Preservation method for harvested agricultural products and application of preservation method

Abstract

The invention provides a preservation method for harvested agricultural products and application of the preservation method, and belongs to the technical field of agricultural product preservation. The preservation method for the harvested agricultural products comprises the following steps: pre-cooling the harvested agricultural products, and treating the agricultural products with ozone during the pre-cooling period; and then performing magnetic field combined controlled atmosphere storage on the agricultural products subjected to ozone treatment. The method firstly kills or inhibits pathogenic bacteria to infect diseases through ozone, then combines the magnetic field action with the controlled atmosphere storage technology, inhibits the aging of the agricultural products, achieves the effect of prolonging the storage period of the agricultural products, and improves the quality of the agricultural products compared with the traditional storage technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural product preservation, and in particular relates to a method for preserving agricultural products after harvest and an application thereof. Background Art

[0002] With rising living standards, consumers are increasingly favoring high-quality, flavor-retaining agricultural products like edible fungi and fruits. Consequently, the research, development, and application of physical preservation technologies are gaining popularity. Technologies such as ozone, controlled atmosphere, and magnetic fields are being studied and applied in depth.

[0003] Ozone is a strong oxidant that can destroy microbial cell walls and kill or inhibit bacterial and fungal growth on the surfaces of agricultural products. However, using it at excessive concentrations or for extended periods can destroy nutrients, alter flavor, and change texture. Agricultural products exposed to an external magnetic field undergo a series of physiological and even genetic changes, resulting in various biomagnetic effects that preserve freshness. However, magnetic field preservation technology currently has some limitations. For example, different types of agricultural products and foods have varying requirements for magnetic field intensity and duration, requiring extensive experimentation to determine optimal preservation parameters. Controlled atmosphere storage primarily controls the atmospheric environment of agricultural products to inhibit their respiratory metabolism, thereby extending their postharvest storage period. However, prolonged controlled atmosphere storage prevents the expulsion of undesirable gases generated by the agricultural products, leading to their accumulation. Therefore, developing a method to improve the quality and storage time of agricultural products is a currently unresolved technical challenge. Currently, there is no application of ozone, magnetic fields, and controlled atmosphere preservation technology in the postharvest preservation of agricultural products. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for preserving agricultural products after harvest and its application. The present invention uses ozone sterilization in the pre-cooling process to inhibit infectious diseases of agricultural products after harvest; in the storage process, a magnetic field and controlled atmosphere storage are used in combination to regulate the physiological changes of agricultural products after harvest, thereby extending the storage period of agricultural products.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preserving agricultural products after harvest, comprising the following steps: precooling the agricultural products and treating them with ozone during the cooling process; and then storing the ozone-treated agricultural products in a magnetic field combined with controlled atmosphere.

[0007] Preferably, the precooling temperature is 0.5-4.5°C, and the precooling time is 8-16 hours.

[0008] Preferably, the ozone treatment method includes: during the pre-cooling period, continuously using ozone shock for 3-6 minutes every 25-35 minutes.

[0009] Preferably, the ozone concentration is 0.3-3.5 μL / L.

[0010] Preferably, the treatment method of the magnetic field combined with controlled atmosphere storage includes: transferring the ozone-treated agricultural products into a magnetic field turnover basket and then performing controlled atmosphere storage.

[0011] Preferably, the intensity of the magnetic field is 1-7 mT.

[0012] Preferably, the parameters of the controlled atmosphere storage include: O2 volume content of 1-8%, CO2 volume content of 3-18%, N2 volume content of 75-94%, temperature of 0-5°C and humidity of 85-98%.

[0013] Preferably, the agricultural products include vegetables and fruits.

[0014] Preferably, the vegetables include tomatoes, shiitake mushrooms, and red-stemmed bamboo fungus; and the fruits include honey plums, kiwis, blueberries, and apples.

[0015] The present invention also provides application of the method for preserving agricultural products after harvest in extending the storage time of agricultural products and improving the quality of agricultural products.

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

[0017] The present invention combines pre-cooling with ozone treatment, effectively saving processing time while also reducing agricultural product respiration and minimizing the incidence of post-harvest infectious diseases. The combined application of a magnetic field and controlled atmosphere during subsequent storage significantly outperforms the effects of these two physical preservation methods alone, without leaving any chemical residue. The present invention's post-harvest agricultural product preservation method extends the storage period and improves agricultural product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an example diagram of a magnetic field turnover basket with 8 magnets fixed on both sides in the embodiment.

[0019] Figure 2 Schematic diagram of the 1-3 mT magnetic field turnover basket in Example 7. DETAILED DESCRIPTION

[0020] The present invention provides a method for preserving agricultural products after harvest, comprising the steps of precooling the agricultural products and treating them with ozone; and then storing the ozone-treated agricultural products in a magnetic field combined with controlled atmosphere storage. The method harvests agricultural products that meet harvesting standards, dissipates field heat in a cool, shady location, and then precools them.

