Integrated preservative and fresh-keeping method for pre-harvest and post-harvest gradient pesticide application

Abstract

The application provides an integrated preservative fresh-keeping method of pre-harvest and post-harvest gradient pesticide application, first, pre-harvest spraying treatment is performed on whole fruits before harvesting, and chitosan oligosaccharide in the spraying liquid can form an ultrathin protective layer on the surface of the fruits and directly inhibit spore germination of pathogenic bacteria, so that the disease resistance of the fruits is improved from the physiological level, and the disease incidence base during storage is reduced from the source; then, the fruits are subjected to preservative immersion treatment after harvesting, so that the sterilization and protection of the fruit skin surface are further strengthened, and calcium ions and film-forming components are supplemented; finally, low-temperature air conditioning and 1-methylcyclopropene storage are combined, so that a gradient cooperation preservative fresh-keeping system of pre-harvest disease induction and post-harvest sterilization and protection is formed. After the gradient cooperation of pre-harvest spraying and post-harvest immersion, a synergistic effect is generated, the rot rate at the fruit stalk is significantly reduced, the storage effect is significantly better than that of post-harvest immersion or pre-harvest spraying alone, and the pre-harvest application of low-toxicity green components reduces the load of post-harvest chemical pesticides, which meets the supervision requirements of green production of fruits.

Description

Technical Field

[0001] This invention relates to the field of postharvest preservation technology for fruits, and in particular to an integrated method for pre-harvest and post-harvest tiered application of pesticides for preservation. Background Technology

[0002] The Akizuki pear has a beautiful yellowish-brown peel, milky-white flesh, a small core, and an edible rate of over 95%. Its flesh is crisp, juicy, and sweet, and it retains its flavor and crispness even after long-term storage. As a pear variety that has become increasingly popular with consumers in recent years, the Akizuki pear's planting area and yield have been increasing annually, with strong market demand. Especially during festivals such as the Mid-Autumn Festival and Spring Festival, high-quality Akizuki pears command high commercial value and market premiums. However, after harvesting, Akizuki pears are prone to softening and spoilage at high temperatures, resulting in rapid softening, peel cracking, browning, and a short shelf life. These issues hinder the further development of the Akizuki pear industry and the enhancement of its added value.

[0003] Existing technologies for storing Akizuki pears typically involve placing them in a low-temperature environment. While this extends the shelf life, prolonged storage can cause the pears to lose water, and excessively low temperatures can lead to softening of the flesh and blackening of the peel. Once removed from the storage area, the pears quickly spoil, affecting transportation. Chinese patent application CN117530333A discloses a method for preserving Akizuki pears. This method involves soaking the pears in a preservative solution containing melatonin, citric acid, ferrous sulfate, calcium chloride, and surfactants, followed by storage and preservation using a low-temperature environment, modified atmosphere packaging, and 1-methylcyclopropene. This reduces water loss, minimizes softening of the flesh, spoilage, and blackening of the peel, and extends the shelf life. However, the aforementioned existing technologies only address surface treatment of the fruit after harvest and cannot address latent pathogens that have already invaded the lenticels and crevices of the fruit stalk during the field stage. The surface structure of Akizuki pears is complex, with natural growth crevices at the junction of the stem and shoulder, and numerous folds in the calyx cavity. During normal pressure immersion, pesticide solutions cannot fully reach these hidden areas. Field pathogens such as ring rot and dry rot often lurk in these locations in spore form, rapidly germinating and growing under suitable temperature and humidity conditions during the later stages of storage. Rotting often begins at the stem, becoming a core cause of fruit loss during medium- to long-term storage. Furthermore, post-harvest pesticide application only acts on the fruit surface tissue and cannot induce improved disease resistance in the fruit itself. Once pathogens breach the surface protection, they are difficult to control, and post-harvest immersion treatment is ineffective in killing pathogens already infiltrated beneath the fruit's surface. In addition, pre-harvest field management has a significant impact on fruit storage performance, but current technologies lack a complete technical solution that organically combines pre-harvest disease control with post-harvest preservation treatment.

