A plant source preservative of gomphocarpus physocarpus and its preparation method and application

Abstract

This invention discloses a plant-derived preservative for Akebia quinata, its preparation method, and its application, belonging to the field of fruit and vegetable preservation technology. The preservative uses young Akebia quinata fruit as the main raw material, combined with Sophora flavescens, Phellodendron chinense, and Zanthoxylum bungeanum, and is prepared through primary yeast fermentation and secondary fermentation with Lactobacillus plantarum and Bacillus amyloliquefaciens. The preservative significantly reduces polyphenol oxidase (PPO) activity, effectively inhibiting enzymatic browning in Akebia quinata; after 14 days of storage at room temperature, the rot rate decreases to 64%-66%, with effects comparable to imazalil; it delays fruit cracking, reduces the cracking rate, and decreases the length and width of the ventral suture; it also has a significant inhibitory effect on Escherichia coli and Staphylococcus aureus. The product of this invention is purely plant-derived, with no chemical residues, and possesses four functions: inhibiting browning, preventing rot, preventing fruit cracking, and broad-spectrum antibacterial activity. The process is stable, and the application is simple, making it suitable for post-harvest green preservation of Akebia quinata and showing good industrialization prospects.

Description

Technical Field

[0001] This invention belongs to the field of fruit and vegetable preservation technology, specifically relating to a plant-derived preservative for Akebia quinata, its preparation method and application, a preservative using young Akebia quinata fruit as the main raw material and compounded with plant-derived antibacterial components, its preparation method and its application in the preservation of Akebia quinata. Background Technology

[0002] The akebia quinata (scientific name: Akebia trifoliata, Akebia quinata) is an important wild berry in my country, used both as food and medicine. It is widely distributed in Central, Southwest, and South China. Its flesh is sweet, juicy, and has a unique flavor, rich in polyphenols, flavonoids, amino acids, minerals, and various bioactive components. It possesses both nutritional value and medicinal and health-promoting functions, and in recent years has become a high-value specialty fruit with continuously rising market demand. However, the akebia quinata is a typical climacteric fruit, exhibiting vigorous post-harvest physiological metabolism, a thin and brittle peel, poor toughness, and high water content. During storage, transportation, and sales at room temperature, it is highly susceptible to three major quality deterioration problems: polyphenol oxidase (PPO)-mediated enzymatic browning, pathogen infection leading to rot and mold, and post-harvest fruit cracking caused by physiological metabolic imbalance. The combined effect of these problems results in a shelf life of only 3-5 days at room temperature, low marketable fruit rate, high loss rate, and short storage period, severely limiting its large-scale planting, industrial processing, and long-distance distribution. This has become a key technological bottleneck restricting the high-quality development of the akebia quinata industry. In large-scale cultivation, to ensure the market quality and yield of the fruit, thinning is necessary during the growth period of August melon to remove excessive young fruits and retain healthy ones. This results in a large number of immature young fruits. These young fruits are usually discarded directly, resulting in extremely low utilization rates. This not only wastes resources but also puts pressure on field waste disposal, and no high-value utilization pathways have yet been developed.

[0003] Currently, post-harvest preservation of fruits and vegetables still relies heavily on chemical preservatives, such as broad-spectrum fungicides like imazalil, thiophanate-methyl, and methyl thiophanate, which are widely used in production to inhibit pathogens and reduce spoilage rates. However, the long-term and excessive use of chemical preservatives can easily lead to problems such as excessive pesticide residues, environmental pollution, increased pathogen resistance, and rising food safety risks. This contradicts the development trends of green food, organic agriculture, and healthy consumption upgrades, and fails to meet the quality requirements of high-end markets and export trade. As consumers increasingly demand safe, natural, and additive-free preservation products, developing plant-based and bio-based green preservation technologies has become an important research direction in the field of fruit and vegetable preservation.

