Method for preventing and treating postharvest diseases of tomatoes with kojic acid and for storage and preservation

Abstract

The invention belongs to the technical field of biological prevention and treatment of postharvest diseases, and particularly relates to a method for preventing and treating postharvest diseases of tomatoes with kojic acid and for storage and preservation. The method comprises the following steps: preparing a kojic acid solution, and sterilizing for later use; then, punching holes in the surfaces of the tomatoes, injecting the holes into the tomatoes, standing, and injecting the same volume of pectobacterium carotovorum suspension, so that the soft rot caused by the pectobacterium carotovorum is effectively controlled; or taking tomatoes in a natural state, soaking the tomatoes in a kojic acid solution, and naturally airing the tomatoes to realize the purposes of disease control, storage and fresh-keeping of the picked tomatoes. The method can significantly reduce the occurrence of soft rot after tomato harvesting, reduces the natural rotting rate after tomato harvesting, is safe and environmentally friendly, has no significant adverse effect on the main quality indexes of the harvested tomatoes, can slow down the deterioration of the storage quality of the tomatoes, achieves significant technical effects, and has wide application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of biological control of postharvest diseases, and particularly relates to a method for controlling postharvest diseases of tomatoes with kojic acid and storing and preserving tomatoes. Background Art

[0002] Tomato (Solanum lycopersicum L.) is a crop of the genus Solanaceae and an important vegetable crop. Tomato has high nutritional value and contains rich active ingredients such as organic acids, vitamins, carotenoids, etc. However, tomatoes are very susceptible to infection by pathogens and rot during planting and storage, which seriously affects the yield and commercial value of tomatoes and causes huge economic losses.

[0003] The main post-harvest diseases of tomatoes include gray mold, black spot and soft rot, among which soft rot is the most important bacterial disease. Tomato soft rot is caused by Pectobacterium carotovora, which mainly harms the stems and fruits of tomatoes. Tomatoes can be infected from the growth period to the storage period. After invading, Pectobacterium carotovora secretes pectinase, which dissolves the middle gelatin layer between host cells and separates cells, causing soft rot and loss of edible value. Therefore, it is very important to adopt safe and effective methods to control post-harvest soft rot of tomatoes.

[0004] At present, the methods for controlling post-harvest diseases of fruits and vegetables mainly include physical methods, chemical methods and biological control methods. Physical methods mainly control the occurrence of diseases through methods such as high temperature, low temperature, vacuum, irradiation or gas conditioning. This method is safe, non-toxic and harmless, but some physical measures are costly and consume a lot of energy. Some treatment methods will have adverse effects on the sensory quality of tomatoes. Chemical methods usually use chemical fungicides such as chlorpyrifos, pyrimethanil and chlorothalonil to control post-harvest diseases of fruits and vegetables. This method is low in cost, quick in effect and simple to operate. However, the long-term and large-scale use of chemical fungicides is prone to produce resistant strains, causing ecological environmental pollution, and chemical fungicide residues will also cause serious harm to the health of consumers. Biological control methods use the interaction between certain organisms or the metabolites (natural compounds) of organisms to inhibit the growth of pathogens, thereby achieving the purpose of controlling post-harvest diseases of fruits and vegetables. Compared with physical and chemical methods, biological control methods have the advantages of safety, non-toxicity, and green environmental protection.

[0005] Natural compounds are classified into plant, animal and microbial sources according to their sources. Plant-derived natural compounds include essential oils and spices. Animal-derived natural compounds include chitosan and propolis. Microbial-derived natural compounds include secondary metabolites and organic acids, such as nisin and natamycin, and kojic acid. Studies have found that natural compounds inhibit the proliferation of pathogens mainly through two pathways: one is to destroy the cell wall and cell membrane structure of pathogens, change the morphology of bacteria, and affect cell permeability; the other is to interfere with the expression of pathogen-related proteins and signal transduction.

