A new postharvest storage preservative composition for plums and a method for preserving plums

Abstract

The application discloses a kind of new plum postharvest storage fresh-keeping composition and its fresh-keeping method.The composition provided by the application comprises 1-MCP, SNP, MeJA and Ag / ZSM-5, and the four components can realize ethylene signal blocking, stress resistance defense activation, ethylene adsorption removal and bacteriostatic preservation simultaneously in synergistic effect.The application can effectively inhibit ethylene release of new plum fruits, reduce respiration rate, delay fruit softening, maintain soluble solids and titratable acid content, keep good color of pericarp, significantly prolong the postharvest storage period of new plum, and is simple, safe and efficient in operation, suitable for commercialization and application.

Description

Technical Field

[0001] This invention relates to a post-harvest storage and preservation composition for plums and its preservation method, belonging to the field of post-harvest storage and preservation technology. Background Technology

[0002] Xinmei ( Prunus domestica Prunus (Prunus), also known as Japanese plum, is an important fresh fruit belonging to the genus Prunus in the Rosaceae family. Kashgar region of Xinjiang Uygur Autonomous Region, due to its unique light and heat conditions and diurnal temperature variation, has become a core production area for fresh plums in my country. The fresh plums produced there are brightly colored, richly flavored, and highly nutritious, making them very popular with consumers. However, fresh plums are typical climacteric fruits, exhibiting vigorous postharvest respiration and metabolism, resulting in a large release of ethylene. Combined with their thin skin, soft flesh, and high water content, they are highly susceptible to softening, dehydration, flavor deterioration, and rotting during postharvest storage and transportation, severely limiting their shelf life and commercial value. Therefore, developing efficient and safe postharvest storage and preservation technologies for fresh plums is of great significance for reducing postharvest losses and extending the market supply period.

[0003] Currently, various treatment technologies have been reported in the field of postharvest preservation of fruits and vegetables. Ethylene receptor inhibitors can irreversibly bind to ethylene receptors, blocking ethylene signal transduction and thus effectively delaying the ripening and senescence process of climacteric fruits. They have been widely used in the storage and preservation of various fruits and vegetables. However, the preservation effect of a single ethylene inhibitor treatment on some fruits is limited, and it is difficult to fully meet the multiple needs of postharvest physiological and metabolic regulation of fruits.

[0004] To enhance preservation effects, researchers have explored combining ethylene inhibitors with other preservatives. For example, ethylene scavengers can oxidize and absorb ethylene gas in the packaging environment; preservatives release antibacterial gases to protect fruits from spoilage; nitric oxide donors have shown potential in regulating fruit stress resistance and delaying senescence; and plant signaling molecules can induce the expression of defense-related genes in fruits, enhancing disease resistance. Furthermore, molecular sieve materials with ethylene adsorption and broad-spectrum antibacterial functions have also been explored for use in fruit and vegetable preservation packaging in recent years.

[0005] Nevertheless, there are no reports in the existing technology of systematically combining ethylene receptor inhibitors with the aforementioned preservatives of various functional types for long-term storage of fresh plums. Existing single or simple binary treatments cannot simultaneously address the multi-dimensional quality deterioration problems such as ethylene ripening, pathogenic microbial growth, and fruit senescence. During long-term storage, fresh plums still exhibit quality problems such as rapid decline in firmness, significant consumption of soluble solids and titratable acids, and deterioration in fruit color, resulting in a shelf life far from meeting the demands of commercial storage and transportation. Therefore, there is a need in this field to develop a composite preservation solution that can comprehensively regulate the postharvest physiological metabolism of fresh plums and also possess antibacterial functions. Summary of the Invention

[0006] This invention addresses the shortcomings of existing post-harvest storage and preservation technologies for fresh plums by providing a post-harvest storage and preservation composition and method for fresh plums. By scientifically combining ethylene receptor inhibitors, nitric oxide donors, plant signaling molecules, and functional molecular sieve materials, it achieves multi-target synergistic regulation of post-harvest physiological metabolism in fresh plums, significantly extending the storage period and maintaining fruit quality.