[0021] In the present invention, the precooling temperature is 0.5-4.5°C, preferably 1-4°C, more preferably 1.5-2°C or 2.5-4°C; the precooling time is 8-16h, preferably 9-15h, more preferably 10-12h or 13-14h.

[0022] In the present invention, ozone at a concentration of 0.3-3.5 μL / L is used to treat agricultural products during pre-cooling. The concentration of ozone in the present invention is preferably 0.5-2 μL / L, more preferably 0.6-1 μL / L or 1.2-2 μL / L. The ozone treatment method of the present invention includes: continuously using ozone shock for 3-6 minutes every 25-35 minutes; preferably, the ozone treatment method includes: continuously using ozone shock for 3.5-4.5 minutes every 28-32 minutes; more preferably, the ozone treatment method includes: continuously using ozone shock for 5 minutes every 30 minutes. The time of ozone treatment in the present invention is 8-16 hours, preferably 9-15 hours, more preferably 10-12 hours or 13-14 hours. The appropriate ozone shock concentration of the present invention has a good preservation effect on agricultural products. When the ozone shock concentration is too high (≥3.5 μL / L), the rot rate of kiwifruit after storage for 30 days is higher than that of the blank control group. It is speculated that the higher concentration of ozone destroys the cell membrane structure of the fruit and accelerates decay.

[0023] In the present invention, the magnetic field combined with controlled atmosphere treatment includes: transferring the ozone-treated agricultural products into a magnetic field turnover basket, and then performing controlled atmosphere storage. The magnetic field turnover basket of the present invention is a turnover basket equipped with ferrite magnets. The intensity of the magnetic field of the present invention is 1-7mT, preferably 1-3mT, 3-6mT or 4-7mT. The magnetic field intensity of the present invention is generated by the ferrite magnets, and the magnitude of the magnetic field intensity is determined by the size and shape of the ferrite magnets. The production of the magnetic field turnover basket of the present invention includes: placing ferrite magnets of different numbers and sizes on the long sides of an ordinary fruit basket based on the required magnetic field intensity, thereby forming a "magnetic field turnover basket" with different magnetic field intensities. The appropriate magnetic field concentration of the present invention has a good preservation effect on agricultural products. When the magnetic field concentration is too high, the rot rate of kiwifruit after 30 days of storage is higher than that of the blank control group. It is speculated that the stronger magnetic field will disrupt the metabolism of the fruit itself.

[0024] In the present invention, the storage parameters of the controlled atmosphere include: O2 volume content of 1-8%, CO2 volume content of 3-18%, N2 volume content of 75-94%, temperature of 0-5°C and humidity of 85-98%; preferably, the storage parameters of the controlled atmosphere include: O2 volume content of 1.5-6%, CO2 volume content of 4-16%, N2 volume content of 78-93%, temperature of 0.5-4.5°C and humidity of 88-97%; further preferably, the storage parameters of the controlled atmosphere include: O2 volume content of 2% or 3% or 4% or 5%, CO2 volume content of 5% or 6% or 10% or 15%, N2 volume content of 80% or 81% or 82% or 85% or 90% or 92%, temperature of 1.5-2°C or 2.5-3.5°C and humidity of 90-95%. During controlled atmosphere storage, the appropriate O2, CO2 and N2 contents have a good preservation effect on agricultural products. Using a higher concentration of CO2 (≥18%) will cause honey plums to have a distinct alcohol smell after 30 days. It is speculated that the higher concentration of CO2 causes anaerobic respiration in the fruit.

[0025] In the present invention, the agricultural products include but are not limited to vegetables and fruits. The vegetables include but are not limited to tomatoes, shiitake mushrooms, and red bamboo fungus; the fruits include but are not limited to honey plums, kiwis, blueberries, and apples.

[0026] The present invention also provides application of the method for preserving agricultural products after harvest in extending the storage time of agricultural products and improving the quality of agricultural products.

[0027] In the present invention, unless otherwise specified, all equipment or materials are commercially available products well known to those skilled in the art.

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] The detection method involved in the embodiment of the present invention is as follows:

[0030] (1) Hardness test method: The hardness of agricultural products was measured using a Shimadzu EZ-SX texture analyzer. A P / 2 probe with a 2 mm diameter was used. The product was punctured at the equator, turned 180°, and punctured again. The penetration speed was set to 2.00 mm / sec before, during, and after penetration. The penetration depth was 10 mm (for honey plum, kiwi, apple, and tomato) and 6 mm (for blueberry). The unit was N (n = 18). The hardness values recorded on the instrument were recorded and counted.