[0006] Kojic acid is an organic acid with bactericidal effects produced by microbial fermentation under aerobic conditions. It appears as light yellow needle-shaped crystals, has good water solubility, high thermal stability, and is harmless to the human body when ingested. However, there are currently few reports on the application of kojic acid in the prevention and control of post-harvest diseases and storage and preservation of fruits and vegetables. Summary of the invention

[0007] The present invention applies kojic acid to the prevention and treatment of tomato postharvest diseases and storage and preservation of tomatoes, which can effectively control the occurrence of tomato postharvest diseases and reduce the losses caused by postharvest diseases. Studies have shown that kojic acid can significantly reduce the occurrence of postharvest soft rot of tomatoes, and soaking in kojic acid can reduce the natural decay of tomatoes after harvest, has no significant adverse effect on tomato quality, and can slow down the deterioration of its quality, thereby achieving the purpose of tomato storage and preservation, and has potential application value.

[0008] To achieve the above purpose, the present invention provides the following solutions:

[0009] The method for preventing and controlling postharvest soft rot of tomatoes with kojic acid and storing and preserving tomatoes provided by the present invention is carried out according to the following steps:

[0010] (1) firstly prepare a kojic acid solution, dissolve solid kojic acid evenly in water to obtain a kojic acid solution, and sterilize the solution for later use;

[0011] (2) selecting tomatoes without diseases, mechanical damage, uniform color and size, disinfecting their surfaces, and then washing them with running water. After the washed tomatoes are air-dried, a sterile punch is used to punch holes at the equator of the tomatoes to form wounds of a certain depth, and the kojic acid solution prepared in step (1) is added to the wounds. After standing for a period of time, a suspension of Pectinobacterium carotovorax is inoculated. After natural drying, the suspensions are sealed with plastic wrap and placed in a constant temperature and humidity incubator for storage to achieve control of postharvest soft rot of tomatoes;

[0012] Alternatively, tomatoes without diseases, mechanical damage, uniform color and similar size are selected, and the tomatoes are kept in their natural state without any disinfection treatment. The tomatoes are soaked in the kojic acid solution prepared in step (1), and after soaking, the tomatoes are taken out and placed in a sterilized plastic basket. After natural drying, the plastic basket is sealed with plastic wrap and stored in a constant temperature and humidity incubator, thereby achieving the purpose of preventing and controlling post-harvest diseases of tomatoes and storing and preserving them.

[0013] Preferably, the purity of the solid kojic acid in step (1) is ≥98%; and the concentration of the kojic acid solution is 3-5 mg / mL.

[0014] Preferably, the sterilization conditions in step (1) are: 121° C., 20 min.

[0015] Preferably, the operation of disinfecting the surface of tomatoes in step (2) is: immersing the tomatoes in a 2% sodium hypochlorite solution for disinfection for 2-5 minutes; the disinfection of the plastic basket is to clean it and then dry it, then spray it evenly with 75% alcohol for disinfection, and irradiate it with ultraviolet light overnight.

[0016] Preferably, the wound in step (2) has a diameter of 4 mm and a depth of 4 mm.

[0017] Preferably, in step (2), 20 μL of kojic acid solution and suspension of Pectinobacterium carotii soft rot are added to each wound; the standing period is 2 h; the concentration of the suspension of Pectinobacterium carotii soft rot is 1×10 6 CFU / mL.

[0018] Preferably, the culture temperature in the constant temperature and humidity incubator in step (2) is 20° C. and the relative humidity is 90%.

[0019] Preferably, in step (2), the tomatoes are soaked in the kojic acid solution, and the specific operation is: the kojic acid solution is completely immersed in the whole tomato, and the soaking time is 3-5 minutes.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] (1) The kojic acid used in the present invention is a natural metabolite of aerobic fermentation of microorganisms. It has many unique uses in the fields of food, cosmetics, agriculture, etc. Traditional fermented foods such as soy sauce, vinegar, and soybean paste will produce kojic acid during the fermentation process, which is safe and non-toxic to the human body. At the same time, it has an inhibitory effect on a variety of bacteria, especially Gram-negative bacteria, and also has the effects of anti-oxidation and inhibiting enzymatic browning.

