A kind of Morchella composite preservative and its application

Abstract

The present invention discloses a Morchella composite preservative and its application. The components of the Morchella composite preservative include 75 mg / L of surfactant, 25 mg / L of chitosan, 4000 mg / L of CaCl2, and 30% ethanol. The Morchella composite preservative can effectively inhibit fruiting body infection caused by the endophytic fungus Monosporus longisporus of Morchella during transportation and storage, improve the weight loss rate of Morchella, inhibit the browning of Morchella, and maintain the protein content and cell membrane integrity of Morchella, thereby indicating that the preservative has a good preservation effect on Morchella. The Morchella composite preservative of the present invention has safe and green raw materials, and provides a new idea for developing a safe, efficient, green and economical edible fungus preservation method.

Description

Technical Field

[0001] The invention belongs to the field of edible fungus preservation, and particularly relates to a morel composite preservative and application thereof. Background Art

[0002] Morel Morchella ) belongs to the Morchellaceae family and the genus Morchella, commonly known as Morchella, Yangque Mushroom, Corn Mushroom, and Lily Mushroom. Its ascocarp consists of a pointed or domed cap and a hollow stipe. It is a rare and valuable edible and medicinal fungus. Its fruiting bodies are rich in protein, amino acids, polysaccharides, vitamins, and trace elements, making them highly nutritious and delicious, making them a popular choice among consumers. In Traditional Chinese Medicine, Morchella fruiting bodies are used as a medicinal herb. They are mild in nature, slightly cold in flavor, and non-toxic. They are used to treat indigestion, excessive phlegm, and shortness of breath. They soothe the stomach, resolve phlegm, regulate qi, tonify the kidneys and enhance yang, and nourish the brain and invigorate the mind. Long-term consumption can prevent and fight cancer, inhibit tumors, prevent colds, and boost immunity.

[0003] In recent years, the artificial cultivation of Morchella has developed rapidly. However, the environmental conditions required for the growth of Morchella are very harsh, and it is impossible to achieve factory-scale production. The entire growth process from sowing to fruiting body maturity is in an open environment. Therefore, artificially cultivated Morchella is very susceptible to various fungal diseases. Morchella is very sensitive to pesticides. At present, the disease prevention and control measures in Morchella cultivation mainly focus on prevention. Diploöspora longispora ) is an endogenous pathogenic fungus of morels. Its hyphae are dense, white, and slightly raised. It can grow at temperatures between 4°C and 30°C, with an optimal temperature of 20°C. During production, transportation, and storage, once growth conditions are favorable, it can quickly infect the entire morel. Monoseptate oocystis primarily infects the ascocarps of morels, causing wilt and rot in the affected areas and deformed fruiting bodies. This fungal disease severely impacts the quality and yield of morels, reducing their commercial value and causing significant economic losses. It has been identified as a major pathogen in morel cultivation in Henan, Qinghai, Shandong, and Yunnan provinces in my country. In recent years, Monoseptate oocystis has become a serious fungal disease that has severely impacted the development of the morel industry. Fresh morels have a limited shelf life. Morchella fruiting bodies are hollow, and can be squeezed during storage and transportation, causing them to deform and rot. The endophytic fungus, Monosporus longisporus, can easily multiply and infect the entire morel. Furthermore, the high water content of the morel causes significant water loss through respiration and transpiration, reducing its nutritional value and severely degrading its quality during transportation and storage. Therefore, developing a safe and environmentally friendly preservative for morels is crucial. Summary of the Invention

[0004] The present invention aims to provide a Morchella composite preservative and its application. The Morchella composite preservative has safe and green raw materials, can inhibit fungi and has a good preservative effect on Morchella.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0006] The invention provides a morel composite preservative, the components of which include surfactin, chitosan, CaCl2 and ethanol.

[0007] Furthermore, the components of the Morchella composite preservative include 25 mg / L-75 mg / L of surfactin, 15 mg / L-75 mg / L of chitosan, 1000 mg / L-4000 mg / L of CaCl2, and 10%-40% ethanol.

[0008] Furthermore, the surfactant is obtained by fermenting, acidifying, drying and purifying Bacillus subtilis.

[0009] The invention also provides a morel preservation method, which comprises the following steps: selecting fresh morels with substantially uniform size, intact fruiting bodies and no ulceration, washing them with clean water, wiping off the moisture and air-drying them, and spraying the morel composite preservative on the caps and stems of the fresh morels.

