Fresh-keeping method for dictyophora rubrovolvata by combining ultraviolet with controlled atmosphere

Abstract

The invention discloses a fresh-keeping method for dictyophora rubrovolvata by combining ultraviolet with controlled atmosphere, and belongs to the technical field of edible mushroom fresh-keeping. In order to solve the problems that dictyophora rubrovolvata is prone to water loss, browning and microbial infection after being picked and an existing preservation technology is poor in effect, the method comprises the steps that dictyophora rubrovolvata is harvested from the egg-shaped period to the mushroom skirt half-expansion period, after rinsing is conducted for 1-2 minutes through a 0.5-1.0% sterile salt solution at the temperature of 1-7 DEG C, rapid blow-drying is conducted through circulating cold air at the temperature of 4-6 DEG C and the air speed of 2-3 m / s, and the temperature of the center of a mushroom body is reduced to 8-10 DEG C within 30 minutes; performing normal-temperature irradiation for 20-30 minutes by short-wave ultraviolet rays with the dominant wavelength of 254 nm; and immediately loading into a preservation box, injecting a mixed gas of 3-5% of oxygen, 5-15% of carbon dioxide and the balance of nitrogen, and storing at 0-4 DEG C. Through the synergistic effect of ultraviolet and controlled atmosphere, respiratory metabolism, browning and microbial growth of dictyophora indusiata are remarkably inhibited, the preservation period is prolonged to 12 days or above, the color, crisp and tender texture and nutritional ingredients of dictyophora indusiata can be kept, no chemical residues exist, operation is easy and convenient, cost is low, and the method is suitable for factory-like preservation and logistics.

Description

Technical Field

[0001] This invention belongs to the field of edible fungi preservation, specifically relating to a method for preserving red-topped bamboo fungus using ultraviolet light combined with modified atmosphere packaging. Background Technology

[0002] Red-topped bamboo fungus (Dictyophora rubrovalvata) is a valuable edible fungus, prized for its delicious flavor and rich content of polysaccharides, amino acids, and minerals, giving it high economic and nutritional value. However, red-topped bamboo fungus experiences vigorous respiration and high water content after harvesting, making it highly susceptible to dehydration, browning, cap opening, and microbial contamination. These issues lead to a rapid decline in its commercial value and severely restrict the large-scale development of the red-topped bamboo fungus industry.

[0003] Existing preservation technologies for red-topped bamboo fungus have many shortcomings: low-temperature refrigeration is a common preservation method, but the preservation period is only 2-4 days, which cannot meet the needs of long-distance transportation and long-term storage; although chemical preservatives can extend the shelf life to a certain extent, there is a risk of chemical residues, which affects food safety and consumer health; simple modified atmosphere packaging technology is prone to problems such as anaerobic respiration due to inaccurate control of gas ratios, and tissue poisoning due to excessively low oxygen concentration, which can accelerate quality deterioration; ultraviolet irradiation, as a physical sterilization technology, can effectively inhibit microorganisms and induce plant resistance, but when used alone, its penetration is weak, and it can only achieve surface treatment. It cannot act on the inside of food or the shaded areas of food with complex shapes, and it does not have a sustained sterilization effect. After the treatment, the food is easily recontaminated and may also accelerate lipid / protein oxidation, causing food discoloration, off-flavors, or damage to plant tissues.

[0004] Therefore, developing a synergistic preservation method combining ultraviolet light and modified atmosphere packaging to overcome the limitations of existing technologies and achieve complementary advantages is of great significance for improving the post-harvest quality of red-topped bamboo fungus and extending its shelf life. Summary of the Invention

[0005] To address the problems of short shelf life, easy quality deterioration, and safety risks in existing red-topped bamboo fungus preservation technologies, this application designs a method for preserving red-topped bamboo fungus using ultraviolet light combined with modified atmosphere packaging. Through the synergistic effect of ultraviolet pretreatment and modified atmosphere packaging, the respiration, microbial growth, and enzymatic browning of red-topped bamboo fungus are significantly inhibited, extending the shelf life while maintaining its nutritional components and product quality. Furthermore, the method is simple to operate, low in cost, and leaves no chemical residues, making it suitable for industrial preservation and logistics.