[0022] (2) The present invention utilizes kojic acid to treat tomatoes, which can significantly reduce the occurrence of postharvest soft rot of tomatoes, reduce the natural decay rate of postharvest tomatoes, and reduce the losses caused by soft rot, thus having good market application prospects.

[0023] (3) Compared with the control, the kojic acid treatment of postharvest tomatoes used in the present invention has no significant adverse effects on the main quality indicators of postharvest tomatoes, such as weight loss rate, hardness, soluble solids, titratable acid, ascorbic acid, lycopene and browning degree, and can alleviate the quality deterioration of tomatoes during storage, which is beneficial to the storage and preservation of tomatoes.

[0024] (4) The present invention uses the natural compound kojic acid to replace chemical fungicides to prevent and control post-harvest diseases of tomatoes. It can be used for storage and preservation of post-harvest tomatoes, which can reduce the harm of chemical fungicides to the health of consumers and the environment, and has the advantage of being green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The control effect of different concentrations of kojic acid on postharvest soft rot of tomatoes; (A): rot rate, (B): rot diameter; CK is the control group, i.e. tomatoes treated with sterile water; 3mg / mL, 4mg / mL, 5mg / mL are tomatoes treated with 3mg / mL, 4mg / mL, 5mg / mL kojic acid respectively; the concentration of Pectobacterium carotovorax soft rot is 1×10 6 CFU / mL; Different lowercase letters represent significant differences (P<0.05).

[0026] Figure 2 Figure (A) shows the control effect of kojic acid on the natural decay of tomatoes; (B) is hardness, (C) is weight loss rate, (D) is soluble solids, (E) is titratable acid, (F) is ascorbic acid, (G) is browning degree, and (H) is lycopene; Note: CK is the control group, i.e. tomatoes treated with sterile water; KA is tomatoes treated with 4 mg / mL kojic acid; "*" indicates significant difference (P < 0.05); "**" indicates extremely significant difference (P < 0.01). DETAILED DESCRIPTION

[0027] The present invention is explained in more detail by means of the following embodiments. The following embodiments are merely illustrative and the present invention is not limited to these embodiments.

[0028] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art in the art to which the present invention relates.

[0029] Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe methods and / or materials related to the documents. The raw materials, reagents, etc. used in the present invention can be obtained through conventional channels such as commercially available unless otherwise specified. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0030] The activation steps of carrot soft rot pectin bacteria before use are as follows:

[0031] (1) First activation: Pectinobacterium carotovora stored in a glycerol tube at -80°C was inoculated into 50 mL of LB medium and cultured at 37°C and 180 rpm for 12 h to perform the first activation and obtain a culture solution;

[0032] (2) Secondary activation: Use a sterilized pipette tip to draw 1 mL of the activated culture solution into another 50 mL bottle of LB medium and culture at 37°C and 180 rpm for 12 h to obtain the culture solution;

[0033] (3) Centrifugation and resuspension: The culture solution in (2) was centrifuged at 4°C and 8000 rpm for 10 min, and the precipitate was washed twice with sterile saline to remove the culture matrix to obtain bacterial sludge, which was then resuspended with sterile saline and adjusted to the desired bacterial solution concentration (1×10 6 CFU / mL).

[0034] Embodiment 1:

[0035] Kojic acid is used to control postharvest soft rot in tomatoes;

[0036] 1. Experimental plan

[0037] Select tomatoes without disease, mechanical damage, uniform color and size, soak them in 2% sodium hypochlorite solution for 3 minutes, then rinse with running water, and put the washed tomatoes in a sterilized plastic basket to dry. Use a sterile punch to make three equally spaced 4mm×4mm (diameter×depth) wounds along the equator of the dried tomatoes, and do the following treatment: add 20μL of kojic acid solution (concentrations are 3mg / mL, 4mg / mL, and 5mg / mL, respectively) to each wound. After leaving at room temperature for 2h, add 20μL of carrot soft rot pectinobacterium suspension (1×10 6 CFU / mL); after drying at room temperature, place in a constant temperature and humidity incubator (20°C, relative humidity 90%) for 5 days. During storage, the tomato rot rate was counted and the rot diameter was measured with a vernier caliper. Sterile water was used instead of kojic acid-treated tomatoes as the control group. Each treatment was repeated 3 times, with 12 tomatoes in each parallel.