[0031] (2) Shear force test method: A Shimadzu EZ-SX texture analyzer was used to test the shear force of agricultural products. A 2 mm TA / LKB cutter probe was used for the shear force test. The texture analyzer was set up with the following parameters: shear force mode, test speed of 5 mm / s, post-test speed of 15 mm / s, distance of 50 mm (for shiitake mushrooms and red-stemmed bamboo fungus), and the unit was N (n = 18). The shear force values recorded on the instrument were recorded and counted.

[0032] (3) Rot rate detection method: The statistical method was used to determine the rate. The samples with lesions, hyphae and obvious softening and decay were recorded as rotten samples, n = 18, and the rate was calculated according to the following formula: Rot rate = number of rotten samples (pieces) / total number (pieces) × 100%.

[0033] (4) Soluble solids (SSC) test method: refer to NY / T 2637-2014 “Determination of soluble solids content of fruits and vegetables—Refractometer method”, and use PAL-1 mini digital refractometer for determination (n=18), the unit is %.

[0034] (5) Browning degree: Approximately 2 g of tissue mixture was ground in an ice bath, 8 mL of 0.2 mol / L sodium phosphate buffer (pH 6.8) was added, and the mixture was stored at 4°C for 15 min. The mixture was centrifuged at 24,000 × g, and the supernatant was collected. The absorbance at 420 nm was measured using a UV-visible spectrophotometer (Cary 60, Agilent, Santa Clara, CA, USA).

[0035] Example 1: Method for preserving honey plums after harvest

[0036] (1) Harvesting: Harvest honey plum fruits that meet the harvesting standards (SSC: 13%-15%, hardness: 10.5-12.5N) and place them in a cool place to dissipate the field heat.

[0037] (2) Precooling: Transfer the honey plums to a cold storage and precool them at 2°C for 12 hours. Simultaneously, use continuous ozone (2 μL / L) for 5 minutes, once every 30 minutes, and ozone treatment for 12 hours.

[0038] (3) Magnetic field treatment: The honey plum fruits treated in step (2) were transferred to a turnover basket (500 mm long × 350 mm wide × 300 mm high) equipped with a ferrite magnet with a magnetic field strength of 3-6 mT; the preparation method of the 3-6 mT magnetic field turnover basket is as follows: 8 square ferrite magnets (100 mm long × 50 mm wide × 10 mm thick) were fixed on both sides of the 500 mm long side of an ordinary turnover basket (500 mm long × 350 mm wide × 300 mm high).

[0039] (4) Storage: The 3-6 mT magnetic field turnover basket containing the honey plums was directly transferred to a controlled atmosphere storage facility for controlled atmosphere storage. The parameters of the controlled atmosphere storage facility were set to: O2 volume content of 3%, CO2 volume content of 15%, N2 volume content of 82%, temperature of 2±0.5℃ and humidity of 90-95%.

[0040] Comparative Example 1

[0041] The steps are the same as those in Example 1, except that ozone treatment is not performed in the precooling stage of step (2). After precooling, the mixture is immersed in 1 g / L sodium dehydroacetate solution for 30 seconds, naturally drained, and then transferred to a magnetic field turnover basket.

[0042] Comparative Example 2

[0043] The steps are the same as those in Example 1, except that a common turnover basket is used in step (3).

[0044] Comparative Example 3

[0045] The steps are the same as those in Example 1, except that in step (4), controlled atmosphere storage is not used during the storage stage, and low-temperature storage at 2±0.5°C is performed.

[0046] Comparative Example 4

[0047] The steps are the same as those in Example 1, except that a turnover basket with a high magnetic field strength (9-12 mT) is used in step (3). The 9-12 mT magnetic field turnover basket is prepared as follows: 8 square ferrite magnets (100 mm long × 50 mm wide × 20 mm thick) are fixed on both sides of a 500 mm long turnover basket (500 mm long × 350 mm wide × 300 mm high).

[0048] After 60 days of storage, the decay rate, hardness and soluble solid content of the honey plum fruits stored in Example 1 and Comparative Examples 1-4 were measured. The results are shown in Table 1.

[0049] Table 1 Effect of each treatment group on the preservation of honey plum

[0050] Grouping Decay rate (%) Hardness (N) SSC (%) Example 1 5.65±0.14 9.39±0.32 14.04±0.38 Comparative Example 1 22.98±3.74 7.12±0.26 15.90±0.25 Comparative Example 2 19.17±4.46 6.08±0.23 16.64±0.16 Comparative Example 3 18.48±4.51 7.85±0.14 15.20±0.23 Comparative Example 4 24.31±2.34 5.61±0.18 16.82±0.17

[0051] Comparisons in Table 1 show that ozone + controlled atmosphere combined with magnetic field treatment (Example 1) exhibited the best preservation effect on honey plums, maintaining the lowest decay rate and soluble solids content, and the highest firmness after 60 days of storage. Overall, the overall preservation effect of all treatments on honey plums ranked as follows: ozone + controlled atmosphere combined with magnetic field treatment (Example 1) > ozone + magnetic field treatment (Comparative Example 3) > magnetic field + controlled atmosphere (Comparative Example 1) > ozone + controlled atmosphere (Comparative Example 2) > ozone + controlled atmosphere + high-intensity magnetic field (Comparative Example 4).

