Fresh-keeping method of fresh corn and fresh corn

Abstract

The invention provides a fresh-keeping method of fresh corn and the fresh corn. The fresh-keeping method comprises the following steps: S1, a pretreatment step: pretreating the fresh corn with hydrogen-rich water to obtain pretreated fresh corn; s2, a packaging step: placing at least a part of the pretreated fresh corn in a packaging body; and S3, a storage step: storing the packaging body in which the fresh corn is packaged. The fresh-keeping method disclosed by the invention can inhibit the respiration intensity of the fresh corn, improve the oxidation resistance, improve the storage quality of the harvested fresh corn and prolong the shelf life.

Description

Technical Field

[0001] This invention belongs to the field of preservation technology, specifically relating to a method for preserving fresh corn and the preserved fresh corn prepared using this method, particularly a method for preserving fresh corn using hydrogen-rich water synergistic microporous modified atmosphere packaging technology and its application. Background Technology

[0002] Fresh corn has a unique flavor and is rich in nutrients, including protein, fat, vitamins, essential amino acids, and sugars. It is a low-fat, high-fiber food with high economic, nutritional, and processing value. However, after harvesting, fresh corn undergoes rapid sugar conversion, vigorous respiration, and high water content, making it prone to dehydration and rancidity. This affects its flavor and texture, resulting in a short shelf life and hindering its distribution to some extent.

[0003] Existing fresh corn preservation technologies suffer from several limitations: single preservation techniques have limitations in terms of control; some treatments, such as heat treatment, reduce taste and nutritional value; and preservatives are prone to residues and toxic side effects, failing to effectively address the specific problems in fresh corn preservation. Therefore, to improve the post-harvest quality of fresh corn and extend its storage period, researching and developing efficient, green, and safe new preservation technologies has become an urgent issue.

[0004] Therefore, the present invention aims to develop a new green and efficient technology for preserving fresh corn. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides a method for preserving fresh corn using hydrogen-rich water synergistic microporous modified atmosphere packaging technology, which can inhibit the respiration intensity of fresh corn and improve its antioxidant capacity, thereby improving the storage quality of post-harvest fresh corn and extending its shelf life.

[0006] Specifically, the present invention adopts the following technical solution:

[0007] 1. A method for preserving fresh corn, comprising the following steps:

[0008] S1 - Pretreatment step: The fresh corn is pretreated with hydrogen-rich water to obtain pretreated fresh corn, wherein the hydrogen-rich water contains hydrogen at a concentration of 0.5 ppm to 5 ppm.

[0009] S2 - Packaging Step: At least a portion of the pretreated fresh corn is placed in a packaging body, wherein the packaging body has at least one pore with a pore size of 100-500 μm; and;

[0010] S3 - Storage Step: Store the package containing the fresh corn.

[0011] Optionally, the hydrogen-rich water is prepared using a bubble hydrogen water machine before step S1.

[0012] Optionally, step S1 includes soaking the fresh corn in the hydrogen-rich water for 1-3 hours, and changing the hydrogen-rich water every 0.5-1 hour.

[0013] Optionally, the packaging body is a modified atmosphere box with dimensions of (100-133mm) × (200-224mm) × (50-55mm), and is sealed with a composite film, wherein the oxygen permeability (ORT) of the composite film is less than 10 cm³. 3 / (square meters·day·bar).

[0014] Optionally, the pores are disposed in the composite membrane, the number of pores is 2-5, and the pore diameter is 240-300μm.

[0015] Optionally, the composite film has an encapsulation area of ​​100-300 square centimeters and a thickness of 10-60 μm.

[0016] Optionally, the composite film is polyethylene terephthalate / polyamide resin / ethylene-vinyl alcohol copolymer / polyethylene (PET / PA / EVOH / PE).

[0017] Optionally, step S3 includes storage at a temperature of 0-5°C and a humidity of 90-95%.

[0018] Optionally, the fresh corn is selected from at least one of sweet corn, fresh waxy corn, sweet-waxy corn and baby corn.

[0019] 2. A type of preserved fresh corn, wherein the preserved fresh corn is obtained by any one of the preservation methods described above.

[0020] The present invention has at least one or all of the following beneficial effects:

[0021] (1) This invention combines hydrogen-rich water treatment with microporous modified atmosphere packaging, which can reduce the respiration rate and change the gas environment inside the packaging, thereby reducing the consumption of nutrients by respiration, improving the ability of fresh corn to remove reactive oxygen species, inhibiting membrane lipid peroxidation, reducing the accumulation of malondialdehyde, enhancing the antioxidant level, delaying the ripening and aging of fresh corn, and effectively maintaining the fresh quality of fresh corn.