[0038] Decay rate = number of rotten holes / total number of holes × 100%.

[0039] 2. Test results

[0040] Depend on Figure 1 As shown in (A), after 1 day of storage, the tomatoes in the control group and those treated with different concentrations of kojic acid did not rot; after 2-4 days of storage, the rot rates of tomatoes treated with different concentrations of kojic acid were significantly lower than those in the control group (p<0.05), and the rot rates decreased with the increase of kojic acid concentration; after 5 days of storage, the rot rates of tomatoes treated with 4 mg / mL and 5 mg / mL kojic acid concentrations were significantly lower than those in the control group (p<0.05), but there was no significant difference between the two concentration treatment groups.

[0041] Depend on Figure 1 As shown in (B), after 2 days of storage, the rot diameter of tomatoes treated with different concentrations of kojic acid had no significant difference from that of the control group; after 3-5 days of storage, the rot diameter of tomatoes treated with 4 mg / mL kojic acid was the lowest, which was significantly different from the control group and the 3 mg / mL kojic acid treatment group (p<0.05), and after 3 and 5 days, the rot diameter of tomatoes treated with 4 mg / mL kojic acid was also significantly different from that of the 5 mg / mL kojic acid treatment group (p<0.05).

[0042] Taking into account the effects of different concentrations of kojic acid treatment on the rot rate and rot diameter of tomatoes, 4 mg / mL kojic acid can be selected for the prevention and control of tomato soft rot, which has a significant effect.

[0043] Embodiment 2:

[0044] Kojic acid is used for storage and preservation of tomatoes;

[0045] 1. Experimental plan

[0046] Tomatoes without disease, mechanical damage, uniform color and size were selected. No disinfection was performed and the tomatoes were kept in their natural state. The tomatoes were fully soaked in (1) sterile water; (2) kojic acid solution (kojic acid concentration was 4 mg / mL and sterilized in advance), and placed in a sterilized plastic basket. After the tomatoes were naturally dried, the plastic basket was sealed with plastic wrap and placed in a constant temperature and humidity incubator (relative humidity 90%) for 20 days. During the storage period, the natural decay rate of the tomatoes was counted, and the changes in tomato hardness, weight loss rate, soluble solids, titratable acid content, ascorbic acid content, browning degree and lycopene content were measured. Each treatment was repeated 3 times, and each parallel had 12 tomatoes.

[0047] Natural decay rate (%) = number of rotten fruits / total number of fruits × 100%

[0048] The specific determination methods of quality indicators are as follows:

[0049] 1. Hardness: Use TA-XT2i physical property analyzer to measure the hardness of tomatoes. Use a probe with a diameter of 5 mm and a probe model of P5. Randomly select 6 tomato samples from each group of samples, select 2 different points at the equator for testing, and measure a total of 12 points. Take the maximum value of each measurement as the hardness (N), and finally calculate the average value.

[0050] Texture analyzer parameter selection: select extrusion mode as the operating mode, force sensor range 1000N, probe recovery distance 30mm, pre-measurement rate 4.0mm / s, measurement rate 1.0mm / s, post-measurement rate 5.0mm / s, record the peak force during the entire test process, the unit is N.

[0051] 2. Weight loss rate: Weight loss rate = (mass before treatment - mass after storage) / mass before treatment × 100%

[0052] 3. Soluble solid content: Use a handheld refractometer to measure the soluble solid content (%) of tomato fruit at room temperature. Adjust the refractometer to zero with distilled water before use. Weigh about 5.0g of tomato pulp, mash it in a mortar, grind it into a pulp, place it at 4°C, 8000rpm, centrifuge it for 10 minutes, take the supernatant, and use a handheld refractometer to measure the soluble solid content of the tomato.