[0010] Furthermore, the dosage of the Morchella composite preservative is 0.01 mL-1 mL.

[0011] The present invention also provides application of the Morchella composite preservative in improving the preservation effect of Morchella.

[0012] Furthermore, the composite preservative for morels improves the preservation effect of morels by improving the weight loss rate of morels and maintaining the protein content and cell membrane integrity of morels.

[0013] The present invention also provides application of the Morchella composite preservative in preparing an endogenous pathogenic fungus antibacterial agent.

[0014] Furthermore, the endopathogenic fungus is Monosporus longisporus.

[0015] The present invention also provides application of the Morchella composite preservative in preparing a Morchella browning agent.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] The present invention utilizes surfactant produced by Bacillus subtilis, which can inhibit the growth of Monosporus longisporus, the food-grade antibacterial agent chitosan, CaCl2, and ethanol to prepare a composite preservative for Morchella edulis that can effectively inhibit fungi. The optimal formulation is determined to be 75 mg / L of surfactant, 25 mg / L of chitosan, 4000 mg / L of CaCl2, and 30% ethanol. The composite preservative can improve the weight loss rate of Morchella edulis, inhibit browning of Morchella edulis, and maintain protein content and cell membrane integrity during refrigerated storage, further demonstrating that the preservative has a good preservative effect on Morchella edulis. The raw materials of the composite preservative for Morchella edulis are safe and green, providing new ideas for developing safe, efficient, green, and economical methods for preserving edible fungi. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The HPLC spectrum of surfactin produced by Bacillus subtilis and surfactin standard.

[0019] Figure 2 The inhibitory effect of surfactant produced by Bacillus subtilis on Monosporus longisporus.

[0020] Figure 3 is the inhibition rate of different antibacterial agents against Monosporus longisporus.

[0021] Figure 4 shows the inhibitory effect of spraying preservatives on Morchella infection with Monosporus longisporus; A is a solution mixed with Monosporus longisporus spores (1×10 7 ) preservative treatment group; B is the spore solution of Monosporus longisporus (1×10 7 ) treatment group.

[0022] Figure 5 The changes in weight loss rate of Morchella after treatment with different concentrations of preservatives.

[0023] Figure 6 The changes in the appearance of Morchella after treatment with preservatives at different concentrations.

[0024] Figure 7 The changes in the browning degree of Morchella after treatment with different concentrations of preservatives.

[0025] Figure 8 The changes in protein content of Morchella after treatment with different concentrations of preservatives.

[0026] Figure 9 The changes in electrical conductivity of Morchella after treatment with different concentrations of preservatives. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described in detail with reference to the following specific examples.

[0028] In the following examples, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used can be purchased from biological or chemical reagent companies. Example 1

[0029] 1. Bacteria activation

[0030] Prepare potato dextrose agar (PDA) medium: weigh 4.6 g of PDA powder and add it to 100 mL of distilled water. Sterilize by high-pressure steam at 115°C and set aside.

[0031] Remove the spore suspension of Monosporus longisporus from a -80°C freezer and thaw on ice. In a sterile laboratory, inoculate 0.2 mL of this suspension onto a PDA slant. Incubate in a 25°C incubator for 7 days, then transfer to a PDA plate and incubate at 25°C until ready for use. Transfer Morchella fungi from a 4°C freezer to a PDA plate in a sterile laboratory and incubate in a 25°C incubator for 3 days before use.

[0032] The strain of Monosporus longisporus was isolated and identified from Morchella fungi that were infected in the greenhouse of the Key Laboratory of Applied Fungi at Qingdao Agricultural University, where the Morchella fungi are kept.

[0033] 2. Inhibitory effect of surfactant produced by Bacillus subtilis on Monosporus longisporus

[0034] Bacillus subtilis is a strain preserved in the Key Laboratory of Applied Fungi at Qingdao Agricultural University. Surfactin is a mixture of four compounds obtained through laboratory fermentation. The preparation method of surfactin is as follows:

[0035] Activate Bacillus subtilis by streaking on a 37°C plate. Inoculate two loopfuls of the grown lawn into 50 mL of LB liquid seed medium and incubate at 37°C in a shaker for 24 hours. Transfer to fermentation medium and incubate at 170 rpm and 28°C for approximately 43 hours. Upon completion of fermentation, centrifuge at 8000 rpm at 4°C for 10 minutes and collect the supernatant. Add 6 M concentrated hydrochloric acid to the supernatant, stirring continuously, adjust the pH to 2.0, and refrigerate at 4°C overnight. Centrifuge at 8000 rpm at 4°C for 20 minutes, discard the supernatant, and collect the precipitate. Dissolve the precipitate thoroughly in sterile water, pre-cool at -80°C for 4 hours, and freeze-dry under vacuum for approximately 24 hours until completely dry. Collect the precipitate, dissolve it in an appropriate amount of chromatographic methanol, and store at 4°C until needed. The isolated surfactin was further separated and purified by preparative high performance liquid chromatography (HPLC). The preparative chromatographic column was YMC C18 column (10.0×250 mm, 5 μm), mobile phase A was ultrapure water + 0.1% trifluoroacetic acid, and mobile phase B was acetonitrile. Elution conditions were: mobile phase A was 10%, mobile phase B was 90%, elution time was 30 min, flow rate was 3 mL / min, column temperature was 30°C, injection volume was 200 μL, and UV detection wavelength was 210 nm. The purified surfactin contained four compounds S1, S2, S3, and S4, with relative contents of 16.67%, 19.51%, 20.23%, and 42.89%, respectively. The HPLC chromatograms of the purified surfactin and the surfactin standard are shown in Figure 2. Figure 1 .

[0036] Different concentrations of surfactant produced by Bacillus subtilis were added to PDA culture medium to prepare plates. A 5 mm diameter agar block of Monoseptate Sporangium longisporum was inoculated into the center of the culture medium. PDA culture medium without surfactant was used as a blank control. The plates were cultured at 25 ℃. The colony size of Monoseptate Sporangium longisporum was compared with that of the control to investigate the inhibitory effect of surfactant on Monoseptate Sporangium longisporum. Figure 2 As shown in the figure, when the concentration of surfactin in PDA was 40 mg / L, the inhibition rate against Monosporus longisporus was 24.05%, and when the concentration of surfactin was 100 mg / L, the inhibition rate was 85.17%. The inhibition rate was calculated as follows:

[0037]

[0038] 3. Inhibitory effects of different antibacterial agents on Monosporus longisporus

[0039] Agar plates containing different antibacterial agents were prepared by filtering and sterilizing natamycin, thiophanate-methyl, potassium sorbate, chitosan, and ClO₂ solutions at a concentration of 0.3 g / mL. 100 μL of each aliquot was added to 100 mL of PDA medium after filtration. A colony of Monoseptate spores was inoculated onto the center of the plate and incubated in a 25°C incubator. Colony diameters were measured using the cross-hatch method. The inhibition rate was calculated by comparison with the blank control group to identify the antibacterial agent with the most significant inhibitory effect on Monoseptate spores.

[0040]

[0041] Depend on Figure 3 As can be seen, all antibacterial agents exhibited some antibacterial activity, with the chitosan-added treatment group exhibiting the highest inhibition rate, followed by ClO2. Chitosan's inhibition rates were 43.95%, 34.23%, and 29.42% on days 2, 4, and 5, respectively. Starting on day 5, the chitosan inhibition rate decreased significantly, reaching 9.89% on day 7. These results demonstrate that chitosan exhibits a more pronounced inhibitory effect against Monosporus longisporus than other antibacterial agents. Therefore, chitosan was selected as the primary ingredient in the Morchella edodes preservative.

[0042] 4. Determination of preservative formula

[0043] The above experiments confirmed that the surfactant produced by Bacillus subtilis has a significant inhibitory effect on Monosporus longisporus. Using surfactant as the core ingredient of the preservative, a four-factor, three-level orthogonal experiment was designed (see Table 1) to determine the preservative formula.

[0044] Table 1 Orthogonal experiment factor level table

[0045]

[0046] Surfactant produced by Bacillus subtilis, chitosan, CaCl2, and ethanol were selected as the ingredients for a preservative for Morchella edulis. A four-factor, three-level orthogonal experiment was used to determine the optimal ratio of the preservative. The results are shown in Table 2. Nine treatment groups were divided, each corresponding to a different concentration of the preservative formulation. The preservative components of each formulation were mixed with PDA medium and poured into Petri dishes. The mixture was then inoculated with a colony of Monoseptate spores of Oodontoides. The culture was incubated in a dark incubator at 25°C for 21 days, and photographed. The diameter of the Oodontoides colonies was recorded, and the inhibition rate was calculated. Using the inhibition rate against Monoseptate spores as the evaluation indicator, range analysis results indicated that the optimal preservative formulation was A3B1C3D3. This preservative formulation for controlling the growth of endogenous pathogenic fungi during storage of Morchella edulis was: 75 mg / L surfactin, 25 mg / L chitosan, 4000 mg / L CaCl2, and 30% ethanol.