[0022] (2) Single hydrogen-rich water technology has limitations such as the easy volatilization of hydrogen and the weakening of the preservation effect over time. By using hydrogen-rich water treatment and microporous modified atmosphere packaging in combination, hydrogen-rich water can inhibit initial oxidation, while microporous modified atmosphere packaging can maintain a suitable gas environment inside the packaging, delaying the respiration rate and aging of fresh corn, thereby making up for the shortcomings of single technology and achieving a longer-lasting preservation effect.

[0023] (3) The present invention sequentially pretreats fresh corn with hydrogen-rich water and then treats it with microporous modified atmosphere packaging, which can effectively maintain the freshness of fresh corn and slow down its weight loss, decrease in soluble solids content, decrease in ascorbic acid, and decrease in soluble protein. For example, after refrigeration at 4°C for 14 days, the weight loss rate of fresh corn is 0.80-1.20%, the soluble solids content is 10.00% to 12.00%, the soluble protein content is 2.60% to 2.80%, the malondialdehyde content is 16.00 to 18.00 nmol / g, the relative conductivity is 37.00% to 39.00%, and the ascorbic acid content is 6.00 to 6.50 mg / 100g. Brief description of the attached figures

[0024] Figure 1 A photograph shows fresh corn preserved using the hydrogen-rich water-synergistic microporous modified atmosphere packaging technology of the present invention when a single ear of fresh corn is cut into two pieces.

[0025] Figure 2 Photographs of fresh corn obtained in Example 1 and Comparative Examples 1-3 during storage are shown. Detailed Implementation

[0026] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0028] Conversely, this invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the invention as defined in the claims. Furthermore, to provide a better understanding of the invention, certain specific details are described in detail below. However, those skilled in the art will fully understand the invention even without these detailed descriptions.

[0029] In this article, fresh sweet corn refers to corn ears harvested at the milk stage. The Chinese agricultural industry standard NY / T-523 (Special Grain Corn and Fresh Sweet Corn) is used as the definition standard for fresh sweet corn. Specifically, within the suitable harvest period, the quality standard (the sum of appearance and cooking quality scores within 6 hours) of the corn ear quality test samples must not be lower than the minimum standard of NY / T-523. According to the Chinese agricultural industry standard NY / T-523, fresh sweet corn includes four types: sweet corn, fresh waxy corn, sweet-waxy corn, and baby corn.

[0030] Specifically, sweet corn refers to sweet corn with a soluble sugar content ≥6.0% in the kernels during the appropriate harvest period, also known as fruit corn; fresh waxy corn refers to fresh waxy corn ears during the appropriate harvest period, with only waxy kernels on the same ear, and the amylose content in the dry kernel starch not exceeding 5.00%; sweet-waxy corn refers to fresh waxy corn ears during the appropriate harvest period, with both sweet and waxy kernels, mainly waxy, on the same ear, and the amylose content in the dry kernel starch not exceeding 10.00%; bamboo shoot corn refers to a type of corn whose edible part is the tender young corn ear (harvested before or after the corn silking, unpollenized, resembling a bamboo shoot).

[0031] In recent years, research has found that hydrogen, as a signaling molecule, can participate in plant defense responses to various abiotic stresses. Due to the flammability and explosiveness of hydrogen, it is usually dissolved in pure water to create hydrogen-rich water, which is more convenient and safer than hydrogen gas in practical applications and is commonly used for post-harvest treatment of fruits and vegetables. Hydrogen-rich water is an emerging preservation technology applied to fruit and vegetable preservation in recent years. It can effectively inhibit the activity of browning-related enzymes and enzymes related to the defense against reactive oxygen species (ROS) toxicity in fruit and vegetable tissues, thereby promoting their activity, enhancing their resistance to ROS toxicity and antioxidant capacity, and delaying the onset of aging.