[0053] 4. Titratable acid content: Determine by sodium hydroxide titration. Weigh about 5.0g of sample, add appropriate amount of distilled water, grind into a homogenate in a mortar, transfer to a 50mL centrifuge tube and let stand for 30min, shaking every 10min. Centrifuge at 4℃, 8000rpm for 10min, transfer the supernatant to a 50mL volumetric flask, dilute to the scale, and shake well. Pipette 10mL of sample solution into a conical flask, add 2 drops of 1% phenolphthalein, and titrate with 0.1mol / L NaOH. Titrate until the solution begins to show light pink and does not fade within 30s. Distilled water is used as the blank control, and the results are expressed as mass fraction (%).

[0054] Titratable acid content (%) = (V×c×(V1-V0)×0.067) / (Vs×m)×100%

[0055] Where V is the total volume of the sample extract (mL), c is the NaOH concentration (mol / L), V1 is the volume of sodium hydroxide solution consumed in titrating the sample solution (mL), V0 is the volume of sodium hydroxide solution consumed in titrating distilled water (mL), Vs is the volume of the sample solution taken during titration (mL), m is the sample mass (g), and 0.067 is the malic acid conversion coefficient (g / mmol).

[0056] 5. Ascorbic acid content: Determine by 2,6-dichlorophenol indophenol titration method. Weigh about 5.0g tomato tissue sample and place it in a mortar, add appropriate amount of 20g / L oxalic acid solution and quartz sand, place it in a mortar under light-proof and ice-bath conditions, grind it into a homogenate, and transfer it to a 50mL centrifuge tube. Centrifuge for 10min at 4℃ and 8000rpm, transfer the supernatant to a 50mL brown volumetric flask and dilute to the scale, shake well. Take 10mL of sample solution in a conical flask, titrate the sample solution with the calibrated 2,6-dichlorophenol indophenol solution until a slightly reddish color appears and does not fade for 30s, which is the titration end point. At the same time, use 10mL of 20g / L oxalic acid solution as a blank control. According to the amount of 2,6-dichlorophenol indophenol, calculate the ascorbic acid content in tomatoes, expressed as the mass of ascorbic acid contained in each kilogram of sample, that is, mg / 100g.

[0057] Titer T = (c × V) / (V1-V0)

[0058] Where c is the mass concentration of ascorbic acid standard solution (mg / mL), V is the volume of ascorbic acid standard solution absorbed (mL), V1 is the volume of 2,6-dichlorophenol indophenol solution consumed when titrating the standard liquid (mL), and V0 is the volume of 2,6-dichlorophenol indophenol solution consumed when titrating the blank (20g / L oxalic acid) (mL).

[0059] Ascorbic acid content (mg / 100g) = [V×(V1-V0)×T] / (Vs×m)×100

[0060] Where V is the total volume of the sample extraction solution (mL), V1 is the volume of the dye consumed in the sample titration (mL), V0 is the volume of the dye consumed in the blank titration (mL), Vs is the volume of the sample solution taken during the titration (mL), and m is the sample mass (g).

[0061] 6. Browning degree: Weigh about 5.0g of pulp and pound it in a mortar. Grind it into a slurry, place it at 4℃, 8000rpm, centrifuge it for 10min, take the supernatant for direct measurement, and use the absorbance value at 420nm to directly indicate the browning degree.

[0062] 7. Lycopene: petroleum ether extraction method. Weigh about 5.0g of tomato pulp, add 25mL of distilled water and place in a mortar, grind to homogenate in a light-proof ice bath, transfer to a separatory funnel, add 25mL of petroleum ether, mix thoroughly, let stand for 30 minutes, separate, take the upper layer, and measure its absorbance (A) at 472nm.