[0007] The 'new plum' mentioned in this invention refers to the European plum mainly cultivated in Kashgar region of Xinjiang Uygur Autonomous Region ( Prunus domestica L.), a fresh food variety.

[0008] The composition for postharvest storage and preservation of new plums provided by the present invention comprises 1-methylcyclopropene (1-MCP), sodium nitroprusside (SNP), methyl jasmonate (MeJA) and silver-loaded ZSM-5 molecular sieve (Ag / ZSM-5). The silver loading in the silver-loaded ZSM-5 molecular sieve is 3-5 wt%, and the pore size is 0.5-1.5 nm, which is close to the size of an ethylene molecule (0.44 nm).

[0009] In the composition of the present invention, the mass ratio of the 1-methylcyclopropene, the sodium nitroprusside, the methyl jasmonate and the silver-loaded ZSM-5 molecular sieve is (0.5-2):(0.05-0.5):(0.01-0.1):(1-5). Preferably, the mass ratio of the 1-methylcyclopropene, the sodium nitroprusside, the methyl jasmonate, and the silver-loaded ZSM-5 molecular sieve is 1:0.2:0.02:2.

[0010] Based on the aforementioned composition, the present invention further provides a method for post-harvest storage and preservation of fresh plums, comprising the following steps: The fresh plum fruit and an effective amount of the composition of the present invention are placed together in a sealed packaging container for storage.

[0011] In this composition, the 1-methylcyclopropene, sodium nitroprusside, methyl jasmonate, and silver-loaded ZSM-5 molecular sieve are each individually packaged and placed in different positions within the sealed packaging container.

[0012] Preferably, the 1-methylcyclopropene is placed in the upper and / or lower layer of the new plum fruit in the form of a package; the sodium nitroprusside is placed in the lower layer of the new plum fruit in the form of a package; the methyl jasmonic acid is loaded on a preservation card and placed in the upper layer of the new plum fruit; and the silver-loaded ZSM-5 molecular sieve is placed in the upper layer of the new plum fruit in the form of a package.

[0013] Preferably, the new plum fruits are pre-cooled within 6 hours after harvesting, and the pre-cooling method is differential pressure pre-cooling, with a pre-cooling time of 4-8 hours.

[0014] Preferably, the storage temperature is -1 to 2°C; the relative humidity is 75% to 95%.

[0015] Preferably, the sealed packaging container is a cardboard box lined with a biodegradable preservation bag, the cardboard box is provided with divider cardboard and / or nine-grid cardboard, and the preservation bag is sealed after the composition is placed inside.

[0016] The "preservation" involved in this invention refers to inhibiting the release of ethylene from fresh plum fruits, reducing the respiration rate, delaying the decrease in firmness, maintaining the soluble solids and titratable acid content, and / or maintaining the color of the fruit.

[0017] This invention, through the synergistic effect of four components, achieves multi-dimensional delay in the post-harvest senescence process of plums. Specifically, after 120 days of storage, the fruit firmness is more than 26% higher than the control group, and the soluble solids and titratable acid contents are more than 14% and 31% higher, respectively, indicating that fruit softening, sugar consumption, and organic acid degradation are effectively delayed. The peak ethylene release is more than 47% lower than the control group, and the peak respiration is more than 43% lower, indicating that the initiation of fruit ripening is significantly inhibited. At the same time, the peel color is well maintained, with brightness (L value) and yellowness (b value) significantly higher than the control group, and the increase in redness (a value) significantly lower than the control group, indicating that the appearance quality of the fruit is significantly better than that of untreated fruit. In addition, the antibacterial function of Ag / ZSM-5, combined with packaging measures such as preservation bags and absorbent paper, effectively inhibits the growth of microorganisms and the accumulation of condensation during storage, reducing spoilage losses.

