous health benefits, including antioxidant, liver-protective, anti-inflammatory, anti-tumor, anti-diabetic, antibacterial, anti-obesity, and anti-aging properties. It is a globally recognized nutritious food. However, the large size and thin skin of sweet potato tubers, coupled with rough harvesting methods and improper storage, make them highly susceptible to rotting during storage, resulting in significant losses.

[0003] Furthermore, the pathogens present during sweet potato storage are numerous and complex, and are related to factors such as seed potatoes, soil, and storage environment, making them very difficult to control. Among them, Rhizopus stolonifera, due to its strong reproductive capacity and rapid spread, makes soft rot the most significant factor affecting the quality deterioration of sweet potatoes during storage. Currently, post-harvest control of sweet potato soft rot mainly relies on the use of traditional fungicides. However, traditional fungicides leave harmful residues and increase pathogen resistance, thus necessitating the search for green and safe alternatives.

[0004] Based on the above problems, research on green and safe preservation methods has become a hot research direction in the field of postharvest preservation of agricultural products in recent years. Currently, there are studies on using perillaldehyde to inhibit the growth of *Botrytis cinerea* and *Fusarium oxysporum* tomato-specific strains (CN202210196652); perillaldehyde inhibiting the synthesis of ochratoxin A by *Aspergillus charcoalii* in fruits and vegetables and inhibiting the synthesis of the toxin *Alternaria alternata* (CN202211449887); and perillaldehyde combined with pyraclostrobin or difenoconazole as antibacterial active ingredients to inhibit the growth of *Colletotrichum spp.*, the anthracnose pathogen of tea trees (CN202211166320). However, there is still no good solution for fungal soft rot caused by *Rhizopus spp.*

[0005] Therefore, how to provide a green and safe preservation method to more effectively inhibit the growth of Rhizopus stolonifera and achieve the purpose of preventing soft rot of agricultural products and long-term storage and preservation remains a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the above technical problems, this invention provides a fumigation method for preventing soft rot in agricultural products.

[0007] Specifically, the fumigation method for preventing soft rot of agricultural products provided by the present invention includes fumigation with isobutyric acid and / or 2-methylbutyric acid, using cellulose-based material as carrier and perillaldehyde and / or salicylaldehyde as base.

[0008] Preferably, the fumigation method for preventing soft rot of agricultural products provided by the present invention uses perillaldehyde as a base and adds isobutyric acid for combined fumigation.

[0009] Preferably, the concentration of perillaldehyde is 2–80 μL / L and the concentration of isobutyric acid is 10–400 μL / L; more preferably, the concentration of perillaldehyde is 2–64 μL / L and the concentration of isobutyric acid is 10–320 μL / L; even more preferably, the concentration of perillaldehyde is 8 μL / L and the concentration of isobutyric acid is 160 μL / L.

[0010] Preferably, salicylaldehyde is used as a base, and 2-methylbutyric acid is added for combined fumigation.

[0011] Preferably, the concentration of salicylaldehyde is 1–20 μL / L and the concentration of 2-methylbutyric acid is 5–800 μL / L; more preferably, the concentration of salicylaldehyde is 1–16 μL / L and the concentration of 2-methylbutyric acid is 5–320 μL / L; even more preferably, the concentration of salicylaldehyde is 4 μL / L and the concentration of 2-methylbutyric acid is 160 μL / L.

[0012] This invention discovers that using perillaldehyde as a base and adding isobutyric acid for combined fumigation, or using salicylaldehyde as a base and adding 2-methylbutyric acid for combined fumigation, can reduce the concentration at which a single antibacterial agent exerts its antibacterial effect, thus achieving a synergistic effect.

[0013] The present invention further discovered that using perillaldehyde as a base and adding isobutyric acid for fumigation, or using salicylaldehyde as a base and adding 2-methylbutyric acid for fumigation, especially when the two are combined at specific concentrations, can cause leakage of intracellular substances in soft rot pathogens, increase cell membrane permeability, mycelial wall distortion and rupture, obvious plasmolysis, mitochondrial rupture, accumulation of endogenous reactive oxygen species, and decrease in mitochondrial membrane potential, thereby effectively inhibiting the growth of soft rot pathogens.

[0014] Preferably, the weight ratio of the cellulose-based material, perillaldehyde, to isobutyric acid is 0.5 to 4:1, and more preferably 1:1.