[0032] Modified atmosphere packaging (MAP) works by altering the composition and content of gases within the packaging of fruits and vegetables to inhibit their respiration, thereby reducing nutrient loss and extending shelf life. It is categorized into active MAP, passive MAP, and microporous MAP. MAP technology has no side effects on humans, ensuring the production of pollution-free, green food and maximizing the preservation of fruit and vegetable quality. Microporous MAP is a safe, efficient, and inexpensive passive MAP method. Compared to traditional MAP, microporous membrane MAP overcomes the limitations of high-barrier commercial films by precisely controlling the number and size of micropores. It utilizes the interaction between micropores and the respiration rate of fruits and vegetables to dynamically adjust the concentration of oxygen and carbon dioxide within the packaging in real time, effectively inhibiting respiration and significantly slowing down the aging process. Studies have shown that microporous MAP can effectively inhibit the softening, nutrient loss, and flavor changes in fresh-cut jackfruit during storage, improving its overall quality and extending its shelf life.

[0033] Unexpectedly, the inventors discovered a synergistic effect between hydrogen-rich water and a specific microporous modified atmosphere packaging technology in preserving fresh sweet corn. This significantly inhibits the respiration rate of fresh sweet corn and enhances its antioxidant capacity, thereby improving the storage quality of post-harvest sweet corn and extending its shelf life. In particular, after fresh sweet corn preserved using the method of this invention was refrigerated at 4°C for 14 days, the weight loss rate was 0.80-1.20%, the soluble solids content was 10.00% to 12.00%, the soluble protein content was 2.60% to 2.80%, the malondialdehyde content was 16.00 to 18.00 nmol / g, the relative conductivity was 37.00% to 39.00%, and the ascorbic acid content was 6.00 to 6.50 mg / 100g.

[0034] In one aspect, the present invention provides a method for preserving fresh corn, comprising the following steps:

[0035] S1 - Pretreatment step: The fresh corn is pretreated with hydrogen-rich water to obtain pretreated fresh corn, wherein the hydrogen-rich water contains hydrogen at a concentration of 0.5 ppm to 5 ppm.

[0036] S2 - Packaging Step: At least a portion of the pretreated fresh corn is placed in a packaging body, wherein the packaging body has at least one pore with a pore size of 100-500 μm; and;

[0037] S3 - Storage Step: Store the package containing the fresh corn.

[0038] Prior to step S1, the hydrogen-rich water can be prepared using a bubble hydrogen water machine. The hydrogen-rich water contains hydrogen at a concentration of 0.5 ppm to 5 ppm and distilled water. Preferably, the hydrogen-rich water contains hydrogen at a concentration of 1.6 ppm to 1.9 ppm.

[0039] Optionally, step S1 includes soaking the fresh corn in the hydrogen-rich water for at least 1 hour, preferably at least 3 hours. Preferably, the method of the present invention pre-treats the fresh corn with hydrogen-rich water at a concentration of 1.6-1.9 ppm for 3 hours. The present invention enhances the resistance and antioxidant capacity of fresh corn to reactive oxygen species through hydrogen-rich water pre-treatment, thereby delaying the onset of aging.

[0040] In step S2, at least a portion of the pretreated fresh corn is placed in a packaging body. The at least a portion of the fresh corn may include at least a part of a single ear of corn, or a part of multiple ears of corn, or even a whole ear of corn or multiple ears of corn, preferably a whole ear of corn. Figure 1 The image shows a photograph of fresh corn obtained by using the above-mentioned preservation method when a single ear of fresh corn is cut into two pieces.

[0041] The packaging body has at least one pore with a diameter of 100-500 μm, preferably 250-350 μm. The packaging body can be a microporous modified atmosphere box with dimensions of (100-133 mm) × (200-224 mm) × (50-55 mm).

[0042] Preferably, the pores are disposed in the composite membrane, the number of pores is 2-5, and the pore diameter is 250-350μm.

[0043] Preferably, the composite film has an encapsulation area of ​​100-300 cubic centimeters and a thickness of 10-60 μm.

[0044] Specifically, this invention encapsulates pre-cooled fresh corn using a microporous modified atmosphere packaging material. The modified atmosphere packaging material box is a polypropylene (PP) modified atmosphere box with dimensions of 133cm × 244cm × 55cm, sealed with a PET / PA / EVOH / PE multilayer composite film. The oxygen permeability (ORT) of this composite film is less than 10 cm³. 3 / (square meters·day·bar), the film packaging area is 205cm² 2 The thickness is 40μm. Holes with a diameter of 300μm are punched in the packaging film, with the number of holes set to 2, 3, and 4 respectively.

[0045] According to one embodiment, step S3 includes storing the packaged fresh corn at a temperature of 5°C or lower and a humidity of 90-95%.