[0018] This invention extends the shelf life of fresh plums, which can only be stored for about 2-3 months, to more than 4 months through a synergistic mechanism of "signal blocking - stress induction - gas adsorption - microenvironment improvement". The plums also maintain good product quality when they are shipped out of the warehouse, which significantly extends the shelf life and provides technical support for long-distance transportation and off-peak sales.

[0019] The present invention has the following beneficial technical effects: (1) This invention combines ethylene receptor inhibitors with nitric oxide donors, jasmonic acid signaling molecules and silver-loaded molecular sieves. By utilizing the different target sites and complementary mechanisms among the four, it achieves multi-dimensional synergistic regulation of fruit respiratory metabolism, ethylene biosynthesis, antioxidant defense system and packaging microenvironment, resulting in a significant synergistic effect that cannot be achieved by a single component or binary combination.

[0020] (2) The present invention can effectively inhibit the release of ethylene from new plum fruits, reduce the respiration rate, delay the decrease in fruit firmness, maintain a high content of soluble solids and titratable acid, and maintain the good color of the peel, thereby significantly delaying the ripening and senescence process of the fruit and extending the storage and preservation period.

[0021] (3) The new plums treated with the present invention, after being stored at 0±0.5℃ for 120 days, have a fruit firmness that is more than 26% higher than the control group, and the soluble solids and titratable acid content are more than 14% and 31% higher than the control group, respectively. The peak ethylene release is more than 47% lower than the control group. The quality maintenance effect is significantly better than the existing single or binary treatment schemes.

[0022] (4) The preservative components used in this invention are all food contact permitted materials, which are safe to use. Each component is used in an independent package, and the dosage can be flexibly adjusted according to actual needs. The operation is simple and suitable for large-scale commercial application. Attached Figure Description

[0023] Figure 1 The values ​​of L(A), a(B), and b(C) of Xinmei under different treatment methods are the changes.

[0024] Figure 2 This refers to the changes in the hardness of new plums under different treatment methods.

[0025] Figure 3 This refers to the changes in soluble solids in fresh plums under different treatment methods.

[0026] Figure 4 This refers to the change in titratable acidity of fresh plums under different treatment methods.

[0027] Figure 5 This refers to the changes in the respiratory rate of new plums under different treatment methods.

[0028] Figure 6 This represents the change in ethylene release from new plants under different treatment methods.

[0029] Figure 7 It refers to the temperature and humidity changes in the cold storage.

[0030] Figure 8 It refers to the temperature and humidity changes in different cardboard boxes. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the invention. Other embodiments obtained by those skilled in the art through adjustments to relevant operating steps, parameters, or reagents based on the teachings of the present invention all fall within the protection scope of the present invention.

[0032] The Ag / ZSM-5 used in the following examples has an Ag loading of 3-5 wt% and a pore size of 0.5-1.5 nm, and was purchased from Ningbo Aiboris Environmental Protection Technology Co., Ltd.

[0033] Example 1: Post-harvest storage and preservation method for fresh plums (1) Fruit harvesting and selection In mid-August 2025 (August 19th), plums were harvested at the Xinmei Orchard in Kazankule Village, Shaputule Town, Jiashi County, Kashgar Prefecture, Xinjiang Uygur Autonomous Region. Newly harvested plums that had reached physiological maturity, had intact bloom, and green stems were selected. Workers wore gloves for damage-free harvesting. After harvesting, the plums were directly placed under the trees into double-layered cardboard boxes lined with biodegradable plastic bags. The boxes measured 300mm × 300mm × 215mm. One sheet of absorbent paper was placed on the top and bottom of each box, with each box containing 2kg of plums. The plums were transported to a cold storage facility within 6 hours of harvesting.

[0034] (2) Pre-cooling treatment The fresh plums transported to the cold storage were pre-cooled by pressure differential for 6 hours to bring the core temperature of the fruit down to near the storage temperature.