[0004] In recent years, scholars both domestically and internationally have conducted extensive research on preservation using plant extracts and natural antibacterial substances. However, existing technologies mostly focus on the extraction of single plant components, which suffer from drawbacks such as limited functionality, narrow antibacterial spectrum, difficulty in synergistic effects between inhibiting browning and preventing fruit cracking, and poor stability. These technologies cannot specifically address the multi-factor-related quality deterioration issues of August melons after harvest. Furthermore, there is a lack of research on specialized preservatives targeting the postharvest physiological characteristics, browning mechanisms, cracking patterns, and pathogenic microorganisms of August melons. In particular, there is a lack of integrated green preservation solutions that combine the high-value utilization of thinned and discarded young fruits with bio-fermentation and plant-based compound formulations.

[0005] Furthermore, traditional preservation techniques do not fully utilize the active substances such as polyphenols and organic acids contained in the young fruits of the August melon, resulting in low resource utilization and insufficient functionality. Therefore, turning the large amount of young August melon fruits generated from fruit thinning into a valuable resource by combining them with natural antibacterial plant components such as Sophora flavescens, Phellodendron chinense, and Zanthoxylum bungeanum, and preparing a special preservative through microbial fermentation, can not only improve the resource utilization rate of waste young fruits, but also develop a green preservation product that inhibits PPO enzymatic browning, has broad-spectrum antibacterial properties, delays fruit cracking, and reduces the rate of decay. This has significant theoretical value and broad application prospects for extending the shelf life of August melons, improving product quality, reducing post-harvest losses, and promoting the green and sustainable development of the industry. Summary of the Invention

[0006] The purpose of this invention is to address the problems of easy browning, rotting, and cracking of Akebia quinata after harvest, as well as the waste of a large number of young fruits due to thinning. This invention provides a plant-derived preservative for Akebia quinata, its preparation method, and its application, belonging to the field of green preservation technology for fruits and vegetables.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a plant-derived preservative for Akebia quinata, made from the following raw materials in parts by weight: 800-1200 parts of fresh young Akebia quinata fruit, 80-150 parts of Sophora flavescens, 50-90 parts of Phellodendron chinense, 30-70 parts of Zanthoxylum bungeanum, 200-400 parts of white sugar, 8-18 parts of yeast, 2-5 parts of Lactobacillus plantarum, 1-3 parts of Bacillus amyloliquefaciens, and 2000-4000 parts of water; the preservative is prepared by primary fermentation with yeast and secondary fermentation with a compound bacteria composed of Lactobacillus plantarum and Bacillus amyloliquefaciens.

[0008] The aforementioned akebia plant-derived preservative is preferably made from the following raw materials in parts by weight: 1000 parts of fresh young akebia fruit, 120 parts of sophora flavescens, 70 parts of phellodendron chinense, 50 parts of Sichuan pepper powder, 360 parts of white sugar, 12 parts of yeast, 3 parts of lactobacillus plantarum, 1.5 parts of Bacillus amyloliquefaciens, and 3000 parts of water.

[0009] The preparation method of the August melon plant-derived preservative includes the following steps: A. Raw material pretreatment: Wash and crush the young fruits of the August melon, and mix the powdered Sophora flavescens and Phellodendron chinense with Sichuan pepper. B. Primary fermentation: Mix crushed Akebia quinata, Sophora flavescens, Phellodendron chinense, Sichuan pepper, white sugar, and water, add yeast, seal and ferment at 25-32℃ for 10-20 days to obtain primary fermentation liquid; C. Secondary fermentation: Inoculate the primary fermentation broth with Lactobacillus plantarum and Bacillus amyloliquefaciens, and continue fermentation at 25-30℃ for 30-80 days, with a total fermentation time of 50-90 days; Post-treatment: Filter and centrifuge the fermentation broth, and take the supernatant to obtain the preservative mother liquor.

[0010] The first fermentation in step B takes 14 days, the second fermentation in step C takes 46 days, and the total fermentation time is 60 days.

[0011] The application of the plant-derived preservative for Akebia quinata in postharvest preservation: The plant-derived preservative for Akebia quinata is used to inhibit polyphenol oxidase activity, inhibit enzymatic browning of Akebia quinata, reduce the rate of decay, reduce fruit cracking, and inhibit Escherichia coli or Staphylococcus aureus in postharvest preservation. Compared with the control group, the preservation effect is more than 7 days.