[0046] In a second aspect, the present invention provides a preserved fresh corn, which is obtained by any of the preservation methods described above.

[0047] After being refrigerated at 4°C for 14 days, the weight loss of the preserved fresh corn was 1.30-1.60%, the soluble solids content was 9.00% to 11.00%, the soluble protein content was 2.60% to 2.80%, the malondialdehyde content was 16.00 to 18.00 nmol / g, the relative conductivity was 37.00% to 39.00%, and the ascorbic acid content was 6.00 to 6.50 mg / 100g.

[0048] In summary, this invention utilizes hydrogen-rich water pretreatment and microporous modified atmosphere packaging to effectively maintain the freshness of sweet corn, slowing down weight loss, decrease in soluble solids content, decrease in ascorbic acid, and decrease in soluble protein. This invention combines hydrogen-rich water treatment with microporous modified atmosphere packaging to reduce the respiration rate and alter the gaseous environment within the packaging, thereby reducing the consumption of nutrients by respiration, enhancing the sweet corn's ability to scavenge reactive oxygen species, inhibiting membrane lipid peroxidation, reducing malondialdehyde accumulation, enhancing antioxidant levels, delaying the ripening and senescence of sweet corn, and effectively maintaining its fresh quality.

[0049] This invention also provides a method for preserving fresh sweet corn and its application in the transportation and management of sweet corn. This invention combines hydrogen-rich water treatment with microporous modified atmosphere packaging to reduce the respiration rate, effectively delaying the ripening and senescence of post-harvest sweet corn and maintaining its freshness.

[0050] The invention will be further described in detail below with examples.

[0051] Example 1

[0052] A method for preserving fresh corn using hydrogen-rich water-assisted microporous modified atmosphere packaging includes:

[0053] One fresh ear of corn is provided, cut into three sections (Origin: Inner Mongolia; Variety: SBS903 sweet corn).

[0054] The three sections of fresh corn obtained above were soaked in hydrogen-rich water with a hydrogen concentration of 1.8 ppm for 3 hours;

[0055] Three sections of soaked fresh corn were placed in a modified atmosphere packaging (MAP) box measuring 133cm × 244cm × 55cm. The MAP box was sealed with a multi-layer composite film of PET / PA / EVOH / PE, with an oxygen permeability (ORT) of less than 10cm³. 3 / (square meters·day·bar), the film packaging area is 205cm² 2 The thickness is 44μm. To regulate the gas composition inside the packaging box, perforations are made in the packaging film with a pore size of 250-350μm and a pore count of 2. The modified atmosphere box is stored in an environment with a temperature of 4℃ and a humidity of 95%, denoted as HRW-MMAP2.

[0056] Example 2

[0057] A method for preserving fresh corn using hydrogen-rich water-assisted microporous modified atmosphere packaging includes:

[0058] One fresh corn cob is provided, cut into three sections (origin: Inner Mongolia, variety: SBS903 sweet corn);

[0059] The three sections of fresh corn obtained above were soaked in hydrogen-rich water with a hydrogen concentration of 1.8 ppm for 3 hours;

[0060] Three sections of soaked fresh corn were placed in a modified atmosphere packaging (MAP) box measuring 133cm × 244cm × 55cm. The MAP box was sealed with a multi-layer composite film of PET / PA / EVOH / PE, with an oxygen permeability (ORT) of less than 10cm³. 3 / (square meters·day·bar), the film packaging area is 205cm² 2 The thickness is 40μm. To regulate the gas composition inside the packaging box, perforations are made in the packaging film with a pore size of 250-350μm and a pore count of 3. The modified atmosphere box is stored in an environment with a temperature of 4℃ and a humidity of 95%, denoted as HRW-MMAP3.

[0061] Example 3

[0062] A method for preserving fresh corn using hydrogen-rich water-assisted microporous modified atmosphere packaging includes:

[0063] One fresh corn cob is provided, cut into three sections (Origin: Inner Mongolia, Variety: SBS903 sweet corn);

[0064] The two pieces of fresh corn obtained above were soaked in hydrogen-rich water with a hydrogen concentration of 1.8 ppm for 3 hours;

[0065] Two sections of soaked fresh corn were placed in a modified atmosphere packaging (MAP) box measuring 133cm × 244cm × 55cm. The MAP box was sealed with a multi-layer composite film of PET / PA / EVOH / PE, with an oxygen permeability (ORT) of less than 10cm³. 3 / (square meters·day·bar), the film packaging area is 205cm² 2 The thickness is 40μm. To regulate the gas composition inside the packaging box, perforations are made in the packaging film with a pore size of 250-350μm and a pore count of 4. The modified atmosphere box is stored in an environment with a temperature of 4℃ and a humidity of 95%, denoted as HRW-MMAP4.