[0015] Preferably, the weight ratio of the cellulose-based material, salicylaldehyde, to 2-methylbutyric acid is 0.5 to 4:1, and more preferably 1:1.

[0016] Further preferably, the cellulose-based material includes cotton fibers and / or microcrystalline cellulose, preferably cotton fibers.

[0017] In this invention, the agricultural products are treated using the fumigation method after harvesting.

[0018] According to the present invention, the pathogen causing soft rot includes, but is not limited to, Rhizopus creepingus. The fumigation method for controlling soft rot in agricultural products described in this invention is applicable to soft rot caused by all pathogens, and is particularly effective in controlling soft rot caused by Rhizopus creepingus.

[0019] In this invention, the agricultural products referred to are sweet potatoes, potatoes, and other agricultural products that are easily infected and spoiled by pathogens including Rhizopus stolonifer. However, this invention is not limited to these. The fumigation method for preventing soft rot in agricultural products described in this invention is applicable to all soft rot diseases caused by pathogens such as Rhizopus stolonifer, and is particularly effective in preventing soft rot in sweet potatoes caused by Rhizopus stolonifer.

[0020] The beneficial effects of this invention are at least as follows:

[0021] (1) This invention uses cellulose-based materials as carriers, which have good adsorption properties and can achieve good loading of perillaldehyde and isobutyric acid, and salicylaldehyde and 2-methylbutyric acid. At the same time, cellulose-based materials have the advantages of being inexpensive, readily available, safe and non-toxic, environmentally friendly, easily biodegradable and renewable, making them suitable for large-scale applications.

[0022] (2) The combined fumigation of perillaldehyde and isobutyric acid, and the combined fumigation of salicylaldehyde and 2-methylbutyric acid provided by this invention have strong synergistic antibacterial effects. Compared with single fumigation, they can more effectively inhibit the growth of Rhizopus spp., the pathogen of soft rot, and improve the control effect on soft rot of agricultural products. At the same time, they overcome the problems of increased drug resistance, pesticide residues, and environmental pollution caused by the excessive reliance on chemical fungicides in traditional preservation methods.

[0023] (3) The fumigation method for preventing soft rot of agricultural products provided by the present invention does not come into direct contact with agricultural products, is green and safe, leaves no residue and causes no pollution, is simple to operate, has a good antibacterial effect, and is easy to promote in industrialization. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 The diagram shows the effect of the fumigation method provided in this embodiment of the invention on the inhibition of sweet potato soft rot disease. Detailed Implementation

[0026] To clearly illustrate the content of this invention, a detailed description will be provided below. The following embodiments and comparative examples are used to illustrate the invention, but are not intended to limit its scope. To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below.

[0027] Unless otherwise specified, specific techniques or conditions in the embodiments shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. The implementation conditions in the embodiments may be further adjusted according to specific experimental or factory conditions. Unspecified implementation conditions are generally those used in routine experiments. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art, and all raw materials used are commercially available products.

[0028] Unless otherwise specified, the percentage sign "%" used in this invention refers to volume percentage.

[0029] The microorganism involved in the examples, Rhizopus cremastogyne (CICC40327), is a pathogen that causes sweet potato soft rot and was obtained from the China Industrial Microbial Culture Collection Center.

[0030] The culture media involved in the examples, namely potato dextrose agar (PDA) medium and potato dextrose broth (PDB) medium, were obtained from Beijing Aoboxing Biotechnology Co., Ltd.

[0031] The sweet potatoes used in this example were "Pushu 32" variety sweet potatoes harvested from local farms in Beijing. Fruits free from pests and diseases, mechanical damage, similar size, and uniform maturity were selected.

[0032] In the following embodiments, the storage conditions are a storage temperature of 12°C and a storage humidity of 85%.

[0033] In the following examples, the weight ratio of cotton fiber: perillaldehyde to isobutyric acid in Examples 1-2 and Comparative Examples 1-2 is 1:1; the weight ratio of cotton fiber: salicylaldehyde to 2-methylbutyric acid in Examples 3-4 and Comparative Examples 3-4 is 1:1.

[0034] Example 1

[0035] This embodiment provides a fumigation method for preventing soft rot in agricultural products. The agricultural products are fumigated using cotton fiber as a carrier, perillaldehyde as a base, and isobutyric acid as a co-fumigation agent. The concentration of perillaldehyde is 8 μL / L and the concentration of isobutyric acid is 160 μL / L.