[0006] A method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging includes the following steps: Step S1, Harvesting and Pretreatment: Harvest the fruiting bodies of red-capped bamboo fungus from the oval stage to the half-expanded stage of the veil. Within 2 hours after harvesting, clean and remove the residual veil and impurities. Gently rinse the cleaned red-capped bamboo fungus in a sterile salt solution, then remove it and place it in a high-intensity circulating cold air to quickly dry the surface moisture, so that the temperature of the core of the fungus drops to 8-10℃ within 30 minutes. Step S2, UV irradiation treatment: The surface-dried pre-cooled red bamboo fungus is laid in a single layer on a clean bench and irradiated through a closed channel equipped with a short-wave ultraviolet irradiation device. The irradiation process is carried out at room temperature. Step S3, Modified Atmosphere Packaging: Immediately after UV irradiation, the red-topped bamboo fungus is placed into a preservation box, and a mixed gas is injected into the preservation box to form a modified atmosphere. The mixed gas has an oxygen concentration of 3%-5%, a carbon dioxide concentration of 5%-15%, and the remaining gas is nitrogen. Step S4, Storage: Store the modified atmosphere packaged red bamboo fungus in an environment of 0-4℃.

[0007] Preferably, in step S1, the red-topped bamboo fungus is harvested during the oval stage, when the veil is not broken. At this stage, the fruiting bodies of the red-topped bamboo fungus are at a suitable maturity, have strong storage resistance, and can better maintain their quality in the subsequent preservation process.

[0008] Preferably, in step S1, the mass fraction of the sterile salt solution is 0.5~1.0%, and the temperature is 1~7℃. The low-temperature salt solution can not only remove impurities from the surface of bamboo fungus, but also use the low-temperature environment to initially slow down the decay and deterioration rate of bamboo fungus. Preferably, the sterile salt solution has a mass fraction of 0.7% and a temperature of 3°C. This combination of parameters can ensure the cleaning effect while minimizing damage to the bamboo fungus tissue.

[0009] Preferably, in step S1, the rinsing time is 1 to 2 minutes, which can not only fully remove surface impurities and some microorganisms, but also avoid prolonged soaking that would cause the bamboo fungus to absorb too much water and reduce its quality.

[0010] Preferably, in step S1, the temperature of the high-intensity circulating cold air is 4~6℃ and the wind speed is 2~3m / s, which can quickly dry the surface moisture of the bamboo fungus, reduce the core temperature of the fungus, and inhibit respiration and metabolism; more preferably, the temperature of the high-intensity circulating cold air is 5℃ and the wind speed is 2.5m / s, which has high cooling efficiency and can maintain the crisp and tender texture of the bamboo fungus.

[0011] Preferably, in step S2, the cumulative effective irradiation time is 20 minutes, and the ultraviolet irradiation dose is 0.8~1.5 kJ / m²; or the cumulative effective irradiation time is 25~30 minutes. The ozone generated during ultraviolet irradiation can work synergistically with ultraviolet light to effectively remove microorganisms on the surface of bamboo fungus, and room temperature irradiation can prevent the mushroom body temperature from rising and causing quality deterioration; experimental verification shows that the number of colonies is the lowest and the sterilization effect is the best when ultraviolet irradiation lasts for 25 minutes.

[0012] Preferably, in step S2, the main wavelength of the short-wave ultraviolet light is 254nm. Ultraviolet light of this wavelength has high sterilization efficiency and can effectively destroy the DNA / RNA structure of microorganisms to achieve sterilization. At the same time, it can induce bamboo fungus to develop resistance and improve the preservation effect.

[0013] Preferably, in step S3, the mixed gas consists of 5% oxygen, 8% carbon dioxide, and 87% nitrogen. This gas ratio can effectively inhibit the respiration intensity and enzyme activity of bamboo fungus. When the volume ratio of carbon dioxide to oxygen is approximately 2:1, the effect on maintaining the quality of bamboo fungus is optimal. The modified atmosphere environment maintains a stable gas concentration through spontaneous modified atmosphere technology, ensuring that the gas ratio remains within the ideal range during the preservation process.