[0066] Comparative Example 1

[0067] One method for preserving fresh corn includes:

[0068] Fresh corn was cut into three sections as in Example 1 and stored at 4°C (origin: Inner Mongolia, variety: SBS903 sweet corn). This section was designated CK.

[0069] Comparative Example 2

[0070] One method for preserving fresh corn includes:

[0071] Fresh corn was cut into three sections as in Example 1, and the sections (origin: Inner Mongolia, variety: SBS903 sweet corn) were soaked in hydrogen-rich water with a hydrogen concentration of 1.8 ppm for 3 hours and stored at 4°C. This was denoted as HRW.

[0072] Comparative Example 3

[0073] One method for preserving fresh corn includes:

[0074] Cut the fresh corn into three sections as described in Example 1, and place the fresh corn (origin: Inner Mongolia, variety: SBS903 sweet corn) into a modified atmosphere packaging (MAP) box measuring 133cm × 244cm × 55cm. The MAP box is sealed with a PET / PA / EVOH / PE multilayer composite film, with an oxygen permeability (ORT) of less than 10cm³. 3 / (square meters·day·bar)), the film packaging area is 205cm² 2 The thickness is 40 μm. To regulate the gas composition inside the packaging box, perforations are made in the packaging film with a pore size of 250-350 μm and a pore number of 4. The modified atmosphere box is stored in an environment with a temperature of 4°C and a humidity of 95%, denoted as MMAP.

[0075] Experimental Example 1

[0076] The following measurements were taken from fresh corn in Examples 1-3 and Comparative Examples 1-3:

[0077] 1. Take photos to record

[0078] Fresh sweet corn from Examples 1-3 and Comparative Examples 1-3 were photographed and recorded on storage days 0, 2, 4, 6, 8, 10, 12, and 14. The results are as follows: Figure 2 As shown.

[0079] Depend on Figure 2 It can be seen that the fresh corn in group CK first showed signs of dehydration and shrinkage, and by the 8th day of storage, the fresh corn had severely shrunk and lost its commercial value. The fresh corn in group HRW first shrunk by the 10th day of storage. However, the fresh corn in groups MMAP and HRW-MMAP2 (Example 1) 4 did not show signs of shrinkage during storage, indicating that the hydrogen-rich water pretreatment combined with microporous modified atmosphere packaging technology of the present invention better maintains the appearance quality of fresh corn.

[0080] 2. Calculation of weight loss rate (%)

[0081] Using a laboratory electronic analytical balance with an accuracy of 0.01g, fresh corn stored on days 0, 2, 4, 6, 8, 10, 12, and 14 was weighed separately and recorded as W1. The initial weight was recorded as W0. The weight loss rate was calculated, and the results are shown in Table 1.

[0082] Table 1. Weight loss rate (%) of fresh corn under different treatment methods. Table 1. Weight loss rate (%) of fresh corn during storage.

[0083]

[0084] The results showed that the weight loss rate continued to increase with storage time. The weight loss rates of the HRW-MMAP2, MMAP3 and HRW-MMAP4 groups increased steadily during storage, which was significantly lower than that of CK and HRW. The hydrogen-rich water synergistic microporous modified atmosphere packaging treatment method of the present invention significantly inhibited the loss of moisture in fresh corn and slowed down the weight loss.

[0085] 3. Determination of soluble solids content

[0086] On storage days 0, 2, 4, 6, 8, 10, 12, and 14, corn kernels from each group were homogenized, centrifuged, and the supernatant was collected. The soluble solids content of fresh corn under different storage times was determined using a handheld saccharimeter.

[0087] Table 3. Soluble solids (TSS) content (%) of fresh corn under different treatments. Table 3. Soluble solids values ​​of fresh corn during storage.

[0088]

[0089]

[0090] The TSS of the CK group decreased continuously from 14.33 to 9.33, while the TSS of the co-treatment group decreased steadily and remained stable in the later stage of storage. The TSS of HRW-MMAP2, MMAP3, and HRW-MMAP4 were all higher than those of the CK, HRW, and MMAP groups used as comparisons at 14 days, indicating that under these conditions, HRW-MMAP2, MMAP3, and HRW-MMAP4 effectively maintained the sugar content of fresh corn and delayed quality deterioration.