[0052] Example 2 Kiwifruit (Guichang) Fresh-keeping Method After Harvest

[0053] (1) Harvesting: Harvest kiwifruit that meets the harvesting standards (SSC: 7.5%-8.5%, hardness: 35-45N) and place in a cool place to dissipate field heat.

[0054] (2) Precooling: The kiwifruit was transferred to a cold storage and precooled at 2°C for 12 h. At the same time, ozone was continuously applied (2 μL / L) for 5 min, once every 30 min, for a total of 12 h.

[0055] (3) Magnetic field treatment: The kiwifruit treated in step (2) was transferred to a magnetic field turnover basket (500 mm long × 350 mm wide × 300 mm high) equipped with a ferrite magnet with a magnetic field strength of 3-6 mT; the preparation of the 3-6 mT magnetic field turnover basket was the same as in Example 1.

[0056] (4) Storage: The 3-6 mT magnetic field turnover baskets containing kiwifruit were directly transferred to a controlled atmosphere storage facility for controlled atmosphere storage. The controlled atmosphere storage parameters were set to: O2 volume content of 5%, CO2 volume content of 15%, N2 volume content of 80%, temperature of 2±0.5℃, and humidity of 90-95%.

[0057] Comparative Example 5

[0058] The steps are the same as those in Example 2, except that ozone treatment is not performed in the precooling stage of step (2). After precooling, the mixture is immersed in a 1 g / L sodium dehydroacetate solution for 30 seconds, naturally drained, and then transferred to a magnetic field turnover basket.

[0059] Comparative Example 6

[0060] The steps are the same as those in Example 2, except that a common turnover basket is used in step (3).

[0061] Comparative Example 7

[0062] The steps are the same as those in Example 2, except that in step (4), controlled atmosphere storage is not used during the storage stage, and low-temperature storage at 2±0.5°C is performed.

[0063] Comparative Example 8

[0064] The steps are the same as those in Example 2, except that a turnover basket with a high magnetic field strength (12-15 mT) is used in step (3). The 12-15 mT turnover basket is prepared as follows: 8 square ferrite magnets (100 mm long × 50 mm wide × 25 mm thick) are fixed on both sides of a 500 mm long turnover basket (500 mm long × 350 mm wide × 300 mm high).

[0065] After 120 days of storage, the decay rate, hardness and soluble solid content of the kiwifruit fruits stored in Example 2 and Comparative Examples 5-8 were measured. The results are shown in Table 2.

[0066] Table 2 Effect of each treatment group on the preservation of kiwi fruit

[0067] Grouping Decay rate (%) Hardness (N) SSC (%) Example 2 4.88±0.45 27.43±0.83 14.53±0.21 Comparative Example 5 23.03±1.69 19.20±0.34 13.13±0.29 Comparative Example 6 29.11±0.76 16.91±0.35 11.23±0.29 Comparative Example 7 26.49±0.65 17.22±0.15 12.17±0.10 Comparative Example 8 33.02±0.86 15.44±0.28 10.86±0.24

[0068] As shown in Table 2, ozone + controlled atmosphere combined with a magnetic field (Example 2) exhibited the best preservation effect on kiwifruit, maintaining the lowest decay rate and the highest firmness and soluble solids content after 120 days of storage. Overall, the overall preservation effect of all treatments on kiwifruit was ranked as follows: ozone + controlled atmosphere combined with a magnetic field (Example 2) > magnetic field + controlled atmosphere (Comparative Example 5) > ozone + magnetic field (Comparative Example 7) > ozone + controlled atmosphere (Comparative Example 6) > ozone + controlled atmosphere + high-intensity magnetic field (Comparative Example 8).

[0069] Example 3 Blueberry (Brilliant) Post-harvest Fresh-keeping Method

[0070] (1) Harvesting: blueberry fruits that meet the harvesting standards (SSC: 12-13%, hardness: 3.5-4.5N) are harvested and placed in small fruit boxes (230mm long × 150mm wide × 55mm high) in a cool place to dissipate field heat;

[0071] (2) Precooling: The blueberries were transferred to a cold storage and precooled at 2°C for 12 h. At the same time, ozone (1 μL / L) was used for shock for 5 min, once every 30 min, and the ozone treatment lasted for 12 h.