[0035] (3) Preparation and placement of preservatives After pre-cooling, place the preservative into the biodegradable food storage bag inside the cardboard box as follows: First, place a biodegradable food storage bag (600mm×800mm×0.03mm, narrow side opening) inside the cardboard box. Place absorbent paper at the bottom, then place a nine-grid cardboard box on the bottom. Place the fruit one by one into each grid cell of the nine-grid cardboard box, ensuring an even distribution of fresh plums in each cell. After placing the cardboard boxes, place the top nine-grid cardboard box on top, and continue placing the fruit one by one into each cell of the top nine-grid cardboard box.

[0036] The specific placement method for the preservative is as follows: One packet of 1-MCP (0.5g / packet) and one packet of SNP (200mg / packet) are placed on the bottom layer of absorbent paper; one packet of 1-MCP (0.5g / packet) and one packet of Ag / ZSM-5 (2g / packet) are placed under the top layer of absorbent paper; a preservation card with 20μL of MeJA is placed on the top layer of absorbent paper. That is, each box contains 2 packets of 1-MCP (total 1.0g), 1 packet of SNP (200mg), 1 packet of Ag / ZSM-5 (2g), and 20μL of MeJA (loaded on the preservation card).

[0037] As a control, the control group (CK) did not put any preservatives in the cardboard box, but only put biodegradable preservation bags inside, with absorbent paper at the bottom, then put the lower nine-grid cardboard and put the fruit in, then put the next layer of cardboard, then the upper nine-grid cardboard and put the fruit in, then put absorbent paper on top of the fruit, and finally seal the cardboard box after tying the preservation bag.

[0038] The placement of preservatives in other treatment groups can be adjusted according to the following scheme: 1-MCP+Ag / ZSM-5 group: 2 packs of 1-MCP are placed on the lower absorbent paper and the upper absorbent paper respectively, and 1 pack of Ag / ZSM-5 is placed under the upper absorbent paper.

[0039] 1-MCP+SNP+Ag / ZSM-5 group: 2 packets of 1-MCP are placed on the lower absorbent paper and the upper absorbent paper respectively, 1 packet of Ag / ZSM-5 is placed under the upper absorbent paper, and 1 packet of SNP (200mg / packet) is placed on the lower absorbent paper.

[0040] (4) Packaging sealing and storage After the preservative is applied, the biodegradable preservation bags are sealed, and the cardboard boxes are sealed. All samples are stored in the cold storage of Yuejia Xinmei Industrial Park at a temperature of 0±0.5℃ and a relative humidity of 80-90%. The storage period is 4 months (120 days).

[0041] Example 2: Methods for monitoring quality indicators during storage (1) Color measurement The color of the fruit peel was determined using an LS175 colorimeter. Fifteen fruits were randomly selected from each group, and measurements were taken at three different locations in the equatorial region of each fruit. Each location was measured three times, and the color difference was recorded. Value (brightness), a Value (redness / greenness) and b Value (yellow and blue) (degree). L A higher value indicates a shinier peel. The larger the positive value, the redder the color. A larger positive value indicates a more yellow color.

[0042] (2) Hardness measurement The firmness was measured using a GY-4 digital fruit firmness tester with a probe diameter of 2mm. Three equidistant points were selected in the equatorial region of each new plum fruit. After peeling, the firmness was measured. Fifteen fruits were randomly selected from each treatment group, and the average value was taken.

[0043] (3) Determination of soluble solids and titratable acid content Fifteen fruits were randomly selected from each group, pitted, homogenized, filtered, and 3 ml of the filtrate was collected for sugar and acid content determination using a PAL-BX|ACID F5 integrated sugar and acid analyzer. Each fruit was measured three times, and the soluble solids (TSS) and titratable acid (TA) contents were recorded.

[0044] (4) Measurement of respiration rate and ethylene release rate The static method was used for determination. Fifteen fruits were placed in a 1.5L respiration chamber and left to stand at room temperature for 2 hours. The respiration rate (CO2 release) and ethylene release rate were then measured using an F-950 portable gas analyzer.