[0014] The advantages and effects of this application are as follows: This application presents a method for preserving red-topped bamboo fungus using a combination of ultraviolet (UV) and modified atmosphere packaging. By combining UV-C pretreatment with modified atmosphere packaging, UV irradiation achieves initial sterilization and induces resistance in the bamboo fungus, while the modified atmosphere environment continuously inhibits respiratory metabolism and microbial growth. The synergistic effect of these two methods solves the problems of insufficient sustained effect from single UV treatment and inadequate sterilization from single modified atmosphere packaging. It effectively inhibits enzymatic browning and weight loss, maintaining the color and crisp texture of the bamboo fungus. Simultaneously, it maintains the content of soluble solids, soluble protein, and other nutrients, and the vitamin D3 content remains at a high level during storage, reaching a peak on day 6 and significantly exceeding that of the single-treatment group, thus significantly improving the preservation effect. The entire preservation process involves no added chemical preservatives, avoiding the risk of chemical residues and meeting food safety requirements. The operation is simple, the required equipment is readily available, and the cost is controllable, making it suitable for the industrial-scale preservation and logistics of red-topped bamboo fungus. Experiments show that this method can extend the shelf life of red-topped bamboo fungus to more than 12 days under 0~4℃ conditions, far exceeding the existing low-temperature refrigeration of 2~4 days, thus meeting the needs of long-distance transportation and long-term storage.

[0015] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the preferred embodiments of this application are described in detail below with reference to the accompanying drawings.

[0016] The above and other objects, advantages and features of this application will become more apparent to those skilled in the art from the following detailed description of specific embodiments in conjunction with the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0018] Figure 1 A graph showing the changes in bacterial colonies on plates after different UV irradiation times; Figure 2 A graph showing the changes in soluble solids content of bamboo fungus under different treatment methods; Figure 3 A graph showing the changes in soluble protein content in bamboo fungus under different treatment methods; Figure 4 A graph showing the changes in catalase (CAT) activity in bamboo fungus under different treatments; Figure 5 A graph showing the changes in polyphenol oxidase (PPO) activity in bamboo fungus under different treatments; Figure 6 A graph showing the changes in peroxidase (POD) activity in bamboo fungus under different treatments; Figure 7 A graph showing the changes in superoxide dismutase (SOD) activity in bamboo fungus under different treatments; Figure 8 Graphs showing the changes in browning degree of bamboo fungus under different treatments; Figure 9 A graph showing the change in weight loss rate of bamboo fungus under different treatment methods; Figure 10 A graph showing the changes in vitamin D3 content in bamboo fungus under different treatment methods. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. In the following description, specific details such as specific configurations and components are provided merely to help fully understand the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.

[0020] It should be understood that the phrase "an embodiment" or "this embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "an embodiment" or "this embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0021] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.

[0022] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. The term " / and" in this article describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone. In addition, the character " / " in this article generally indicates that the related objects before and after it are in an "or" relationship.

[0023] In this article, the term "at least one" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, "at least one of A and B" can mean: A exists alone, A and B exist simultaneously, or B exists alone.

[0024] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion.

[0025] Example 1: This example mainly introduces the design of a method for preserving red-topped bamboo fungus by combining ultraviolet light with modified atmosphere packaging through specific embodiments.

[0026] Experimental materials: Fresh red-topped bamboo fungus that are uniform in size, undamaged, and free from pests and diseases were selected and harvested during the oval stage, when the veil was not broken.

[0027] Grouping: Red-topped bamboo fungus was randomly divided into four groups, with 30 samples in each group: Group A (method of the present invention), Group B (modified atmosphere treatment only), Group C (ultraviolet irradiation treatment only), and Group D (no treatment, blank control).