[0012] The application of the plant-derived preservative of Akebia quinata in inhibiting PPO enzymatic browning of Akebia quinata: When the plant-derived preservative of Akebia quinata inhibits the activity of polyphenol oxidase, it inhibits the enzymatic browning of Akebia quinata. The preservative stock solution is diluted to 0.5% to 10% by volume. Among them, the 10% dilution results in the lowest residual PPO enzyme activity and the strongest browning inhibition effect.

[0013] The application of the plant-derived preservative for Akebia quinata in reducing the post-harvest decay rate of Akebia quinata: When the plant-derived preservative for Akebia quinata reduces the post-harvest decay rate of Akebia quinata, the preservative stock solution is diluted to 0.5%-10% by volume and sprayed evenly on the surface of Akebia quinata using a spray bottle. The decay rate after 14 days is significantly lower than that of the control group, and the effect is comparable to that of imazalil.

[0014] The application of the plant-derived preservative for Akebia quinata in reducing the postharvest cracking rate of Akebia quinata involves diluting the preservative stock solution to 2.5%-10% by volume and spraying it onto 80% mature Akebia quinata every other day for 12 consecutive days. This can reduce the cracking rate, shorten the length of the ventral suture, and reduce the width of the ventral suture.

[0015] The application of the plant-derived preservative from August melon in inhibiting Escherichia coli and / or Staphylococcus aureus, using the mother liquor of the preservative fermented for a total of 60 days, showed a significantly better inhibitory effect on Escherichia coli and Staphylococcus aureus than the 30-day and 90-day fermentation groups.

[0016] The plant-derived preservative for August melon is plant-based, contains no chemical bactericide residues, and is suitable for green preservation of August melon after harvest.

[0017] Compared with the prior art, the present invention has the following outstanding features: (1) This invention uses the discarded young fruit of the August melon as the main raw material, turning waste into treasure, significantly improving the utilization rate of by-products, reducing field waste pollution, and having both ecological and economic benefits.

[0018] (2) The plant-derived preservative for Akebia quinata described in this invention exhibits enhanced inhibitory effects with increasing concentration within the range of 0.5% to 10%. A 10% dilution can minimize the residual PPO enzyme activity, resulting in optimal browning inhibition. After a single spray treatment and 14 days of storage at room temperature, the rot rate of Akebia quinata can be reduced to 64% to 66%, significantly lower than the 88% rot rate of the control group, with effects comparable to or even better than 68% of imazalil. Spraying with a 2.5% to 10% dilution every 2 days for 12 consecutive days can delay the onset of fruit cracking from day 1 to day 3, significantly reducing the cracking rate and effectively shortening the length and width of the abdominal suture. In addition, the preservative fermented for 60 days exhibits the strongest inhibitory effect against Escherichia coli and Staphylococcus aureus, with a significantly larger inhibition zone diameter than the 30-day and 90-day fermentation groups, demonstrating stable and reliable preservation and antibacterial effects.

[0019] (3) It is prepared by pure plant raw materials and biological fermentation, without chemical bactericides, safe and biodegradable, meeting the requirements of green food and organic fruit and vegetable preservation. The secondary fermentation process is mild, the parameters are controllable, the operation is simple, the cost is low, and it is suitable for large-scale production and field application, with high promotion value. Attached Figure Description

[0020] Figure 1 Effects of different dilution gradients of Akebia quinata plant-derived preservative on the residual PPO enzyme activity Figure 2 Photos showing the effect of different dilution concentrations of plant-derived preservatives on the degree of rotting in August melons.

[0021] Figure 3 Comparison of data on the rot rate of Akebia quinata with different dilution concentrations of plant-derived preservatives.

[0022] Figure 4 Comparison of the effects of different dilution concentrations of plant-derived preservatives on the degree of cracking in August melons (Akebia quinata).

[0023] Figure 5 Comparison of data on cracking of Akebia quinata fruit at different dilution concentrations of plant-derived preservative.

[0024] Figure 6 The inhibitory effect of the plant-derived preservative from Akebia quinata on Escherichia coli is shown in the image.