[0004] Therefore, there is an urgent need in this field to develop a whole-chain anti-corrosion and preservation method for Akizuki pears that can control latent pathogens from the field source, induce the fruit's own disease resistance, and form a synergistic effect with post-harvest preservation treatment, in order to solve the problem that existing post-harvest preservation technologies cannot effectively control the infection of latent pathogens from the field, which leads to an increased rate of decay in the later stages of storage. Summary of the Invention

[0005] The purpose of this invention is to provide an integrated method for pre- and post-harvest tiered application of pesticides for preservation and freshness, in order to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides an integrated method for pre- and post-harvest tiered pesticide application for preservation and freshness, comprising the following steps: (1) Pre-harvest spraying treatment: 7 to 10 days before the harvest of Akizuki pear, spray the whole fruit plant with the spray solution containing melatonin and chitosan oligosaccharide. When spraying, focus on covering the base of the fruit stalk, the calyx folds and the joint of the fruit shoulder. (2) Harvesting and sorting: When harvesting, retain the fruit stem and stalk, and remove mechanically damaged fruit and fruit with pests and diseases; (3) Post-harvest soaking treatment: After harvesting, the Akizuki pears are soaked in a preservative solution for 5 to 10 minutes under light-proof conditions. The preservative solution contains melatonin, citric acid, ferrous sulfate, calcium chloride and surfactant. After taking them out, they are dried. (4) Controlled atmosphere storage: The soaked Akizuki pears in step (3) are placed in a low-temperature environment and stored under artificial controlled atmosphere conditions by filling with 1-methylcyclopropene.

[0007] Preferably, in the pre-harvest spray solution described in step (1), the concentration of melatonin is 50–200 μmol / L, and the mass percentage concentration of chitosan oligosaccharide is 0.05%–0.2%.

[0008] Preferably, the spraying time in step (1) is selected to be in the evening or on a cloudy day, and the spraying amount is sprayed until the fruit surface is evenly moistened and no dripping occurs.

[0009] Preferably, the pre-harvest spraying in step (1) is carried out by using a backpack sprayer or an orchard wind-assisted sprayer for directional spraying.

[0010] Preferably, the preservative solution in step (3) comprises the following concentrations of raw materials: melatonin 0.5-2 mmol / L, citric acid 0.05-0.2 g / L, ferrous sulfate 0.02-0.3 g / L, calcium chloride 0.5-2 g / L, surfactant 0.1-0.5 g / L, and the remainder is water.

[0011] Preferably, the surfactant in step (3) is either laurate or monooleate.

[0012] Preferably, the low temperature environment in step (4) is 4-10°C and the relative humidity is 85%-90%.

[0013] Preferably, the artificial atmosphere in step (4) is 87%–97% nitrogen, 0.2%–8% oxygen, and 1%–5% carbon dioxide.

[0014] Preferably, the concentration of 1-methylcyclopropene in step (4) is 0.5 to 2 μL / L.

[0015] Preferably, the soaking time of the preservative solution in step (3) is 8 to 10 minutes.