[0072] (3) Magnetic field treatment: The blueberry fruits packed in small fruit boxes were uniformly transferred to a magnetic field turnover basket (500 mm long × 350 mm wide × 300 mm high) equipped with a ferrite magnet with a magnetic field strength of 1-3 mT. The preparation method of the 1-3 mT magnetic field turnover basket is as follows: 8 square ferrite magnets (100 mm long × 20 mm wide × 5 mm thick) were fixed on both sides of the 500 mm long side of an ordinary turnover basket (500 mm long × 350 mm wide × 300 mm high).

[0073] (4) Storage: The 1-3 mT magnetic field turnover baskets containing blueberries were directly transferred to a controlled atmosphere storage facility for controlled atmosphere storage. The controlled atmosphere storage parameters were set to 4% O2 volume content, 15% CO2 volume content, 81% N2 volume content, temperature 2±0.5°C, and humidity 90-95%.

[0074] Comparative Example 9

[0075] The steps are the same as those in Example 3, except that ozone treatment is not performed in the precooling stage of step (2). After precooling, the mixture is immersed in a 1 g / L sodium dehydroacetate solution for 30 seconds, drained naturally, and then transferred to a magnetic field turnover basket.

[0076] Comparative Example 10

[0077] The steps are the same as those in Example 3, except that an ordinary turnover basket is used in step (3).

[0078] Comparative Example 11

[0079] The steps are the same as those in Example 3, except that in step (4), controlled atmosphere storage is not used during the storage stage, and low-temperature storage at 2±0.5°C is performed.

[0080] Comparative Example 12

[0081] The steps are the same as those in Example 3, except that a turnover basket with a high magnetic field strength (9-12 mT) is used in step (3). The preparation of the turnover basket with a magnetic field strength of 9-12 mT is the same as that in Comparative Example 4.

[0082] After 10 days of storage, the decay rate, firmness and soluble solids content of the blueberry fruits stored in Example 3 and Comparative Examples 9-12 were measured. The results are shown in Table 3.

[0083] Table 3 Effect of each treatment group on the preservation of blueberries

[0084]

[0085]

[0086] Comparisons in Table 3 show that ozone + controlled atmosphere combined with a magnetic field (Example 3) achieved the best blueberry preservation results, maintaining the lowest decay rate after 10 days and the highest firmness and soluble solids content. Overall, the overall blueberry preservation performance ranking of all treatments was: ozone + controlled atmosphere combined with a magnetic field (Example 3) > magnetic field + controlled atmosphere (Comparative Example 9) > ozone + magnetic field (Comparative Example 11) > ozone + controlled atmosphere (Comparative Example 10) > ozone + controlled atmosphere + high-intensity magnetic field (Comparative Example 12).

[0087] Example 4 Apple (Red Fuji) Fresh-keeping Method After Harvest

[0088] (1) Harvesting: Apple fruits that meet the harvesting standards (SSC: 12%-14%, hardness: 80-90N) are harvested and placed in a cool place to dissipate the field heat.

[0089] (2) Precooling: apples were transferred to a cold storage and precooled at 1°C for 12 h. At the same time, ozone was continuously applied (2 μL / L) for 5 min, once every 30 min, for a total of 12 h.

[0090] (3) Magnetic field treatment: The apple fruits were transferred to a magnetic field turnover basket (500 mm long × 350 mm wide × 300 mm high) equipped with a ferrite magnet with a magnetic field strength of 4-7 mT. The preparation method of the 4-7 mT magnetic field turnover basket is as follows: 8 square ferrite magnets (100 mm long × 50 mm wide × 12 mm thick) were fixed on both sides of the 500 mm long side of an ordinary turnover basket (500 mm long × 350 mm wide × 300 mm high).

[0091] (4) Storage: The 4-7 mT magnetic field turnover basket containing apples was directly transferred to a controlled atmosphere storage room for controlled atmosphere storage. The parameters of the controlled atmosphere storage room were set as follows: O2 volume content of 3%, CO2 volume content of 15%, N2 volume content of 82%, temperature of 1±0.5℃ and humidity of 90-95%.

[0092] Comparative Example 13

[0093] The steps are the same as those in Example 4, except that ozone treatment is not performed in the precooling stage of step (2). After precooling, the mixture is soaked in 1 g / L sodium dehydroacetate for 30 seconds, drained naturally, and then transferred to a magnetic field turnover basket.

[0094] Comparative Example 14

[0095] The steps are the same as those in Example 4, except that an ordinary turnover basket is used in step (3).

[0096] Comparative Example 15

[0097] The steps are the same as those in Example 4, except that in step (4), controlled atmosphere storage is not used during the storage stage, and low-temperature storage at 1±0.5°C is performed.