[0036] Example 2

[0037] This embodiment provides a fumigation method for preventing soft rot in agricultural products. The agricultural products are fumigated using cotton fiber as a carrier, perillaldehyde as a base, and isobutyric acid as a co-fumigation agent. The concentration of perillaldehyde is 16 μL / L and the concentration of isobutyric acid is 160 μL / L.

[0038] Example 3

[0039] This embodiment provides a fumigation method for preventing soft rot in agricultural products. The agricultural products are fumigated using cotton fiber as a carrier, salicylaldehyde as a base, and 2-methylbutyric acid as a co-fumigation agent. The concentration of salicylaldehyde is 4 μL / L and the concentration of 2-methylbutyric acid is 160 μL / L.

[0040] Example 4

[0041] This embodiment provides a fumigation method for preventing soft rot in agricultural products. The agricultural products are fumigated using cotton fiber as a carrier, salicylaldehyde as a base, and 2-methylbutyric acid as a co-fumigation agent. The concentration of salicylaldehyde is 2 μL / L and the concentration of 2-methylbutyric acid is 160 μL / L.

[0042] Comparative Example 1

[0043] This comparative example provides a fumigation method for preventing soft rot in agricultural products. The agricultural products are fumigated using cotton fiber as a carrier and perillaldehyde as a base, without the addition of isobutyric acid. The concentration of perillaldehyde is 8 μL / L and the concentration of isobutyric acid is 0 μL / L.

[0044] Comparative Example 2

[0045] This comparative example provides a fumigation method for preventing soft rot in agricultural products. The agricultural products are fumigated using cotton fiber as a carrier, without perillaldehyde as a base, and isobutyric acid is added for combined fumigation. The concentration of perillaldehyde is 0 μL / L, and the concentration of isobutyric acid is 160 μL / L.

[0046] Comparative Example 3

[0047] This comparative example provides a fumigation method for preventing soft rot in agricultural products. The agricultural products are fumigated using cotton fiber as a carrier and salicylaldehyde as a base, without the addition of 2-methylbutyric acid. The concentration of salicylaldehyde is 4 μL / L and the concentration of 2-methylbutyric acid is 0 μL / L.

[0048] Comparative Example 4

[0049] This comparative example provides a fumigation method for preventing soft rot in agricultural products. The agricultural products are fumigated using cotton fiber as a carrier, without salicylaldehyde as a base, and 2-methylbutyric acid is added for combined fumigation. The concentration of salicylaldehyde is 0 μL / L, and the concentration of 2-methylbutyric acid is 160 μL / L.

[0050] Comparative Example 5

[0051] This comparative example involves storing freshly harvested sweet potatoes that are free from pests, diseases, and mechanical damage directly in the warehouse.

[0052] Experimental Example 1: Evaluation of the inhibitory effect of combined fumigation on the growth of pathogenic fungus Rhizopus stolonifera mycelium.

[0053] In this experimental example, a plate test was used to measure the results of the above embodiments and comparative examples.

[0054] 1. Activate *Rhizopus stolonifer* on PDA medium at 28°C for 5 days. Then, add 5 mL of sterile water to a petri dish, obtain a fungal suspension by scraping the colonies with a scraper, and filter twice to obtain a spore suspension. Prepare a 1×10⁻⁶ spore suspension using a hemocytometer. 8 A spore suspension of spores / mL was thoroughly shaken on a vortex mixer for later use.

[0055] 2. Take 5 μL of 1×10 6 Spores / mL of *Rhizopus spores* suspension were spotted onto Type I plates. Using cotton fibers as a carrier, different concentrations of perillaldehyde or salicylaldehyde were added dropwise onto the fibers. After thorough wetting, different concentrations of isobutyric acid or 2-methylbutyric acid were added for fumigation. After incubation at 28°C for 48 h, mycelial growth was measured, and the inhibition rate was calculated. Each treatment was replicated five times. The results are shown in Table 1.

[0056] Table 1. Inhibition rate of combined fumigation on Rhizopus spp.

[0057]

[0058]

[0059] The results showed that fumigation with perillaldehyde and isobutyric acid, and fumigation with salicylaldehyde and 2-methylbutyric acid had a synergistic effect and could significantly inhibit the growth of Rhizopus stolonifera.