[0016] The present invention achieves the following beneficial technical effects compared to the prior art: This invention provides an integrated pre- and post-harvest tiered application method for preservation and anti-corrosion, characterized by excellent preservation effects, simple operation, and suitability for large-scale application. First, the entire fruit plant is sprayed before harvest. The chitosan oligosaccharides in the spray solution form an ultra-thin protective layer on the fruit surface and directly inhibit the germination of pathogenic spores. The fine mist spray penetrates deep into the crevices of the fruit stalk and calyx folds, killing latent spores of pathogens such as ring rot and dry rot. Simultaneously, low-concentration melatonin induces the synthesis of phytoalexins and disease-resistant proteins in the fruit peel cells, enhancing the fruit's own disease resistance from a physiological perspective and reducing the initial disease incidence during storage. Then, after harvest, the fruit is soaked in a preservative to further enhance the sterilization and protection of the peel surface and replenish calcium ions and film-forming components. Finally, combined with low-temperature controlled atmosphere storage and 1-methylcyclopropylene storage, a tiered preservation and anti-corrosion system is formed, integrating pre-harvest disease resistance induction and post-harvest sterilization and protection. The combined effect of pre-harvest spraying and post-harvest immersion resulted in a synergistic effect, significantly reducing the rot rate at the fruit stalk. The total rot rate after 120 days of storage could be reduced to below 0.5%, and the water loss rate could be controlled within 3.5%. The storage effect was significantly better than that of post-harvest immersion or pre-harvest spraying alone. Furthermore, the application of low-toxicity green components before harvest reduced the load of post-harvest chemical agents, meeting the regulatory requirements for green fruit production and adapting to the standardized operating procedures of large-scale orchards. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] The purpose of this invention is to provide an integrated method for pre- and post-harvest tiered application of pesticides for preservation and anti-corrosion, in order to solve the problems existing in the prior art.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to specific embodiments.

[0020] Example 1 An integrated pre- and post-harvest tiered pesticide application method for preserving and preventing spoilage of Akizuki pears includes the following steps: Eight days before harvest, prepare a pre-harvest spray solution containing 100 μmol / L melatonin, 0.1% chitosan oligosaccharide, and the remainder water. Use a backpack sprayer to spray the entire fruit plant, focusing on the base of the fruit stalk, calyx folds, and the joint between the fruit shoulder and stem. Spray until the fruit surface is evenly moistened but not dripping. Spraying should be done in the evening, followed by natural air drying. At harvest, retain the fruit stem and stalk, and remove mechanically damaged or diseased fruit. For insect-damaged fruit, prepare a preservative solution containing 1 mmol / L melatonin, 0.1 g / L citric acid, 0.2 g / L ferrous sulfate, 1 g / L calcium chloride, 0.2 g / L monooleate, and the remainder being water. Soak the harvested Akizuki pears in the preservative solution for 10 minutes under dark conditions, then remove and air dry. Place the soaked Akizuki pears in a low-temperature environment of 5–7℃ and 85%–90% relative humidity, under artificial modified atmosphere conditions of 91% nitrogen, 8% oxygen, and 1% carbon dioxide, and add 1 μL / L of 1-methylcyclopropene for preservation.

[0021] Example 2 An integrated pre- and post-harvest tiered pesticide application method for preserving and preventing spoilage of Akizuki pears includes the following steps: Ten days before harvest, prepare a pre-harvest spray solution containing 150 μmol / L melatonin, 0.15% chitosan oligosaccharide, and water as the remainder. Use an orchard wind-driven sprayer to spray the entire fruit plant, focusing on the base of the fruit stalk, calyx folds, and the joint between the fruit shoulder and stem. Spray until the fruit surface is evenly moistened. Spraying should be done on a cloudy day, followed by natural air drying. At harvest, retain the fruit stem and stalk, and remove mechanically damaged fruit and fruit infected with pests or diseases. To prevent damage to the fruit, prepare a preservative solution containing 1 mmol / L melatonin, 0.1 g / L citric acid, 0.1 g / L ferrous sulfate, 0.8 g / L calcium chloride, 0.3 g / L laurate, and the remainder water. Soak the harvested Akizuki pears in the preservative solution for 8 minutes under dark conditions, then remove and air dry. Place the soaked Akizuki pears in a low-temperature environment of 5–7℃ and 85%–90% relative humidity, under artificial modified atmosphere conditions of 92% nitrogen, 5% oxygen, and 3% carbon dioxide, and add 1 μL / L of 1-methylcyclopropene for preservation.