[0098] Comparative Example 16

[0099] The steps are the same as those in Example 4, except that a turnover basket with a high magnetic field strength (12-15 mT) is used in step (3). The turnover basket with a 12-15 mT magnetic field is the same as that in Comparative Example 8.

[0100] After 120 days of storage, the decay rate, firmness and soluble solid content of the apple fruits stored in Example 4 and Comparative Examples 13-16 were measured. The results are shown in Table 4.

[0101] Table 4 Effect of each treatment group on the preservation of apples

[0102] Grouping Decay rate (%) Hardness (N) SSC (%) Example 4 3.15±0.18 75.73±2.56 12.33±0.42 Comparative Example 13 5.33±0.81 64.22±1.22 10.92±0.57 Comparative Example 14 8.05±0.23 40.05±2.76 8.84±0.32 Comparative Example 15 5.94±0.12 58.41±2.28 9.65±0.41 Comparative Example 16 10.14±0.16 36.48±2.64 8.01±0.24

[0103] Comparing the results in Table 4, ozone + controlled atmosphere combined with a magnetic field (Example 4) demonstrated the best preservation effect on apples, maintaining the lowest decay rate after 120 days and the highest firmness and soluble solids content. Overall, the overall preservation effect of all treatments on apples ranked as follows: ozone + controlled atmosphere combined with a magnetic field (Example 4) > magnetic field + controlled atmosphere (Comparative Example 13) > ozone + magnetic field (Comparative Example 15) > ozone + controlled atmosphere (Comparative Example 14) > ozone + controlled atmosphere + high-intensity magnetic field (Comparative Example 16).

[0104] Example 5: Method for preserving tomatoes (Millennium) after harvest

[0105] (1) Harvesting: Harvest tomato fruits that meet the harvesting standards (red ripe stage) and dissipate the field heat in a cool place.

[0106] (2) Precooling: Transfer the tomatoes to a cold storage and precool them at 4°C for 12 h. Simultaneously, use continuous ozone (2 μL / L) for 5 min, once every 30 min, and ozone treatment for 12 h.

[0107] (3) Magnetic field treatment: The tomato fruits were transferred to a magnetic field turnover basket (500 mm long × 350 mm wide × 300 mm high) equipped with a ferrite magnet with a magnetic field strength of 3-6 mT; the preparation method of the 3-6 mT magnetic field turnover basket was the same as that in Example 1.

[0108] (4) Storage: The 3-6 mT magnetic field turnover baskets containing tomatoes were directly transferred to a controlled atmosphere storage facility for controlled atmosphere storage. The controlled atmosphere storage parameters were set as follows: O2 volume content of 5%, CO2 volume content of 10%, N2 volume content of 85%, temperature of 4±0.5°C, and humidity of 90-95%.

[0109] Comparative Example 17

[0110] The steps are the same as those in Example 5, except that ozone treatment is not performed in the precooling stage of step (2). After precooling, the mixture is immersed in a 1 g / L sodium dehydroacetate solution for 30 seconds, naturally drained, and then transferred to a magnetic field turnover basket.

[0111] Comparative Example 18

[0112] The steps are the same as those in Example 5, except that an ordinary turnover basket is used in step (3).

[0113] Comparative Example 19

[0114] The same as Example 5, except that in step (4), controlled atmosphere storage is not used during the storage stage, and low-temperature storage at 4±0.5°C is performed.

[0115] Comparative Example 20

[0116] The steps are the same as those in Example 5, except that a turnover basket with a high magnetic field strength (9-12 mT) is used in step (3). The preparation of the turnover basket with a magnetic field strength of 9-12 mT is the same as that in Comparative Example 4.

[0117] After 20 days of storage, the decay rate, hardness and soluble solid content of the tomato fruits stored in Example 5 and Comparative Examples 17-20 were measured. The results are shown in Table 5.

[0118] Table 5 Effect of each treatment group on the preservation of tomatoes

[0119] Grouping Decay rate (%) Hardness (N) SSC (%) Example 5 5.54±0.45 10.48±0.31 3.81±0.12 Comparative Example 17 6.33±0.15 8.22±0.62 3.22±0.17 Comparative Example 18 9.23±0.14 6.02±0.41 2.44±0.22 Comparative Example 19 7.93±0.41 7.88±0.55 2.95±0.04 Comparative Example 20 12.12±0.21 5.27±0.15 2.10±0.08

[0120] As shown in Table 5, ozone + controlled atmosphere combined with a magnetic field (Example 5) exhibited the best preservation effect on tomatoes, maintaining the lowest decay rate and the highest firmness and soluble solids content after 20 days of storage. Overall, the overall preservation effect of all treatments on tomatoes was ranked as follows: ozone + controlled atmosphere combined with a magnetic field (Example 5) > magnetic field + controlled atmosphere (Comparative Example 17) > ozone + magnetic field (Comparative Example 19) > ozone + controlled atmosphere (Comparative Example 18) > ozone + controlled atmosphere + high-intensity magnetic field (Comparative Example 20).