[0028] Processing steps: Group A: Step S1, Harvesting and Pretreatment: Within 1.5 hours after harvesting, clean and remove residual volva and impurities. Place the cleaned red volva bamboo fungus in a sterile salt solution with a mass fraction of 0.7% and a temperature of 3°C and gently rinse for 1.5 minutes. After taking it out, place it in a high-intensity circulating cold air at a temperature of 5°C and a wind speed of 2.5m / s to quickly dry the surface moisture. Within 25 minutes, the temperature of the core of the fungus will drop to 9°C. Step S2, UV irradiation treatment: The surface-dried pre-cooled red bamboo fungus is laid in a single layer on a clean bench and irradiated through a closed channel equipped with a short-wave ultraviolet irradiation device with a main wavelength of 254nm. The cumulative effective irradiation time is 20 minutes, the irradiation dose is 1.0kJ / m², and the irradiation process is carried out at room temperature. Step S3, Modified Atmosphere Packaging: Immediately after UV irradiation, the red-topped bamboo fungus is placed into a sealed preservation box, and a mixed gas (5% oxygen, 8% carbon dioxide, 87% nitrogen) is injected into the preservation box to maintain a stable gas concentration through self-generated modified atmosphere technology. Step S4, Storage: Store the modified atmosphere packaged red bamboo fungus in a 4℃ cold storage.

[0029] Group B: Step S1, Harvesting and Pretreatment: Same as Step S1 in Group A; Step S2: No ultraviolet irradiation treatment is performed; Step S3, Modified Atmosphere Packaging: Same as Step S3 in Group A; Step S4, Storage: Same as step S4 in group A.

[0030] Group C: Step S1, Harvesting and Pretreatment: Same as Step S1 in Group A; Step S2, UV irradiation treatment: Same as step S2 in group A; Step S3: Without modified atmosphere packaging, directly pack into a regular food storage container and seal. Step S4, Storage: Same as step S4 in group A.

[0031] Group D: Step S1, Harvesting and Pre-treatment: Only remove residual mycelium and impurities; do not rinse or dry in cold air. Step S2: No ultraviolet irradiation treatment is performed; Step S3: Directly pack into a regular food storage container and seal. Step S4, Storage: Same as step S4 in group A.

[0032] Example 2: Performance Testing and Result Analysis For the four groups of red-topped bamboo fungus in Example 1, various quality indicators were measured every 3 days. The detection methods and results are as follows: Microbial testing: The number of surface microorganisms was determined using the plate count method. Results showed that the colony count in group A was significantly lower than that in groups B, C, and D after 12 days of storage. Figure 1 (Graph showing changes in bacterial colonies on plates after different UV irradiation times) The graph includes images of bacterial colonies of *Dictyophora indicum* after 25 min of UV irradiation (diluted 10-1000 times from left to right), 20 min, and 15 min. It is clearly visible that the number of colonies is the lowest and the bactericidal effect is the best after 25 min of UV irradiation, which confirms that the synergistic effect of UV and modified atmosphere can effectively inhibit the growth of microorganisms.

[0033] Soluble solids content detection: A handheld refractometer was used for measurement. The results showed that the soluble solids content of groups A and B (modified atmosphere treatment groups) was consistently higher than that of the non-modified atmosphere group, reaching its peak on day 3. Group A maintained this effect better than group B. Figure 2 (The graph shows the changes in soluble solids content of bamboo fungus under different treatment methods. The horizontal axis represents storage time (days), and the vertical axis represents soluble solids content. The curve "ck" represents the blank control group (group D), "UV" represents the UV irradiation group only (group C), "modified atmosphere" represents the modified atmosphere treatment group only (group B), and "modified atmosphere + UV" represents the method of this invention group (group A). ​​It can be seen that the modified atmosphere environment can delay the loss of nutrients, and the UV pretreatment further enhances this effect.

[0034] Soluble protein content detection: The Coomassie brilliant blue method was used for determination. The results showed that the soluble protein content generally increased first and then decreased. Group A (modified atmosphere + UV treatment group) maintained the best soluble protein content, reaching its peak on day 3, significantly higher than the other three groups. Figure 3 (The graph shows the changes in soluble protein content of bamboo fungus under different treatment methods. The horizontal axis represents storage time (days), and the vertical axis represents soluble protein content. The trends of each group of curves are consistent with the test results, clearly reflecting the effect of the method of the present invention on the preservation of protein components.