[0022] Example 3 An integrated pre- and post-harvest tiered pesticide application method for Akizuki pears includes the following steps: Seven days before harvest, prepare a pre-harvest spray solution containing 80 μmol / L melatonin, 0.08% chitosan oligosaccharide, and water as the remainder. Use a backpack sprayer to spray the entire fruit plant, focusing on the base of the fruit stalk, calyx folds, and the joint between the fruit shoulder and the fruit. Spray until the fruit surface is evenly moistened. Spraying should be done in the evening, and the fruit should be allowed to air dry naturally after spraying. At harvest, retain the fruit stem and stalk, and remove mechanically damaged or diseased / insect-infested fruit. Prepare a preservative solution containing 0.5 mmol / L melatonin, 0.2 g / L citric acid, 0.2 g / L ferrous sulfate, 1 g / L calcium chloride, 0.2 g / L monooleate, and the remainder water. Soak the harvested Akizuki pears in the preservative solution for 10 minutes under dark conditions, then remove and air dry. Place the soaked Akizuki pears in a low-temperature environment of 5–7°C and 85%–90% relative humidity, under artificial modified atmosphere conditions of 95% nitrogen, 3% oxygen, and 2% carbon dioxide, and add 1 μL / L of 1-methylcyclopropene for preservation.

[0023] Comparative Example 1 A method for preserving and protecting Akizuki pears includes the following steps: A preservative solution is prepared, containing 1 mmol / L melatonin, 0.1 g / L citric acid, 0.2 g / L ferrous sulfate, 1 g / L calcium chloride, and 0.2 g / L monooleate, with the remainder being water. After harvesting, the Akizuki pears, retaining their stems and pedicels, are immersed in the preservative solution for 10 minutes under dark conditions, then removed and air-dried. The soaked Akizuki pears are then placed in a low-temperature environment of 5–7°C and 85%–90% relative humidity, under artificial modified atmosphere conditions of 91% nitrogen, 8% oxygen, and 1% carbon dioxide, with 1 μL / L of 1-methylcyclopropene added for preservation. The difference between Comparative Example 1 and Example 1 is that pre-harvest spraying is not performed.

[0024] Comparative Example 2 A method for preserving and protecting Akizuki pears includes the following steps: Eight days before harvest, prepare a pre-harvest spray solution containing 100 μmol / L melatonin, 0.1% chitosan oligosaccharide, and the remainder water. Use a backpack sprayer to spray the entire fruit plant, focusing on the base of the fruit stalk, calyx folds, and the joint between the fruit shoulder and stem. Spray until the fruit surface is evenly moistened but not dripping. Spraying should be done in the evening, followed by natural air drying. At harvest, retain the fruit stem and stalk, and remove mechanically damaged or diseased fruit. Place the harvested Akizuki pears in a low-temperature environment of 5–7°C and 85%–90% relative humidity, under controlled atmosphere conditions of 91% nitrogen, 8% oxygen, and 1% carbon dioxide, and add 1 μL / L of 1-methylcyclopropene for preservation. The difference between Comparative Example 2 and Example 1 is that post-harvest immersion treatment is not performed.

[0025] Comparative Example 3 Akizuki pears that have not undergone any treatment were used as comparative example 3.

[0026] The rot rate at the fruit stalk, total rot rate, and water loss rate of Akizuki pears in Examples 1-3 and Comparative Examples 1-3 of this invention were tested, and the results are shown in Table 1: Table 1 Comparison of storage effects between each embodiment and the comparative example

[0027] As shown in Table 1, the rot rate at the fruit stalk of the Akizuki pears treated in Examples 1-3 of this invention was significantly lower than that in Comparative Example 1 after 120 days of storage. This indicates that pre-harvest spraying effectively kills pathogens lurking in hidden areas such as crevices in the fruit stalk, reducing the occurrence of rot at the fruit stalk from the source. The rot rate at the fruit stalk and the total rot rate in Examples 1-3 were both significantly lower than those in Comparative Example 2, indicating that post-harvest immersion treatment has an irreplaceable role in sterilization and protection of the fruit surface, further enhancing the protective effect on the peel surface. The total rot rate and water loss rate of Examples 1-3 were better than those in Comparative Examples 1 and 2, indicating that the tiered combination of pre-harvest spraying and post-harvest immersion produced a synergistic effect, and both are indispensable. Comparative Example 3, without any treatment, showed significantly higher rot and water loss rates after 120 days of storage compared to the other treatment groups. The method of this invention can significantly improve the medium- and long-term storage and preservation effect of Akizuki pears. After 120 days of storage, there are basically no problems such as softening of the flesh, deterioration, or blackening of the peel. The rot rate at the stem can be controlled within 0.2%, the total rot rate can be controlled within 0.5%, and the water loss rate can be controlled within 3.5%.