[0091] 4. pH measurement

[0092] On storage days 0, 2, 4, 6, 8, 10, 12, and 14, corn kernels from each group were homogenized, centrifuged, and the supernatant was collected. The pH value of fresh corn at different storage times was measured using a pH meter.

[0093] Table 4 pH values ​​of fresh corn during storage

[0094]

[0095] As shown in Table 4, the pH decreased with prolonged storage time. The pH in the CK group decreased continuously from 6.71 to 6.35, and the pH in the HRW group decreased to 6.38. However, the pH decrease was smaller in the synergistic groups HRW-MMAP2, MMAP3, and HRW-MMAP4. HRW-MMAP2 had the most significant effect on delaying the pH decrease, reaching 6.49 on day 14. Under these conditions, the metabolic activity of microorganisms and the accumulation of organic acids may have been inhibited.

[0096] 5. Determination of soluble protein content

[0097] On storage days 0, 2, 4, 6, 8, 10, 12, and 14, 0.1 g of fresh corn was taken and the soluble protein content of the fresh corn was determined using a soluble protein content detection kit.

[0098] Table 5. Soluble protein content (mg / mL) of fresh corn under different treatments

[0099]

[0100]

[0101] The soluble protein content in the CK group decreased from 3.36 mg / mL to 2.29 mg / mL, indicating significant degradation. The soluble protein content in HRW-MMAP2, HRW-MMAP3, and HRW-MMAP4 groups was higher than that in the other control groups during storage, suggesting that this treatment slowed down protein decomposition. This indirectly indicates a reduction in oxidative damage, maintenance of cell membrane integrity, retention of soluble proteins, and prevention of nutrient loss.

[0102] Experimental Example 2

[0103] 6. Calculation of malondialdehyde content

[0104] On storage days 0, 2, 4, 6, 8, 10, 12, and 14, 0.1 g of fresh corn was taken and the malondialdehyde (MDA) content of the fresh corn was detected using a malondialdehyde (MDA) content detection kit.

[0105] Table 6. Malondialdehyde content (nmol / g) of fresh corn under different treatments

[0106]

[0107] The MDA level in the CK group increased from 7.69 nmol / g to 23.18 nmol / g, indicating severe oxidative damage. The MDA value of HRW-MMAP2 at 14 days was 17.12 nmol / g, lower than other comparative groups. Similarly, the MDA values ​​of HRW-MMAP3 and HRW-MMAP4 at 14 days were 17.24 nmol / g and 17.29 nmol / g, respectively, also lower than other comparative groups. This suggests that the synergistic effect of hydrogen-rich water and modified atmosphere packaging significantly inhibited lipid oxidation and MDA accumulation, reducing cellular oxidative damage, consistent with the results obtained from relative conductivity.

[0108] 7. Calculation of relative conductivity (%)

[0109] On storage days 0, 2, 4, 6, 8, 10, 12, and 14, 20 kernels of fresh corn were taken respectively, added to 100 mL of deionized water, and allowed to stand at room temperature for 24 hours. The conductivity C1 was measured, followed by a 20-minute boiling water bath and cooling. The conductivity C2 was then measured. The relative conductivity was calculated as: Relative conductivity (%) = C1 / C2 × 100%.

[0110] Table 7. Relative electrical conductivity (%) of fresh corn under different treatments

[0111]

[0112] As time progressed, the relative conductivity of each group showed an increasing trend. The relative conductivity of the HRW-MMAP2, HRW-MMAP3, and HRW-MMAP4 groups increased the slowest, indicating that the treatment significantly inhibited the increase in conductivity, effectively maintained the integrity of the cell membrane, reduced cell damage, and thus helped maintain the high freshness and quality of fresh corn.

[0113] 8. Ascorbic acid calculation

[0114] The ascorbic acid content of fresh corn was determined by 2,6-dichlorophenolindophenol titration at storage days 0, 2, 4, 6, 8, 10, 12, and 14.

[0115] Table 8. Ascorbic acid content (mg / 100g) of fresh corn under different treatments

[0116]

[0117] During storage, the vitamin C content in the CK group decreased from 8.29 mg / 100g to 5.53 mg / 100g, indicating severe oxidative loss and nutrient depletion. The HRW-MMAP2, HRW-MMAP3, and HRW-MMAP4 groups also showed significant nutrient loss.