[0025] Figure 7 The effect of the plant-derived preservative from Akebia quinata on the inhibition of Staphylococcus aureus is shown in the figure. Specific Implementation

[0026] To make the technical solution of the present invention and its beneficial effects compared with the prior art clearer and more specific, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Example 1

[0027] A plant-derived preservative for Akebia quinata, made from the following raw materials in parts by weight: 1000 parts of fresh young Akebia quinata fruit, 120 parts of Sophora flavescens, 70 parts of Phellodendron chinense, 50 parts of Sichuan pepper powder, 360 parts of white sugar, 12 parts of yeast, 3 parts of Lactobacillus plantarum, 1.5 parts of Bacillus amyloliquefaciens, and 3000 parts of water.

[0028] The preparation method of the August melon plant-derived preservative includes the following steps: A. Raw material pretreatment: Wash and crush the young fruits of the August melon, and mix the powdered Sophora flavescens and Phellodendron chinense with Sichuan pepper. B. Primary fermentation: Mix crushed Akebia quinata, Sophora flavescens, Phellodendron chinense, Sichuan pepper, white sugar, and water, add yeast, seal and ferment at 25-32℃ for 14 days to obtain primary fermentation liquid; C. Secondary fermentation: Inoculate the primary fermentation broth with Lactobacillus plantarum and Bacillus amyloliquefaciens, and continue fermentation at 25-30℃ for 46 days, for a total fermentation time of 60 days. Post-treatment: Filter and centrifuge the fermentation broth, and take the supernatant to obtain the preservative mother liquor.

[0029] The first fermentation in step B takes 14 days, the second fermentation in step C takes 46 days, and the total fermentation time is 60 days.

[0030] The application of the plant-derived preservative for Akebia quinata in postharvest preservation: The plant-derived preservative for Akebia quinata is used to inhibit polyphenol oxidase activity, inhibit enzymatic browning of Akebia quinata, reduce the rate of decay, reduce fruit cracking, and inhibit Escherichia coli or Staphylococcus aureus in postharvest preservation. Compared with the control group, the preservation effect is more than 7 days.

[0031] The application of the plant-derived preservative of Akebia quinata in inhibiting PPO enzymatic browning of Akebia quinata: When the plant-derived preservative of Akebia quinata inhibits the activity of polyphenol oxidase, it inhibits the enzymatic browning of Akebia quinata. The preservative stock solution is diluted to 0.5% to 10% by volume. Among them, the 10% dilution results in the lowest residual PPO enzyme activity and the strongest browning inhibition effect.

[0032] The application of the plant-derived preservative for Akebia quinata in reducing the post-harvest decay rate of Akebia quinata: When the plant-derived preservative for Akebia quinata reduces the post-harvest decay rate of Akebia quinata, the preservative stock solution is diluted to 0.5%-10% by volume and sprayed evenly on the surface of Akebia quinata using a spray bottle. The decay rate after 14 days is significantly lower than that of the control group, and the effect is comparable to that of imazalil.

[0033] The application of the plant-derived preservative for Akebia quinata in reducing the postharvest cracking rate of Akebia quinata involves diluting the preservative stock solution to 2.5%-10% by volume and spraying it onto 80% mature Akebia quinata every other day for 12 consecutive days. This can reduce the cracking rate, shorten the length of the ventral suture, and reduce the width of the ventral suture.

[0034] The application of the plant-derived preservative from August melon in inhibiting Escherichia coli and / or Staphylococcus aureus, using the mother liquor of the preservative fermented for a total of 60 days, showed a significantly better inhibitory effect on Escherichia coli and Staphylococcus aureus than the 30-day and 90-day fermentation groups.

[0035] The plant-derived preservative for August melon is plant-based, contains no chemical bactericide residues, and is suitable for green preservation of August melon after harvest. Example 2

[0036] A plant-derived preservative for Akebia quinata is made from the following raw materials in parts by weight: 800 parts of fresh young Akebia quinata fruit, 150 parts of Sophora flavescens, 50 parts of Phellodendron chinense, 70 parts of Zanthoxylum bungeanum, 200 parts of white sugar, 18 parts of yeast, 2 parts of Lactobacillus plantarum, 3 parts of Bacillus amyloliquefaciens, and 2000 parts of water; the preservative is prepared by primary fermentation with yeast and secondary fermentation with a compound of Lactobacillus plantarum and Bacillus amyloliquefaciens.