[0045] (5) Temperature and humidity monitoring Temperature and relative humidity changes in the cold storage environment and inside cartons of different processing groups were monitored using temperature and humidity recorders, with data recorded every 30 days.

[0046] Example 3: Comparison Test of Preservation Effect Following the method described in Example 1, a control group (CK) and five treatment groups were set up for comparative experiments under the same storage conditions. The preservative combinations for each treatment group are as follows: CK: No preservatives added; Treatment group 1: 1-MCP + Ag / ZSM-5; Treatment group 2: 1-MCP+SNP+Ag / ZSM-5; Treatment group 3: 1-MCP+SNP+MeJA+Ag / ZSM-5.

[0047] In each treatment group, the dosage of 1-MCP was 2 packets (total 1.0 g / box), and the dosage of other reagents was the same as in Example 1. All samples were stored under the same storage conditions (0±0.5℃, RH 80-90%) for 120 days.

[0048] 1. Color The changes in color indicators (L value, a value, b value) during the post-harvest storage of fresh plums are as follows: Figure 1 As shown in the figure, the L value represents brightness; the higher the L value, the brighter the fruit peel color. With prolonged storage, the L values ​​of all groups generally showed a decreasing trend, but the decrease was less pronounced in the treatment groups than in the control group. After 120 days of storage, the L value of the control group decreased to 42.09, while the L value of the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group was 47.58, significantly higher than the control group, indicating that this treatment effectively maintained the brightness of the new plum peel.

[0049] The a-value represents the redness / greenness, with a larger positive value indicating a redder color. Throughout the storage period, the a-values ​​of all groups showed an increasing trend, with the control group showing the largest increase, rising from an initial 10.48 to 14.49 at 120 days. The 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group showed the slowest increase in a-value, reaching 12.31 at 120 days, significantly lower than the control group, indicating that this treatment can effectively inhibit the fruit's color from turning red and delay the ripening process.

[0050] The b-value represents the yellowness or blueness of the fruit; a larger positive value indicates a more yellow color, and it is positively correlated with fruit maturity. The b-values ​​of all groups decreased with prolonged storage time, with the control group showing the most significant decrease, dropping from an initial 12.94 to 2.77 at 120 days. However, the b-value of the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group remained at a higher level, reaching 6.28 at 120 days, significantly higher than the control group, indicating that this treatment effectively delayed the decrease in b-value and maintained fruit color. In summary, the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment was the most effective in maintaining the color of new plums, effectively delaying color change and preserving good appearance quality.

[0051] 2. Hardness The change in hardness of fresh plums over time during post-harvest storage is as follows: Figure 2 As storage time increased, the firmness of all samples showed an overall decreasing trend. The firmness of all treatment groups was higher than that of the control group (CK) in the later stages of storage. Among them, the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment was more effective in maintaining fruit firmness during storage, with its value generally higher than other treatment groups. After 30 days of storage, the firmness of this treatment group was 9.83, significantly higher than the control group's 8.78. After 90 days of storage, the firmness of the control group had decreased to 5.83, while the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group maintained 7.66, 31.4% higher than the control group. At the end of the experiment (120 days), the firmness of the samples in this treatment group was 6.27, 26.2% higher than the CK group's 4.97. Therefore, the 1-MCP+SNP+MeJA+Ag / ZSM-5 combined treatment can effectively delay the decline in fruit firmness and reduce fruit ripening and decay.