[0118] The vitamin C levels were higher than in other groups, and the decrease was relatively small, indicating that the synergistic treatment slowed down the loss of vitamin C and enhanced its stability.

[0119] 9. Calculation of Synergy Index

[0120] To evaluate the enhancing effect of the combined treatment (HRW-MMAP2) on the indicators (soluble protein, malondialdehyde, ascorbic acid), the "synergy index" was used to measure its effect relative to the single treatment.

[0121] Theoretical value T A =T HRW +T MMAP -T CK

[0122] Actual value T B =T HRW-MMAP

[0123] Synergy index T = T A / T B

[0124] Table 9 Synergy Index of Example 1

[0125]

[0126] Soluble protein and ascorbic acid are nutritional indicators during the storage of fresh corn. These values ​​decrease over time, with lower values ​​indicating more severe quality deterioration. After synergistic treatment, the synergistic indices T1 and T3 were both less than 1 after the 6th day of storage and beyond, indicating that the synergistic treatment with hydrogen-rich water and microporous modified atmosphere delayed the loss of soluble protein and ascorbic acid in fresh corn. Malondialdehyde (MDA) reflects the degree of oxidation during the storage of fresh corn. This value increases over time, with higher values ​​indicating more severe quality deterioration. After synergistic treatment, the synergistic index T2 was greater than 1 after the 2nd day, indicating that the synergistic treatment with hydrogen-rich water and microporous modified atmosphere reduced the degree of oxidation in fresh corn over time. Therefore, the effect of synergistic treatment with hydrogen-rich water and microporous modified atmosphere is superior to the single or combined effects of hydrogen-rich water or microporous modified atmosphere treatment alone.

[0127] In summary, the hydrogen-rich water and microporous modified atmosphere packaging technology of the present invention can effectively reduce the respiration rate of fresh corn, regulate the gas environment inside the packaging, thereby reducing the consumption of nutrients by respiration, delaying the increase in weight loss, enhancing antioxidant capacity, slowing down the consumption of soluble solids, reducing the degree of peroxidation of cell membrane lipids and electrolyte permeation, maintaining the structural stability of cell membranes, and reducing the accumulation of malondialdehyde.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preserving fresh corn, characterized in that... Includes the following steps: S1 - Pretreatment step: The fresh corn is pretreated with hydrogen-rich water to obtain pretreated fresh corn, wherein the hydrogen-rich water contains hydrogen at a concentration of 0.5 ppm to 5 ppm. S2 - Packaging Step: At least a portion of the pretreated fresh corn is placed in a packaging body, wherein the packaging body has at least one pore with a pore size of 100-500 μm; and; S3 - Storage Step: Store the package containing the fresh corn.

2. The preservation method according to claim 1, characterized in that... The hydrogen-rich water is prepared using a bubble hydrogen water machine before step S1.

3. The preservation method according to claim 1 or 2, characterized in that, Step S1 includes soaking the fresh corn in the hydrogen-rich water for 1-3 hours, and changing the hydrogen-rich water every 0.5-1 hour.

4. The preservation method according to claim 1, characterized in that... The packaging body is a modified atmosphere box with dimensions of (100-133mm) × (200-224mm) × (50-55mm), and is sealed with a composite film, wherein the oxygen permeability (ORT) of the composite film is less than 10 cm³. 3 / (square meters·day·bar).

5. The preservation method according to claim 4, characterized in that... The pores are arranged in the composite membrane, with 2-5 pores and a pore diameter of 240-300 μm.

6. The preservation method according to claim 4, characterized in that... The composite film has an encapsulation area of ​​100-300 square centimeters and a thickness of 10-60 μm.

7. The preservation method according to claim 4, characterized in that... The composite membrane is polyethylene terephthalate / polyamide resin / ethylene-vinyl alcohol copolymer / polyethylene.

8. The preservation method according to claim 1, characterized in that... Step S3 includes storing for at least 6 days at a temperature of 0-5°C and a humidity of 90-95%.

9. The preservation method according to claim 1, characterized in that... The fresh corn is selected from at least one of sweet corn, fresh glutinous corn, sweet and glutinous corn and baby corn.

10. A method for preserving fresh corn, characterized in that... The preserved fresh corn is obtained by the preservation method described in any one of claims 1 to 9.

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