[0037] The preparation method of the August melon plant-derived preservative includes the following steps: A. Raw material pretreatment: Wash and crush the young fruits of the August melon, and mix the powdered Sophora flavescens and Phellodendron chinense with Sichuan pepper. B. Primary fermentation: Mix crushed akebia fruit, sophora flavescens, phellodendron bark, Sichuan pepper, white sugar, and water, add yeast, seal and ferment at 25℃ for 20 days to obtain primary fermentation liquid; C. Secondary fermentation: Inoculate the primary fermentation broth with Lactobacillus plantarum and Bacillus amyloliquefaciens, and continue fermentation at 30°C for 30 days, for a total fermentation time of 50 days. Post-treatment: Filter and centrifuge the fermentation broth, and take the supernatant to obtain the preservative mother liquor.

[0038] The first fermentation in step B takes 20 days, the second fermentation in step C takes 30 days, and the total fermentation time is 50 days.

[0039] The application of the plant-derived preservative for Akebia quinata in postharvest preservation: The plant-derived preservative for Akebia quinata is used to inhibit polyphenol oxidase activity, inhibit enzymatic browning of Akebia quinata, reduce the rate of decay, reduce fruit cracking, and inhibit Escherichia coli or Staphylococcus aureus in postharvest preservation. Compared with the control group, the preservation effect is more than 7 days.

[0040] The application of the plant-derived preservative of Akebia quinata in inhibiting PPO enzymatic browning of Akebia quinata: When the plant-derived preservative of Akebia quinata inhibits the activity of polyphenol oxidase, it inhibits the enzymatic browning of Akebia quinata. The preservative stock solution is diluted to 0.5% to 10% by volume. Among them, the 10% dilution results in the lowest residual PPO enzyme activity and the strongest browning inhibition effect.

[0041] The application of the plant-derived preservative for Akebia quinata in reducing the post-harvest decay rate of Akebia quinata: When the plant-derived preservative for Akebia quinata reduces the post-harvest decay rate of Akebia quinata, the preservative stock solution is diluted to 0.5%-10% by volume and sprayed evenly on the surface of Akebia quinata using a spray bottle. The decay rate after 14 days is significantly lower than that of the control group, and the effect is comparable to that of imazalil.

[0042] The application of the plant-derived preservative for Akebia quinata in reducing the postharvest cracking rate of Akebia quinata involves diluting the preservative stock solution to 2.5%-10% by volume and spraying it onto 80% mature Akebia quinata every other day for 12 consecutive days. This can reduce the cracking rate, shorten the length of the ventral suture, and reduce the width of the ventral suture.

[0043] The application of the plant-derived preservative from August melon in inhibiting Escherichia coli and / or Staphylococcus aureus, using the mother liquor of the preservative fermented for a total of 60 days, showed a significantly better inhibitory effect on Escherichia coli and Staphylococcus aureus than the 30-day and 90-day fermentation groups.

[0044] The plant-derived preservative for August melon is plant-based, contains no chemical bactericide residues, and is suitable for green preservation of August melon after harvest. Example 3: Preparation of the optimal preservative formula in actual production

[0045] Weigh out 10 kg of young akebia fruit, 1.2 kg of sophora flavescens, 0.7 kg of phellodendron bark, 0.5 kg of Sichuan pepper, 3.6 kg of white sugar, 120 g of yeast, and 30 kg of water; mix them together and inoculate with yeast, ferment at 28℃ for 14 days; inoculate with 30 g of lactobacillus plantarum and 15 g of Bacillus amyloliquefaciens, and continue fermenting at 28℃ for 46 days, for a total fermentation of 60 days; filter and centrifuge, and the supernatant is the preservative mother liquor. Example 4: Effect of Akebia quinata plant-derived preservative on the residual activity of polyphenol oxidase (PPO) during storage.

[0046] Polyphenol oxidase (PPO) plays a crucial role in fruit spoilage. PPO is an enzyme widely found in plant tissues. When fruit is mechanically damaged or exposed to air, PPO catalyzes the oxidation of phenolic substances to quinones, forming brown polymers and causing browning. A preservative for *Akebia quinata* was diluted to different concentration gradients. 0.1 mL of different concentrations of the preservative was added to an activity assay system containing 1.6 mL of pH 6.3 disodium hydrogen phosphate-citric acid buffer and 0.3 mL of enzyme solution. After reacting at 30°C for 10 min, 1.0 mL of 20 mmol·L⁻¹ catechol was added, mixed thoroughly, and reacted at 30°C for 30 min. The enzyme activity was calculated by measuring the OD value at 420 nm. Changes in enzyme activity before and after inhibitor treatment were expressed as residual enzyme activity.