[0047] Table 2 Orthogonal experiment table and range analysis results

[0048]

[0049] 5. Spraying and preservation treatment of morels and index detection

[0050] 1) Experimental procedures

[0051] The preservative formulation was determined based on the results of a four-factor, three-level orthogonal experiment. Three concentration gradients were set to meet practical application requirements. Based on this formulation, 800 mL, 1500 mL, and 1000 mL of preservative were prepared, respectively: Group 1: 90 mg / L surfactin, 30 mg / L chitosan, 4800 mg / L CaCl₂, and 36% ethanol; Group 2: 55 mg / L surfactin, 18.3 mg / L chitosan, 2666 mg / L CaCl₂, and 20% ethanol; and Group 3: 75 mg / L surfactin, 25 mg / L chitosan, 4000 mg / L CaCl₂, and 30% ethanol. Fresh Morchella mushrooms of roughly uniform size, with intact fruiting bodies and no ulcers, were selected, washed with clean water, wiped with filter paper, and air-dried. Each treatment group sprayed 2 pumps of preservative on the front and back of the fresh morel cap and stem, and the control group sprayed an equal amount of distilled water. The morels were placed in food preservation bags and refrigerated at 4°C. The weight of the morels was measured every 24 hours and the weight loss rate was calculated. The physiological indicators of the samples were tested every 6 days.

[0052] (1) Inhibitory effect on Monosporus longisporus

[0053] In order to investigate the effect of preservatives on the prevention and control of Morchella oleracea infection by Monosporus longisporus, a spore solution of Monosporus longisporus (1×10 7 ), and mixed with spores of Monosporus longisporus (1×10 7 Morchella oleracea was treated with three groups of preservatives of different concentrations at 4°C for 12 days, and the incidence rate was investigated.

[0054] Incidence rate % = number of diseased Morchella / total number of treated Morchella × 100%

[0055] (2) Weight loss rate

[0056] Before the preservation treatment, the weight of the morels was weighed with an electronic balance. After the spraying, the weight was measured every 24 hours, and the weight loss rate was calculated by taking photos. The calculation formula of the weight loss rate of the morel sample is as follows, where: w o is the weight before treatment, w t is the weight after processing.

[0057]

[0058] (3) Browning degree: spectrophotometry

[0059] Take 2 g of the sample's stipe, add 5 mL of 80% ethanol solution, grind into a homogenate with liquid nitrogen, react at room temperature for 30 minutes, stir once every 5 minutes, and centrifuge in a high-speed refrigerated centrifuge at 4°C and 8000 rpm for 10 minutes. Use 80% ethanol as a blank control, take the supernatant and dilute it, and measure the absorbance value at 420 nm (the degree of browning is expressed as OD value).

[0060] (4) Protein content determination: BCA kit method (Shanghai Sangon Biotech Co., Ltd.)

[0061] Protein extraction: Take 0.5 g of sample, mince it, and add it to a 2 mL microcentrifuge tube. Add two 5 mm small steel balls and grind it using a tissue grinder. Quickly add 500 μl of 95°C preheated ST Buffer. Heat in a 95°C metal bath for 5 min. Gently shake, sonicate for 30 min, and centrifuge at 15,000 g for 10 min. Transfer the supernatant to a new 1.5 mL microcentrifuge tube to prepare the test solution.

[0062] Table 3 Kit composition

[0063]

[0064] Dilute 5× Solution A with distilled water to 1× Solution A. Based on the total volume of BCA working solution required, quantitatively dispense Solution A:Solution B at a ratio of 50:1 and mix thoroughly to prepare BCA working solution. Mix 1000 μL of distilled water and 1000 μL of Solution D to prepare Solution E. Dissolve 10 mg of Reagent C in 500 μL of Solution E and vortex for 1 minute to prepare Solution F.

[0065] Protein concentration test: Take 5 μl of the test solution and dilute it to 25 μl of sample diluent. Add 25 μl of solution F to the diluent, incubate at 37°C in a water bath for 30 min, add 1 mL of BCA working solution, mix quickly, and incubate at 37°C in a water bath for 30 min. After cooling to room temperature, measure the absorbance of each sample solution at 562 nm using a UV spectrophotometer and record it as A. 562 . Dilute each group of 3 samples with solution A 562 The average value of the value is substituted into the standard curve X = 68 × A 562 - 0.93 to calculate protein concentration, where X is the amount of protein in 1 mL reaction system / μg.