[0028] This invention has illustrated its principles and implementation methods using specific examples. The descriptions of these embodiments are merely illustrative of the method and its core ideas; furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the principles of this invention. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. An integrated method for pre- and post-harvest tiered pesticide application for preservation and freshness, characterized in that, Includes the following steps: (1) Pre-harvest spraying treatment: 7 to 10 days before the harvest of Akizuki pear, spray the whole fruit plant with the spray solution containing melatonin and chitosan oligosaccharide. When spraying, focus on covering the base of the fruit stalk, the calyx folds and the joint of the fruit shoulder. (2) Harvesting and sorting: When harvesting, retain the fruit stem and stalk, and remove mechanically damaged fruit and fruit with pests and diseases; (3) Post-harvest soaking treatment: After harvesting, the Akizuki pears are soaked in a preservative solution for 5 to 10 minutes under light-proof conditions. The preservative solution contains melatonin, citric acid, ferrous sulfate, calcium chloride and surfactant. After taking them out, they are dried. (4) Controlled atmosphere storage: Place the soaked Akizuki pears in a low-temperature environment and store them under artificial controlled atmosphere conditions by filling them with 1-methylcyclopropene.

2. The integrated pre-harvest and post-harvest tiered pesticide application method for preservation and freshness according to claim 1, characterized in that, In step (1), the concentration of melatonin in the pre-harvest spray solution is 50-200 μmol / L, and the mass percentage concentration of chitosan oligosaccharide is 0.05%-0.2%.

3. The integrated pre-harvest and post-harvest tiered pesticide application method for preservation and freshness according to claim 1, characterized in that, The spraying time in step (1) is selected to be in the evening or on a cloudy day, and the amount of spraying is to spray until the fruit surface is evenly moistened and no dripping occurs.

4. The integrated pre-harvest and post-harvest tiered pesticide application method for preservation and freshness according to claim 1, characterized in that, Step (1) involves pre-harvest spraying using a backpack sprayer or an orchard wind-assisted sprayer for directional spraying.

5. The integrated pre-harvest and post-harvest tiered pesticide application method for preservation and freshness according to claim 1, characterized in that, The preservative solution in step (3) comprises the following concentrations of raw materials: melatonin 0.5-2 mmol / L, citric acid 0.05-0.2 g / L, ferrous sulfate 0.02-0.3 g / L, calcium chloride 0.5-2 g / L, surfactant 0.1-0.5 g / L, and the remainder is water.

6. The integrated pre-harvest and post-harvest tiered pesticide application method for preservation and freshness according to claim 1, characterized in that, The surfactant in step (3) is either laurate or monooleate.

7. The integrated pre-harvest and post-harvest tiered pesticide application method for preservation and freshness according to claim 1, characterized in that, The low temperature environment described in step (4) is 4-10℃ and the relative humidity is 85%-90%.

8. The integrated pre-harvest and post-harvest tiered pesticide application method for preservation and freshness according to claim 1, characterized in that, The artificial atmosphere described in step (4) consists of 87%–97% nitrogen, 0.2%–8% oxygen, and 1%–5% carbon dioxide.

9. The integrated pre-harvest and post-harvest tiered pesticide application method for preservation and freshness according to claim 1, characterized in that, The concentration of 1-methylcyclopropene in step (4) is 0.5 to 2 μL / L.

10. The integrated pre-harvest and post-harvest tiered pesticide application method for preservation and freshness according to claim 1, characterized in that, The soaking time of the preservative solution in step (3) is 8 to 10 minutes.

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