[0047] The test results are shown in Figure 1 ,Depend on Figure 1 It can be seen that the plant-derived preservative of Akebia quinata can inhibit PPO activity. When the concentration is 0.5-10%, the residual PPO enzyme activity gradually decreases and the inhibitory effect gradually increases with the increase of the concentration of the preservative solution. When the concentration is 10-100%, the residual PPO enzyme activity gradually increases and the inhibitory effect gradually weakens with the increase of the preservative concentration. When the concentration of the preservative is 10%, the residual PPO enzyme activity is the lowest, showing the strongest PPO inhibitory effect. Example 5: Effect of plant-derived preservatives for Akebia quinata on the rot rate of Akebia quinata

[0048] To further investigate the effect of plant-derived preservatives on the rot rate of *Akebia quinata* within 14 days, 300 *Akebia quinata* fruits were divided into 6 groups: a control group, a prochloraz positive control group, and groups treated with 0.5%, 1%, 2%, and 10% of the preservative, with 50 fruits in each group. The preservative was sprayed once, and the rot was observed after 14 days. The rot rates of the *Akebia quinata* fruits in each group after 14 days are as follows: Figure 2 and 3 The decay rate in the blank control group was 88%, the decay rate in the prochloraz positive control group was 68%, and the decay rates in the 0.5%, 1%, 2%, and 10% groups of Akebia quinata preservative were 66%, 64%, 72%, and 64%, respectively. All groups of Akebia quinata preservative showed good decay inhibition rates, and the inhibition effect was basically equivalent to that of the positive control group. Example 6: The effect of plant-derived preservatives for Akebia quinata on cracking in Akebia quinata.

[0049] Eight-tenths-ripe Akebia quinata fruits were selected to investigate the effects of plant-derived preservatives on the cracking rate, ventral suture length ratio, and ventral suture width. Forty Akebia quinata fruits were divided into four groups: a control group, and groups treated with 2.5%, 5%, and 10% preservatives, with ten fruits in each group. The preservative was sprayed once every other day, and the changes in each indicator were observed over 12 days. Results are shown below. Figure 4 and 5 In terms of cracking rate, the preservative groups for August melon were generally lower than the control group. The control group showed cracking on the first day, while the 10% group did not show cracking until the third day. In terms of the ratio of abdominal suture length, the preservative groups for August melon were generally smaller than the control group. In terms of abdominal suture width, after the eighth day, the preservative groups for August melon were all smaller than the control group, especially the 10% group, whose abdominal suture width was much lower than the control group. Example 7: Inhibitory effect of Akebia quinata plant-derived preservative on Escherichia coli and Staphylococcus aureus

[0050] The inhibitory effects of a plant-derived preservative from *Akebia quinata* on *Escherichia coli* and *Staphylococcus aureus* were investigated. Young *Akebia quinata* fruits were fermented according to a specific process, and the antibacterial activity of the preservative was measured after 30, 60, and 90 days of fermentation. The experimental results are shown below. Figure 6 and 7 As shown in the figure, the 30-day, 60-day, and 90-day preservatives for Akebia quinata can all inhibit the growth of Escherichia coli and Staphylococcus aureus, and the 60-day preservative for Akebia quinata has the best antibacterial effect.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments without departing from the technical essence of the present invention shall still fall within the scope of the present invention.

Claims

1. A plant-derived preservative for Akebia quinata, characterized in that, It is made from the following raw materials in parts by weight: 800-1200 parts of fresh young fruit of Akebia quinata, 80-150 parts of Sophora flavescens, 50-90 parts of Phellodendron chinense, 30-70 parts of Zanthoxylum bungeanum, 200-400 parts of white sugar, 8-18 parts of yeast, 2-5 parts of Lactobacillus plantarum, 1-3 parts of Bacillus amyloliquefaciens, and 2000-4000 parts of water; the preservative is prepared by primary fermentation of yeast and secondary fermentation of a compound bacteria composed of Lactobacillus plantarum and Bacillus amyloliquefaciens.