[0063] Lycopene content (mg / 100g) = (c ’ ×V) / (m×10)

[0064] where c ’is the lycopene concentration obtained from the standard curve (μg / mL), V is the total volume of the extract (mL), and m is the sample mass (g).

[0065] 2. Test results

[0066] Depend on Figure 2 As can be seen in Figure A, during the storage of tomatoes, the rot rate of tomatoes treated with kojic acid was significantly lower than that of the control group at 5, 10 and 15 days. At 20 days of storage, the rot rate of tomatoes treated with kojic acid (36.11%) was significantly lower than that of the control group (72.22%) (p<0.05); thus, kojic acid can significantly reduce the natural rot rate of post-harvest tomatoes. Therefore, kojic acid has a good preventive effect on post-harvest natural rot of tomatoes.

[0067] Depend on Figure 2 As can be seen from Figure B, during the postharvest storage of tomatoes, the hardness of the tomatoes in the two treatments showed the same trend of change, both showing a trend of continuous decrease with the increase of storage time, and there was no significant difference between the treatment group and the control group. This shows that kojic acid has no significant adverse effect on the hardness of tomatoes after harvest.

[0068] Depend on Figure 2 As shown in Figure C, the weight loss rate of tomatoes treated with different treatments increased with the extension of storage time, but kojic acid treatment can reduce the loss of water in tomatoes. Therefore, during the entire storage process, the weight loss rate of tomatoes in the kojic acid treatment group was lower than that in the control group. Especially in the late storage period (15 days and 20 days), the respiration of tomatoes was enhanced, and the water loss of tomatoes in the control group was large after harvest, while the weight loss rate of the kojic acid treatment group was significantly lower than that of the control group (p<0.05), indicating that kojic acid can inhibit the loss of water in tomatoes and reduce the weight loss rate of tomatoes after harvest.

[0069] Depend on Figure 2 As can be seen from Figure D, during the postharvest storage process, the overall change trend of the soluble solids content of the two groups of tomatoes is basically the same. Except for the 15th day, the kojic acid treatment group is higher than the control group, but there is no significant difference between the two. This shows that the kojic acid of the patent application has no significant adverse effect on the soluble solids content of postharvest tomatoes, and can increase its soluble solids content during storage to a certain extent.

[0070] Depend on Figure 2 It can be seen from Figure E that during the postharvest storage of tomatoes, the overall trend of titratable acid content in the control group and the kojic acid-treated tomatoes was basically the same, and there was no significant difference between the two groups. This indicates that kojic acid has no significant adverse effect on the titratable acid content of postharvest tomatoes.

[0071] Depend on Figure 2It can be seen from the figure that during the postharvest storage of tomatoes, the ascorbic acid content of the control group and the kojic acid-treated tomatoes did not change significantly, and there was no significant difference between the two groups, indicating that kojic acid had no significant adverse effect on the ascorbic acid content of postharvest tomatoes.

[0072] Depend on Figure 2 As can be seen from Figure G, during the entire storage process, the overall trend of the browning degree of tomatoes in the control group and kojic acid treatment was gradually increasing with time, but the kojic acid treatment group was always significantly lower than the control group (p<0.05). It may be that kojic acid inhibits enzymatic browning and thus reduces the browning degree of tomatoes.

[0073] Depend on Figure 2 It can be seen from the figure that during the storage of tomatoes, the lycopene content increases with the extension of storage time. Because the tomatoes used in the experiment are hard-ripening fruits, they will gradually mature during storage, so the lycopene content gradually increases. Except for 15 days, there is no significant difference between the treatment group and the control group. Therefore, kojic acid has no significant adverse effect on the lycopene content of post-harvest tomatoes, and can increase its content at 15 days.

[0074] In summary, kojic acid has a good preventive effect on the natural decay of tomatoes, has no significant adverse effect on tomato quality, and can alleviate the deterioration of tomato quality to a certain extent, and can be used for the storage and preservation of post-harvest tomatoes.