[0121] Example 6 Post-harvest preservation method for Lentinus edodes (L808)

[0122] (1) Harvesting: Harvest mushrooms that meet the harvesting standards (complete mushroom bodies and bright color) and place them in a cool place to dissipate the field heat.

[0123] (2) Precooling: Shiitake mushrooms were transferred to a cold storage and precooled at 4°C for 12 h. At the same time, ozone was continuously applied (0.5 μL / L) for 5 min, once every 30 min, for a total of 12 h.

[0124] (3) Magnetic field treatment: The mushrooms were transferred to a magnetic field turnover basket (500 mm long × 350 mm wide × 300 mm high) equipped with a ferrite magnet with a magnetic field strength of 1-3 mT; the preparation of the 1-3 mT magnetic field turnover basket was the same as in Example 3.

[0125] (4) Storage: The 1-3 mT magnetic field turnover baskets containing shiitake mushrooms were directly transferred to a controlled atmosphere storage facility for controlled atmosphere storage. The parameters of the controlled atmosphere storage facility were set to: O2 volume content of 2%, CO2 volume content of 6%, N2 volume content of 92%, temperature of 4±0.5℃, and humidity of 90-95%.

[0126] Comparative Example 21

[0127] The steps are the same as those in Example 6, except that ozone treatment is not performed in the precooling stage of step (2). After precooling, the mixture is immersed in a 1 g / L sodium dehydroacetate solution for 30 seconds, naturally drained, and then transferred to a magnetic field turnover basket.

[0128] Comparative Example 22

[0129] The steps are the same as those in Example 6, except that an ordinary turnover basket is used in step (3).

[0130] Comparative Example 23

[0131] The steps are the same as those in Example 6, except that in step (4), controlled atmosphere storage is not used during the storage stage, and low-temperature storage at 4±0.5°C is performed.

[0132] Comparative Example 24

[0133] The steps are the same as those in Example 6, except that a high magnetic field strength (6-9 mT) turnover basket is used in step (3). The 6-9 mT magnetic field turnover basket is prepared as follows: 8 square ferrite magnets (100 mm long × 50 mm wide × 15 mm thick) are fixed on both sides of a 500 mm long turnover basket (500 mm long × 350 mm wide × 300 mm high);

[0134] After 20 days of storage, the decay rate, shear force and browning degree of the shiitake mushrooms stored in Example 6 and Comparative Examples 21-24 were measured. The results are shown in Table 6.

[0135] Table 6 Preservation effect of each treatment group on shiitake mushrooms

[0136] Grouping Decay rate (%) Shear force (N) Browning degree Example 6 8.64±0.45 61.48±0.14 0.32±0.02 Comparative Example 21 9.14±0.85 42.14±0.12 0.55±0.08 Comparative Example 22 12.34±0.67 33.42±0.48 0.74±0.06 Comparative Example 23 10.93±0.38 25.24±0.85 0.61±0.04 Comparative Example 24 14.33±0.54 22.45±0.21 0.79±0.05

[0137] Comparisons in Table 6 show that ozone + controlled atmosphere combined with a magnetic field (Example 6) achieved the best preservation effect on shiitake mushrooms, maintaining the lowest decay rate and browning after 20 days, and maintaining the highest shear force. Overall, the overall preservation effect of all treatments on shiitake mushrooms ranked as follows: ozone + controlled atmosphere combined with a magnetic field (Example 6) > magnetic field + controlled atmosphere (Comparative Example 21) > ozone + magnetic field (Comparative Example 23) > ozone + controlled atmosphere (Comparative Example 22) > ozone + controlled atmosphere + high-intensity magnetic field (Comparative Example 24).

[0138] Example 7: Method for preserving red bamboo fungus after harvesting

[0139] (1) Harvesting: Harvest the red-stemmed bamboo fungus that meets the harvesting standards (complete fungus body and bright color) and dissipate the field heat in a cool place.

[0140] (2) Precooling: Transfer the red stem bamboo fungus to a cold storage and precool it at 2℃ for 12 hours. At the same time, use continuous ozone (2μL / L) for 5 minutes, once every 30 minutes, and ozone treatment for 12 hours.

[0141] (3) Magnetic field treatment: The red-stemmed bamboo fungus was transferred to a magnetic field turnover basket (370 mm long × 300 mm wide × 90 mm high) equipped with a ferrite magnet with a magnetic field strength of 1-3 mT. The preparation method of the 1-3 mT magnetic field turnover basket is as follows: three square ferrite magnets (100 mm long × 50 mm wide × 5 mm thick) were fixed on both sides of the 370 mm long section of an ordinary turnover basket (370 mm long × 300 mm wide × 90 mm high).