[0066] (5) Cell membrane integrity detection: conductivity method

[0067] Remove the morels from the fresh-keeping bag, rinse the preservative from the surface, rinse once with deionized water, and place on filter paper to air dry. Remove any surface moisture. Use a hole punch to create 15 discs of uniform thickness and size from the inner side of the cap. Place the discs in a beaker and add 50 mL of deionized water, ensuring the volume of the test solution is consistent across all treatment and control groups. Place the beaker in a vacuum desiccator and pump air for 20 minutes to remove air from the tissue cells. After removal, measure the conductivity of the control and treatment groups using a conductivity meter.

[0068] Use a conductivity meter to measure the conductivity of the test solution (L1). After the measurement, seal the sample solution with sealing film, boil it in a water bath for 30 minutes, cool it on ice for 10 minutes, and then measure the conductivity of each group (L2). Repeat the above operation and record the measured data. C )=L1 / L2×100%.

[0069] 2) Experimental results

[0070] (1) Inhibitory effect of spraying preservatives on Morchella longispora

[0071] During the transportation and storage of Morchella, the endophytic fungus Monosepta longispora will grow and reproduce rapidly as long as the conditions are suitable, and infect the fruiting body. This fungus is a low-temperature fungus and can grow and reproduce normally even at 4°C. In order to investigate the effect of preservatives on the prevention and control of Morchella infection with Monosepta longispora, a spore solution of Monosepta longispora (1×10 7 ), and mixed with spores of Monosporus longisporus (1×10 7 ) preservatives were used to treat Morchella oleracea and stored at 4°C for 12 days to investigate the morbidity.

[0072] The results are as follows Figure 4B The results showed that the Morchella edulis treated with the spore solution of Monoseptate Sporangium longisporium had different degrees of disease, with an incidence rate of 100%; the Morchella edulis treated with the spore solution of Monoseptate Sporangium longisporium (1×10 7 ) were treated with different concentrations of preservatives, none of the three groups of Morchella had disease and their fruiting bodies had good appearance ( Figure 4A This indicates that the three groups of preservatives with different concentrations can effectively control the infection of Morchella longispora during the storage process.

[0073] (2) Effect of spraying preservatives on the weight loss rate of morels

[0074] In order to investigate the effect of spraying preservatives on the moisture changes of Morchella edulis during cold storage, the fruiting bodies of Morchella edulis were treated with three concentration gradients of preservatives. The weight of Morchella edulis was measured every 24 h, and the weight loss rate was calculated after 20 days ( Figure 5 ).

[0075] like Figure 5 As shown, the weight loss rates of Groups 1, 2, and 3 were slightly lower than those of the control group during the 0th to 10th day of cold storage. The weight loss rate of Group 3 was the lowest during the 14th to 20th day of storage. Comprehensive analysis showed that the application of preservatives in each group had a certain effect on controlling weight loss during the first 12 days of storage. However, when the storage time was extended to 20 days, the weight loss rate of Group 1 increased significantly and was higher than that of the control group. The weight loss rates of Groups 2 and 3 were slightly lower than those of the control group, and Group 3 was lower than that of Group 2. Overall, the control effect of Group 3 was stronger than that of Groups 1 and 2.

[0076] (3) Effects of spraying preservatives on the appearance and browning degree of morels

[0077] In order to investigate the effect of spraying preservatives on the appearance and browning degree of Morchella fruiting bodies, photos were taken every day and the browning degree of Morchella stipes was tested every 6 days (the browning degree was expressed as OD value; the larger the OD value, the higher the browning degree). Figure 6 As shown, starting on the 6th day, the stipes of the control group began to yellow, while the treated groups remained in good condition. On the 12th day, the stipes of treatment groups 1 and 2 were slightly yellow but better than the control group, and the stipes of group 3 began to yellow. On the 18th day, the stipes of the control group began to turn brown and black, and the fruiting bodies began to rot. The browning began to become more serious in groups 1 and 2, with slight tissue fluid exudation and softened fruiting bodies, and the stipes of group 3 showed some yellowing. By the 20th day, the stipes of the control group had turned dark brown, and the fruiting bodies had rotted. Groups 1 and 2 had slight rot, and group 3 had the mildest symptoms.