[0035] Enzyme activity assay: The activities of catalase (CAT), polyphenol oxidase (PPO), peroxidase (POD), and superoxide dismutase (SOD) were measured using kits provided by Suzhou Keming. CAT activity: CAT activity in groups A and B (modified atmosphere treatment groups) remained stable, significantly better than the drastic fluctuations in the control group. Group A showed the best effect, effectively reducing intracellular oxidative stress. Figure 4 (The graph shows the changes in catalase (CAT) activity in bamboo fungus under different treatments. The curves of each group show significant differences, and the modified atmosphere + ultraviolet treatment group has the best CAT activity stability. PPO activity: The PPO activity of groups A and B (modified atmosphere treatment groups) was significantly lower than that of the non-modified atmosphere treatment group, and group A (modified atmosphere + UV) showed better results, effectively inhibiting browning caused by the oxidation of phenolic compounds. Figure 5 (The graph shows the changes in polyphenol oxidase (PPO) activity in bamboo fungus under different treatments. The PPO activity curve of the modified atmosphere + ultraviolet treatment group was always at the lowest level, and the browning inhibition effect was clearly visible.) POD activity: The POD activity of the modified atmosphere treatment group was higher than that of the non-modified atmosphere treatment group. Group A (modified atmosphere + UV) showed the best results, effectively catalyzing the decomposition of peroxides and avoiding cell damage. Figure 6 (The graph shows the changes in peroxidase (POD) activity in bamboo fungus under different treatments. The modified atmosphere + ultraviolet treatment group showed the highest POD activity curve, indicating a significant cell protection effect.) SOD activity: Enzyme activity initially increased and then decreased. The activity in the modified atmosphere treatment group was higher than that in the non-modified atmosphere group. Group A maintained the highest activity on day 12, effectively reducing superoxide toxicity. Figure 7 (The graph shows the changes in superoxide dismutase (SOD) activity in bamboo fungus under different treatments. The SOD activity in the modified atmosphere + ultraviolet treatment group remained at the optimal level throughout the entire storage period.)

[0036] Browning degree detection: Spectrophotometer measurements were used. Results showed that the browning degree of the modified atmosphere treatment groups (Groups A and B) was significantly lower than that of the non-modified atmosphere treatment groups (Groups C and D), indicating that modified atmosphere treatment effectively slows down the browning of bamboo fungus. The synergistic effect of UV pretreatment and modified atmosphere treatment further optimized this effect. Figure 8 (The graph shows the browning degree of bamboo fungus under different treatments.) As shown, the browning degree curve of the modified atmosphere treatment group is always lower than that of the non-modified atmosphere group, and the differences between the groups are clearly distinguishable.

[0037] Weight loss rate detection: The weight loss rate was determined using a weighing method. Results showed that the weight loss rate of the modified atmosphere packaging groups (Group A and Group B) was significantly lower than that of the non-modified atmosphere packaging group, confirming that modified atmosphere packaging can effectively reduce moisture loss from bamboo fungus and maintain the weight of the mushroom. Figure 9(The graph shows the weight loss rate of bamboo fungus under different treatment methods.) The weight loss rate curves of the modified atmosphere + ultraviolet treatment group and the modified atmosphere only treatment group are basically the same and at a low level, indicating a significant effect in moisture retention.

[0038] Vitamin D3 content detection: High-performance liquid chromatography (HPLC) was used for determination. The results showed that vitamin D3 content initially increased and then decreased. Group A reached its peak on day 6, significantly higher than the other three groups, and maintained the highest content on day 12, indicating that the method of this invention can effectively preserve the nutritional components of bamboo fungus. Figure 10 (The graph shows the changes in vitamin D3 content in bamboo fungus under different treatments.) The modified atmosphere + ultraviolet treatment group had the highest peak vitamin D3 content curve and a slow decline in the later stage, indicating the best nutrient retention effect.

[0039] Example 3: Based on Examples 1 and 2, this example mainly introduces the effect verification of different parameter combinations.