[0060] Experimental Example 2: Evaluation of the inhibitory effect of combined fumigation on Rhizopus stolonifer in sweet potato

[0061] 1. Activate *Rhizopus stolonifer* on PDA medium at 28℃ for 5 days. Then, add 5 mL of sterile water to a petri dish, obtain a fungal suspension by scraping the colonies with a scraper, and filter twice to obtain a spore suspension. Prepare a 1×10⁻⁶ spore suspension using a hemocytometer. 8 A spore suspension of spores / mL was thoroughly shaken on a vortex mixer for later use.

[0062] 2. Select sweet potatoes that are uniform in maturity and size, and free from mechanical damage. Rinse them with tap water and air dry them. Then, surface disinfect them with 75% alcohol for 2 minutes and air dry them at room temperature. Make three 5mm deep micro-wounds on one side of each sweet potato and inject 20μL of 1×10 [agent / treatment] into each wound. 6 Spores / mL of Rhizopus spp. suspension.

[0063] Sweet potatoes cultured for 24 hours were treated in three groups: a) Directly placed in a plastic storage box (with gauze at the bottom and covered with gauze to maintain moisture) and stored at 28℃. b) The sweet potatoes were subjected to fumigation using cotton fiber as a carrier, perillaldehyde as a base, and isobutyric acid as a combined fumigation agent. The concentrations of perillaldehyde and isobutyric acid were 8 μL / L and 160 μL / L, respectively. They were then placed in a plastic storage box (with gauze at the bottom and covered with gauze to maintain moisture) and stored at 28℃. c) The sweet potatoes were subjected to fumigation using cotton fiber as a carrier, salicylaldehyde as a base, and 2-methylbutyric acid as a combined fumigation agent. The concentrations of salicylaldehyde and 2-methylbutyric acid were 4 μL / L and 160 μL / L, respectively. They were then placed in a plastic storage box (with gauze at the bottom and covered with gauze to maintain moisture) and stored at 28℃. Disease incidence was recorded by photograph at regular intervals. The experiment was repeated three times.

[0064] The effects of combined fumigation on sweet potato inoculated with Rhizopus stolonifera, such as Figure 1 As shown in the figure, sample a softened and rotted after 15 days of storage, exhibiting typical symptoms of soft rot. Samples b and c, however, showed small local scabs on the puncture wounds after 15 days of storage, with no further infection observed. The results indicate that fumigation with perillaldehyde and isobutyric acid, and fumigation with salicylaldehyde and 2-methylbutyric acid, can effectively prevent the spread of Rhizopus stolonifer.

[0065] Experiment Example 3: Phenylalanine ammonia-lyase (PAL) activity experiment

[0066] PAL plays an important role in plant resistance. Its activity was determined by using a PAL kit to compare the preservation effects on sweet potatoes in different examples and comparative examples. The results are shown in Table 2.

[0067] Table 2. PAL activity values ​​of sweet potatoes after 60 days of storage.

[0068]

[0069] The results show that the combined fumigation with perillaldehyde and isobutyric acid, and the combined fumigation with salicylaldehyde and 2-methylbutyric acid provided by the present invention can significantly improve the resistance of sweet potatoes, thereby effectively extending the storage time of sweet potatoes.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fumigation method for preventing soft rot in agricultural products, characterized in that, This includes using cellulose-based materials as carriers, perillaldehyde as a base, and isobutyric acid added for combined fumigation, with perillaldehyde concentration of 8 μL / L and isobutyric acid concentration of 160 μL / L; or using salicylaldehyde as a base and 2-methylbutyric acid added for combined fumigation, with salicylaldehyde concentration of 4 μL / L and 2-methylbutyric acid concentration of 160 μL / L.

2. The fumigation method for preventing soft rot in agricultural products according to claim 1, characterized in that, The weight ratio of perillaldehyde to isobutyric acid in the cellulose-based material is 0.5 to 4:

1.

3. The fumigation method for preventing soft rot in agricultural products according to claim 1, characterized in that, The weight ratio of the cellulose-based material salicylaldehyde to 2-methylbutyric acid is 0.5 to 4:

1.

4. The fumigation method for preventing soft rot in agricultural products according to any one of claims 1 to 3, characterized in that, The cellulose-based material includes cotton fibers and / or microcrystalline cellulose.

5. The fumigation method for preventing soft rot of agricultural products according to any one of claims 1 to 3, characterized in that, After the agricultural products are harvested, they are treated using the described fumigation method.

6. The fumigation method for preventing soft rot of agricultural products according to any one of claims 1 to 3, characterized in that, The pathogen causing soft rot includes Rhizopus cremastogyne; and / or, the agricultural products include sweet potatoes and potatoes.

Images