[0052] 3. Soluble solids The change in soluble solids content over time during the post-harvest storage of fresh plums is as follows: Figure 3 As shown, the TSS content of each group of samples showed a fluctuating downward trend with the extension of storage time. Throughout the storage period, the TSS content of all treatment groups was higher than that of the CK group, indicating that each treatment could reduce postharvest physiological activity of new plums and delay sugar consumption. Among them, the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment was more effective in maintaining TSS content in the later stage of storage. After 90 days of storage, the TSS content of the control group had dropped to 22.80, while the treatment group still maintained 24.50, which was 7.5% higher than the control group. At the end of the experiment (120 days), the TSS content of the control group was 21.63, while the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group was 24.73, which was significantly higher than the control group and close to the initial value (26.52). Other treatment groups, such as 1-MCP+SNP+Ag / ZSM-5, also maintained 23.60 at 120 days, showing a good maintenance effect. Therefore, it can be seen that the 1-MCP+SNP+MeJA+Ag / ZSM-5 compound treatment can effectively delay the decline of TSS content in new plums and slow down the ripening and senescence process of the fruit.

[0053] 4. Titratable acid The change in titratable acid content over time during the post-harvest storage of fresh plums is as follows: Figure 4As storage time increased, the total ta (TA) content generally showed a decreasing trend, mainly due to the continuous consumption of organic acids by the fruit's respiratory metabolism. Throughout the storage period, the TA content of all treatment groups was higher than that of the control group, indicating that each treatment could effectively delay the degradation of organic acids. Among them, the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment had the most significant effect on maintaining TA content in the later stage of storage. After 90 days of storage, the TA of the control group had dropped to 0.69, while the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group still maintained 1.12, which was 62.3% higher than the control group; at the end of the experiment (120 days), the TA of the control group was 0.71, while that of the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group was 0.93, which was significantly higher than the control group. In addition, the TA of the 1-MCP+SNP+Ag / ZSM-5 treatment reached 1.30 at 60 days, which was higher than other treatments at the same time, but it decreased rapidly in the later stage. Therefore, it can be seen that the 1-MCP+SNP+MeJA+Ag / ZSM-5 compound treatment can effectively delay the decline of TA content in new plums and maintain the fruit's good flavor quality.

[0054] 5. Respiratory rate The change in respiration rate over time during the post-harvest storage of fresh plums is as follows: Figure 5 As shown in the figure, all treatment groups showed a respiratory peak at day 60. The peak value of the control group reached 3.22, while the peak value of the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group was only 1.81, which was 43.8% lower than that of the control group. After 60 days, the respiratory rate of each group showed a decreasing trend. Throughout the storage period, the respiratory rate of the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group remained at a low level, especially in the later stage of storage (day 120), when the respiratory rate of this group dropped to 0.74, which was significantly lower than that of the control group (0.92). The 1-MCP+Ag / ZSM-5 group also showed a certain inhibitory effect, but the effect of the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment was the most significant, indicating that this combined treatment can effectively reduce the postharvest respiratory intensity of fresh plums and delay their physiological metabolic activities.

[0055] 6. Ethylene release rate The change in ethylene release over time during the post-harvest storage of plums is as follows: Figure 6As shown in the figure, the ethylene release rate of the control group was generally higher than that of the treatment group throughout the storage period. The ethylene release of all samples peaked at day 60, with the control group showing the highest peak at 12.67, while the peak of the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group was only 6.7, a decrease of 47.1% compared to the control group. In the early storage period (day 30), the ethylene release of the control group reached 2.04, while the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group was only 0.67, demonstrating a significant inhibitory effect. In the later storage period (day 120), although the ethylene release of each treatment group rebounded somewhat, it remained at a low level overall. The ethylene release of the 1-MCP+SNP+MeJA+Ag / ZSM-5 treatment group was consistently lower than that of other treatment groups, indicating that this combined treatment effectively inhibited ethylene release and delayed the ripening and senescence of the plums.

[0056] Example 4: Temperature and humidity stability verification of the packaging system The cold storage is set to 0℃. For example... Figure 7 As shown, the temperature in the actual cold storage gradually decreased and eventually stabilized at around 0.5℃. The humidity gradually increased and stabilized at around 90℃. This indicates that the cold storage has a stable temperature and humidity control capability. The small fluctuations in temperature and humidity are beneficial for fruit storage.