[0078] like Figure 7 As shown, the browning degree of each treatment group increased during storage. On day 6, the browning degree of the control, groups 1, and 2 was approximately 0.32, while group 3 had a significantly lower browning degree than the other groups, at 0.145. From day 6 to 20, the browning degree of each treatment group was lower than that of the control group, with group 3 reaching its lowest level from day 6 to 18, reaching 0.559 on day 18. The browning degrees of the other groups were around 1.0. On day 20, the browning degrees of group 3 were slightly higher than the lowest value, group 1. In summary, all preservation treatments were effective in inhibiting browning of Morchella edulis, and overall, group 3 exhibited superior preservation performance to groups 1 and 2.

[0079] (4) Effect of spraying preservatives on the protein content of Morchella

[0080] In order to investigate the effect of fresh-keeping treatment on the crude protein content of Morchella during cold storage, samples were taken and treated, and the protein content was detected using a kit. Figure 8As shown, the crude protein content of Morchella edulis gradually decreased during cold storage, with the blank control group experiencing the most significant drop. All fresh-keeping treatments reduced nutrient loss during storage. On day 6, the protein content in Group 3 was significantly higher than in the other groups, reaching 5.898 μg / μL. On day 20, the protein content in all treatment groups remained between 2 and 3 μg / μL, with Group 3 achieving the highest value of 2.838 μg / μL. The control group, however, had a lower value than 1 μg / μL. Therefore, fresh-keeping treatments play a role in maintaining protein content in Morchella edulis during cold storage, with Group 3 showing the greatest effect.

[0081] (5) Effect of spraying preservatives on the integrity of Morchella cell membranes

[0082] The integrity of the cell membrane system reflects the stress resistance and degree of cell damage suffered during storage, thus reflecting the preservation quality of Morchella. The integrity of the cell membrane system is typically assessed by measuring the permeability of cell membrane ions. The degree of cell membrane permeability is determined by measuring the conductivity of the sample's aqueous extract. A high relative conductivity indicates severe damage to the cell membrane system. The lower the relative conductivity, the better the integrity of the cell membrane system, indicating that the preservative is more effective in preserving Morchella.

[0083] In order to investigate the effect of fresh-keeping treatment on the integrity of Morchella cell membrane, the conductivity of each sample was tested before and after boiling, and the relative conductivity was calculated. Figure 9 The relative conductivity of the Morchella mushrooms increased during cold storage in all groups, but the slowest increase was observed in Treatment 3. On day 6, the relative conductivity of Treatment 2 was 27.75%, the lowest of all groups; Group 3 (40.08%) was slightly higher than the control group (38.94%). However, from days 6 to 12, the relative conductivity of Group 2 increased dramatically, surpassing that of Group 3 from day 12 onward. From day 12 to 20, the relative conductivity of Group 3 remained at the lowest level. Overall, the application of preservatives in Groups 2 and 3 had a certain effect on maintaining the integrity of Morchella cell membranes, with Group 3 showing a stronger effect than Group 2.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions claimed to be protected by the present invention.

Claims

1. A composite preservative for Morchella esculenta, characterized in that: The morel composite preservative consists of 25 mg / L-75 mg / L of surfactin, 15 mg / L-75 mg / L of chitosan, 1000 mg / L-4000 mg / L of CaCl2 and 10%-40% ethanol.

2. The Morchella composite preservative according to claim 1, characterized in that The surfactant is obtained by fermenting, acid-lyzing, drying and purifying Bacillus subtilis.

3. A method for preserving morels, characterized in that: The preservation method comprises the following steps: selecting fresh morels of substantially uniform size, intact fruiting bodies and no ulceration, washing them with clean water, wiping off the moisture and air-drying them, and spraying the morel composite preservative according to claim 1 on the caps and stems of the fresh morels.

4. Use of the Morchella composite preservative according to claim 1 in improving the preservation effect of Morchella.

5. The use according to claim 4, characterized in that The composite preservative for morels improves the weight loss rate of morels and maintains the protein content and cell membrane integrity of morels, thereby improving the preservative effect of morels.

6. Use of the Morchella composite preservative according to claim 1 in the preparation of an endogenous pathogenic fungus antibacterial agent, characterized in that: The endopathogenic fungus is Monosporus longisporus.

7. Use of the Morchella composite preservative according to claim 1 in the preparation of a Morchella browning inhibitor.

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