2. The akebia quinata plant-derived preservative according to claim 1, characterized in that, Made from the following ingredients in parts by weight: 1000 parts fresh young fruit of Akebia quinata, 120 parts Sophora flavescens, 70 parts Phellodendron chinense, 50 parts Sichuan pepper powder, 360 parts white sugar, 12 parts yeast, 3 parts Lactobacillus plantarum, 1.5 parts Bacillus amyloliquefaciens, and 3000 parts water.

3. A method for preparing the akebia plant-derived preservative as described in any one of claims 1-2, characterized in that, Includes the following steps: A. Raw material pretreatment: Wash and crush the young fruits of the August melon, and mix the powdered Sophora flavescens and Phellodendron chinense with Sichuan pepper. B. Primary fermentation: Mix crushed Akebia quinata, Sophora flavescens, Phellodendron chinense, Sichuan pepper, white sugar, and water, add yeast, seal and ferment at 25-32℃ for 10-20 days to obtain primary fermentation liquid; C. Secondary fermentation: Inoculate the primary fermentation broth with Lactobacillus plantarum and Bacillus amyloliquefaciens, and continue fermentation at 25-30℃ for 30-80 days, with a total fermentation time of 50-90 days; Post-treatment: Filter and centrifuge the fermentation broth, and take the supernatant to obtain the preservative mother liquor.

4. The preparation method according to claim 3, characterized in that, The first fermentation time in step B is 14 days, the second fermentation time in step C is 46 days, and the total fermentation time is 60 days.

5. The application of the plant-derived preservative for Akebia quinata as described in any one of claims 1-2 in the postharvest preservation of Akebia quinata, characterized in that, The plant-derived preservative for Akebia quinata is used in postharvest preservation to inhibit polyphenol oxidase activity, inhibit enzymatic browning of Akebia quinata, reduce the rate of decay, reduce fruit cracking, and inhibit Escherichia coli or Staphylococcus aureus. Compared with the control group, the preservation effect extends the shelf life to more than 7 days.

6. The application of the plant-derived preservative of Akebia quinata as described in any one of claims 1-2 in inhibiting PPO-induced browning in Akebia quinata, characterized in that, When the plant-derived preservative for Akebia quinata inhibits the activity of polyphenol oxidase, it also inhibits the enzymatic browning of Akebia quinata. The preservative stock solution is diluted to 0.5% to 10% by volume before use; the 10% dilution results in the lowest residual PPO enzyme activity and the strongest browning inhibition effect.

7. The application of the plant-derived preservative for Akebia quinata according to any one of claims 1-2 in reducing the post-harvest decay rate of Akebia quinata, characterized in that, When the plant-derived preservative for Akebia quinata reduced the post-harvest rot rate, the preservative stock solution was diluted to 0.5%-10% by volume and applied evenly to the surface of the Akebia quinata using a spray bottle. After 14 days, the rot rate was significantly lower than that of the control group, and the effect was comparable to that of imazalil.

8. The application of the plant-derived preservative for Akebia quinata according to any one of claims 1-2 in reducing the postharvest fruit cracking rate of Akebia quinata, characterized in that, When the plant-derived preservative for akebia fruit reduces fruit cracking, the preservative stock solution is diluted to 2.5%-10% by volume, and sprayed onto 80% mature akebia fruit every other day for 12 consecutive days. This can reduce the fruit cracking rate, shorten the length of the ventral suture, and reduce the width of the ventral suture.

9. The application of the *Akebia quinata* plant-derived preservative according to any one of claims 1-2 in inhibiting *Escherichia coli* and / or *Staphylococcus aureus*, characterized in that, The preservative mother liquor fermented for a total of 60 days showed significantly better inhibitory effects on Escherichia coli and Staphylococcus aureus than the fermentation groups fermented for 30 days and 90 days.

10. The application according to claim 5, characterized in that, The plant-derived preservative for August melon is plant-based, contains no chemical bactericide residues, and is suitable for green preservation of August melon after harvest.

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