[0057] The temperature and humidity changes in the chamber were monitored using three groups: CK group, 1-MCP+Ag / ZSM-5 group, and 1-MCP+SNP+JA+Ag / ZSM-5 group. Figure 8 As shown, the temperature changes in different treatment groups tended to be consistent, gradually decreasing and eventually stabilizing at 0.5℃. Meanwhile, the humidity in all groups gradually increased, and although the final humidity values ​​differed, the humidity in each group remained stable. This indicates that the strategy of using cardboard boxes + biodegradable preservation bags can effectively mitigate temperature and humidity fluctuations within the cardboard boxes, providing a stable storage environment for the fruit.

[0058] The experimental results of this invention show that, under cold storage conditions (0 ± 0.5 ℃, 80%–90% RH), plums treated with 1-MCP alone and those treated with 1-MCP in combination with Ag / ZSM-5, SNP, and MeJA all achieved better storage and preservation effects than the control group. Among these, the combined treatments showed a better synergistic effect than single treatments, and the overall effect was superior to single treatments. Considering all indicators, the plum samples treated with 1-MCP+SNP+MeJA+Ag / ZSM-5 showed the best storage and preservation effect, mainly manifested in effectively inhibiting ethylene release (peak value reduced by 47.1% compared to the control group), reducing fruit respiration intensity, delaying the decline in firmness (26.2% higher than the control group after 120 days of storage), maintaining higher soluble solids and titratable acid content (TSS and TA were 14.3% and 31.6% higher than the control group, respectively), and better preserving fruit color. Compared to the control group, the 1-MCP+SNP+MeJA+Ag / ZSM-5 compound treatment can significantly extend the post-harvest storage and preservation period of new plums.

Claims

1. A composition for postharvest storage and preservation of fresh plums, comprising 1-methylcyclopropene, sodium nitroprusside, methyl jasmonate and silver-loaded ZSM-5 molecular sieve.

2. The composition according to claim 1, characterized in that: The mass ratio of the 1-methylcyclopropene, the sodium nitroprusside, the methyl jasmonate and the silver-loaded ZSM-5 molecular sieve is (0.5-2):(0.05-0.5):(0.01-0.1):(1-5).

3. A method for storing and preserving fresh plums after harvest, comprising the following steps: The fresh plum fruit is placed together with an effective amount of the composition according to claim 1 or 2 in a sealed packaging container for storage.

4. The method according to claim 3, characterized in that: The 1-methylcyclopropene, sodium nitroprusside, methyl jasmonate, and silver-loaded ZSM-5 molecular sieve in the composition are each individually packaged and placed in different positions within the sealed packaging container.

5. The method according to claim 4, characterized in that: The 1-methylcyclopropene is placed in the upper and / or lower layer of the new plum fruit in the form of a package; the sodium nitroprusside is placed in the lower layer of the new plum fruit in the form of a package; the methyl jasmonic acid is loaded on a preservation card and placed in the upper layer of the new plum fruit; the silver-loaded ZSM-5 molecular sieve is placed in the upper layer of the new plum fruit in the form of a package.

6. The method according to any one of claims 3-5, characterized in that: The newly harvested plums are pre-cooled within 6 hours after harvesting. The pre-cooling method is differential pressure pre-cooling, and the pre-cooling time is 4-8 hours.

7. The method according to any one of claims 3-6, characterized in that: The storage temperature is -1 to 2℃; the relative humidity is 75% to 95%.

8. The method according to any one of claims 3-7, characterized in that: The sealed packaging container is a cardboard box lined with a biodegradable preservation bag. The cardboard box contains divider cardboard and / or a nine-grid cardboard box. The preservation bag is sealed after the composition is placed inside.

9. The use of the composition according to claim 1 or 2 in the preparation of post-harvest storage and preservation products for fresh plums.

10. The application according to claim 9, characterized in that: The storage and preservation products are used to inhibit the release of ethylene from fresh plum fruits, reduce the respiration rate, delay the decrease in firmness, maintain the soluble solids and titratable acid content, and / or maintain the color of the fruit.

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