[0075] Note: The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention; therefore, although this specification has described the present invention in detail with reference to the above embodiments, a person skilled in the art should understand that the present invention can still be modified or replaced by equivalents; and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for preventing and controlling postharvest diseases of tomatoes and storing and preserving tomatoes using kojic acid, characterized in that: The specific steps are as follows: (1) firstly prepare a kojic acid solution, dissolve solid kojic acid evenly in water to obtain a kojic acid solution, and sterilize the solution for later use; (2) selecting tomatoes without diseases, mechanical damage, uniform color and size, disinfecting their surfaces, and then washing them with running water. After the washed tomatoes are air-dried, a sterile punch is used to punch holes at the equator of the tomatoes to form wounds of a certain depth, and the kojic acid solution prepared in step (1) is added to the wounds. After standing for a period of time, a suspension of Pectinobacterium carotovorax is inoculated. After natural drying, the suspensions are sealed with plastic wrap and placed in a constant temperature and humidity incubator for storage to achieve control of postharvest soft rot of tomatoes; Alternatively, tomatoes without diseases, mechanical damage, uniform color and similar size are selected, and the tomatoes are kept in their natural state without any disinfection treatment. The tomatoes are soaked in the kojic acid solution prepared in step (1), and after soaking, the tomatoes are taken out and placed in a sterilized plastic basket. After natural drying, the plastic basket is sealed with plastic wrap and stored in a constant temperature and humidity incubator, thereby achieving the purpose of preventing and controlling post-harvest diseases of tomatoes and storing and preserving them.

2. The method for using kojic acid in the prevention and treatment of postharvest diseases of tomatoes and the storage and preservation of tomatoes according to claim 1, characterized in that: The purity of the solid kojic acid in step (1) is ≥98%; the concentration of the kojic acid solution is 3-5 mg / mL.

3. The method for preventing and controlling postharvest diseases of tomatoes and storing and preserving tomatoes using kojic acid according to claim 2, characterized in that: The concentration of the kojic acid solution in step (1) is 4 mg / mL.

4. The method for preventing and controlling postharvest diseases of tomatoes and storing and preserving tomatoes using kojic acid according to claim 1, characterized in that: The sterilization conditions in step (1) are: 121° C., 20 min.

5. The method for preventing and controlling postharvest diseases of tomatoes and storing and preserving tomatoes using kojic acid according to claim 1, characterized in that: The operation of tomato surface disinfection in step (2) is: immersing the tomatoes in 2% sodium hypochlorite solution for disinfection for 2-5 minutes; the plastic basket disinfection is to clean and dry it, then spray it evenly with 75% alcohol for disinfection, and irradiate it with ultraviolet light overnight.

6. The method for preventing and controlling postharvest diseases of tomatoes and storing and preserving tomatoes using kojic acid according to claim 1, characterized in that: The hole diameter of the punching in step (2) is 4 mm and the depth is 4 mm.

7. The method for preventing and controlling postharvest diseases of tomatoes and storing and preserving tomatoes using kojic acid according to claim 1, characterized in that: In step (2), 20 μL of kojic acid solution and suspension of Pectinobacterium carotovora were added to each wound; and the standing period was 2 hours.

8. The method for preventing and controlling postharvest diseases of tomatoes and storing and preserving tomatoes using kojic acid according to claim 1, characterized in that: The concentration of the bacterial suspension of Pectinobacterium carotovora in step (2) is 1×10 6 CFU / mL.

9. The method for preventing and controlling postharvest diseases of tomatoes and storing and preserving tomatoes using kojic acid according to claim 1, characterized in that: The temperature of the culture in the constant temperature and humidity incubator in step (2) is 20° C. and the relative humidity is 90%.

10. The method for preventing and controlling postharvest diseases of tomatoes and storing and preserving tomatoes using kojic acid according to claim 1, characterized in that: In step (2), the tomatoes are soaked in the kojic acid solution, specifically, the kojic acid is required to immerse the entire tomato, and the soaking time is 3-5 minutes.

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