[0040] Experimental groups with different parameter combinations were set up to verify the rationality of each parameter in the technical solution of this invention: Sterile saline solution parameters: mass fractions of 0.5%, 0.7%, and 0.9%, and temperatures of 2℃, 3℃, and 5℃ were set respectively. The results showed that the bamboo fungus was cleaned best and the tissue damage was minimized when the mass fraction was 0.7% and the temperature was 3℃. Circulating cold air parameters: The temperature was set to 4℃, 5℃, and 6℃, and the wind speed was set to 2m / s, 2.5m / s, and 3m / s respectively. The results showed that the cooling efficiency was the highest when the temperature was 5℃ and the wind speed was 2.5m / s, and the crisp and tender texture of the bamboo fungus was best maintained. UV irradiation parameters: Irradiation time was set to 20 min and 25 min, and dose was set to 1.0 kJ / m² and 1.2 kJ / m², respectively. The results showed that when the irradiation time was 20-25 min and the dose was 1.0-1.2 kJ / m², the bactericidal effect was significant and there was no tissue damage. Modified atmosphere gas ratios: oxygen 3% + carbon dioxide 5%, oxygen 5% + carbon dioxide 8%, and oxygen 5% + carbon dioxide 15% were set respectively. The results showed that when oxygen 5% + carbon dioxide 8% (nitrogen 87%), the respiratory metabolism inhibition effect of bamboo fungus was the best and the quality was best maintained.

[0041] The above description is merely a preferred embodiment of the present invention and does not limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any changes, modifications, substitutions, integrations, and parameter alterations to these embodiments within the spirit and principles of the present invention, achieved through conventional substitutions or by achieving the same function without departing from the principles and spirit of the present invention, fall within the scope of protection of the present invention.

Claims

1. A method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging, characterized in that... Includes the following steps: Step S1, Harvesting and Pretreatment: Harvest the fruiting bodies of red-capped bamboo fungus from the oval stage to the half-expanded stage of the veil. Within 2 hours after harvesting, clean and remove the residual veil and impurities. Gently rinse the cleaned red-capped bamboo fungus in a sterile salt solution, then remove it and place it in a high-intensity circulating cold air to quickly dry the surface moisture, so that the temperature of the core of the fungus drops to 8-10℃ within 30 minutes. Step S2, UV irradiation treatment: The surface-dried pre-cooled red bamboo fungus is laid in a single layer on a clean bench and irradiated through a closed channel equipped with a short-wave ultraviolet irradiation device. The irradiation process is carried out at room temperature. Step S3, Modified Atmosphere Packaging: Immediately after UV irradiation, the red-topped bamboo fungus is placed into a preservation box, and a mixed gas is injected into the preservation box to form a modified atmosphere. The mixed gas has an oxygen concentration of 3%-5%, a carbon dioxide concentration of 5%-15%, and the remaining gas is nitrogen. Step S4, Storage: Store the modified atmosphere packaged red bamboo fungus in an environment of 0-4℃.

2. The method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging according to claim 1, characterized in that... In step S1, the red-topped bamboo fungus is harvested during its oval stage, when the veil is not broken.

3. The method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging according to claim 2, characterized in that... In step S1, the mass fraction of the sterile saline solution is 0.5-1.0%, and the temperature is 1-7℃.

4. The method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging according to claim 3, characterized in that... In step S1, the rinsing time is 1 to 2 minutes.

5. The method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging according to claim 4, characterized in that... In step S1, the temperature of the high-intensity circulating cold air is 4~6℃ and the wind speed is 2~3m / s.

6. The method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging according to claim 5, characterized in that... In step S1, the sterile saline solution has a mass fraction of 0.7% and a temperature of 3°C, while the high-intensity circulating cold air has a temperature of 5°C and a wind speed of 2.5 m / s.

7. The method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging according to claim 1, characterized in that... In step S2, the cumulative effective irradiation time is 20 minutes and the ultraviolet irradiation dose is 0.8~1.5kJ / m²; or the cumulative effective irradiation time is 25~30 minutes.

8. The method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging according to claim 7, characterized in that... In step S2, the main wavelength of the short-wave ultraviolet light is 254nm.

9. The method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging according to claim 1, characterized in that... In step S3, the mixed gas consists of 5% oxygen, 8% carbon dioxide, and 87% nitrogen.

10. The method for preserving *Dictyophora indicum* using ultraviolet light combined with modified atmosphere packaging according to claim 9, characterized in that... In step S3, the controlled atmosphere environment maintains a stable gas concentration through spontaneous controlled atmosphere technology.

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