[0142] (4) Storage: The 1-3 mT magnetic field turnover basket containing red stem bamboo fungus was directly transferred to a controlled atmosphere storage for controlled atmosphere storage. The parameters of the controlled atmosphere storage were set as follows: O2 volume content of 5%, CO2 volume content of 5%, N2 volume content of 90%, temperature of 2±0.5℃ and humidity of 90-95%.

[0143] Comparative Example 25

[0144] The steps are the same as those in Example 7, except that ozone treatment is not performed in the precooling stage of step (2). After precooling, the mixture is immersed in 1 g / L sodium dehydroacetate solution for 30 seconds, drained naturally, and then transferred to a magnetic field turnover basket.

[0145] Comparative Example 26

[0146] The steps are the same as those in Example 7, except that an ordinary turnover basket is used in step (3).

[0147] Comparative Example 27

[0148] The steps are the same as those in Example 7, except that in step (4), controlled atmosphere storage is not used during the storage stage, and low-temperature storage at 2±0.5°C is performed.

[0149] Comparative Example 28

[0150] The steps are the same as those in Example 7, except that a turnover basket with a high magnetic field strength (6-9 mT) is used in step (3). The preparation of the turnover basket with a 6-9 mT magnetic field is the same as that in Comparative Example 24.

[0151] After 12 days of storage, the decay rate, shear force and browning degree of the red-stalked bamboo fungus stored in Example 7 and Comparative Examples 25-28 were measured. The results are shown in Table 7.

[0152] Table 7 The preservation effect of each treatment group on Dictyophora rubra

[0153] Grouping Decay rate (%) Shear force (N) Browning degree Example 7 9.64±0.25 8.37±0.84 4.29±0.12 Comparative Example 25 18.14±0.65 9.32±0.65 5.86±0.08 Comparative Example 26 32.34±0.91 12.91±1.05 7.45±0.02 Comparative Example 27 28.33±1.22 10.53±0.24 6.39±0.04 Comparative Example 28 36.12±1.04 14.11±0.84 7.88±0.03

[0154] From the comparison in Table 7, it can be seen that ozone + controlled atmosphere combined with magnetic field treatment (Example 7) has the best preservation effect on red stem bamboo fungus, maintaining the lowest decay rate, shear force, and browning degree after 12 days. Overall, among all the treatments, the comprehensive preservation effect on red stem bamboo fungus is ranked as ozone + controlled atmosphere combined with magnetic field treatment (Example 7) > magnetic field + controlled atmosphere (Comparative Example 25) > ozone + magnetic field treatment (Comparative Example 27) > ozone + controlled atmosphere (Comparative Example 26) > ozone + controlled atmosphere + high-intensity magnetic field (Comparative Example 28).

[0155] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preserving agricultural products after harvest, characterized in that: The method comprises the following steps: precooling the agricultural products and treating them with ozone during the precooling; and then storing the ozone-treated agricultural products in a magnetic field combined with controlled atmosphere.

2. The method for preserving agricultural products after harvest according to claim 1, characterized in that: The precooling temperature is 0.5-4.5° C., and the precooling time is 8-16 hours.

3. The method for preserving agricultural products after harvest according to claim 1, wherein: The ozone treatment method includes: during the pre-cooling period, continuously using ozone shock for 3-6 minutes every 25-35 minutes.

4. The method for preserving agricultural products after harvest according to claim 1 or 3, characterized in that: The concentration of the ozone is 0.3-3.5 μL / L.

5. The method for preserving agricultural products after harvest according to claim 1, wherein: The magnetic field combined with controlled atmosphere storage treatment method includes: transferring the ozone-treated agricultural products into a magnetic field turnover basket and then performing controlled atmosphere storage.

6. The method for preserving agricultural products after harvest according to claim 1 or 5, characterized in that: The intensity of the magnetic field is 1-7 mT.

7. The method for preserving agricultural products after harvest according to claim 1 or 5, characterized in that: The parameters of the controlled atmosphere storage include: O2 volume content of 1-8%, CO2 volume content of 3-18%, N2 volume content of 75-94%, temperature of 0-5°C and humidity of 85-98%.

8. The method for preserving agricultural products after harvest according to claim 1, wherein: The agricultural products include vegetables and fruits.

9. The method for preserving agricultural products after harvest according to claim 8, characterized in that: The vegetables include tomatoes, shiitake mushrooms, and red-stemmed bamboo fungus; the fruits include honey plums, kiwis, blueberries, and apples.

10. Use of the method for preserving agricultural products after harvest according to any one of claims 1 to 9 in extending the storage time of agricultural products and improving the quality of agricultural products.

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