Quick-freezing and freshness-locking process for mango blocks

Abstract

The invention discloses a quick-freezing fresh-keeping process for mango blocks, and belongs to the technical field of fruit and vegetable processing and freezing fresh-keeping, the mango blocks are soaked in a compound solution containing fucoidin and mannitol at low temperature, a'synbiotics fresh-keeping layer 'with physical barrier and prebiotics functions is constructed, and then pre-cooling, quick freezing and low-temperature high-humidity storage are combined, so that the fresh-keeping effect of the mango blocks is improved. The growth of ice crystals is effectively inhibited and cell damage is reduced. According to the technology, the juice loss rate after unfreezing is remarkably reduced, the hardness retention rate reaches 82.3%-88.1%, the color and luster are stable (delta E is smaller than or equal to 3.2), the sensory score exceeds 92, the technology is obviously superior to a traditional quick-freezing method, the quality of the mango blocks in the freezing process is efficiently kept, and a new path is provided for high-valued freezing preservation of tropical fruits.

Description

Technical Field

[0001] This invention belongs to the field of fruit and vegetable processing and freezing preservation technology, and particularly relates to a quick-freezing and fresh-locking process for mango chunks. Background Technology

[0002] mango( Mangifera indica L. Mango, a typical tropical cash crop, is known as the "King of Tropical Fruits" due to its unique flavor and rich nutritional components, and has become an important fruit category in global trade. Its fruit is rich in vitamins, phenolic compounds, and secondary metabolites, possessing both nutritional and health benefits, and is widely used in fresh consumption, frozen fruit, and processed products. With the rapid growth of global mango planting area and yield, and the improvement of cold chain logistics systems, quick-frozen mango chunks are gradually becoming a popular product in the fruit and vegetable processing industry due to their ease of storage, transportation, and subsequent processing such as making juice, jam, desserts, and baking ingredients, with market demand continuing to rise.

[0003] However, the inherent physiological characteristics of mangoes and the limitations of existing processing techniques present numerous challenges to improving the quality of quick-frozen mango chunks. Mangoes are climacteric fruits, exhibiting active post-harvest metabolism. Ethylene-induced ripening easily leads to fruit softening, color deterioration, and pathogen infection, typically limiting their post-harvest lifespan to no more than three weeks. To extend this lifespan, mangoes are often stored in low-temperature environments; however, storage temperatures below 13°C can cause chilling injury, resulting in browning of the flesh, pitting of the skin, and loss of flavor. Furthermore, mango flesh has a loose tissue structure with large intercellular spaces, a high water content (80%-90%), and relatively low cell wall mechanical strength, making it highly susceptible to physical and chemical influences during post-harvest handling and processing.

[0004] Especially during freezing and thawing, if the freezing rate is not properly controlled, large needle-like ice crystals can easily form inside the mango pieces. These ice crystals, as they grow, continuously compress and pierce cell walls and cell membranes, damaging cell integrity. During thawing, the damaged cells cannot effectively retain moisture and nutrients, leading to a significant loss of juice. This not only results in the loss of nutrients such as soluble sugars, organic acids, and flavor compounds, but also causes the mango pieces to soften, collapse, and become dry, severely impacting product quality. Furthermore, mangoes are rich in polyphenols, and enzymes such as polyphenol oxidase and peroxidase have high activity. During processing and storage, if the cell structure is damaged, the enzymes will come into full contact with their substrates, triggering an enzymatic browning reaction. This causes brown spots or overall browning on the surface of the mango pieces, reducing their appearance and decreasing consumer willingness to purchase.

[0005] Existing mango quick-freezing processing technologies have the following main shortcomings: First, most processes only focus on simple color protection before quick-freezing, such as using single color-protecting agents like sulfites or citric acid, or antioxidant treatments. They do not pay enough attention to the cell structure damage and water migration caused by ice crystal growth during freezing, making it difficult to achieve a comprehensive effect of color preservation, textural stability, and flavor retention. Second, the process parameters lack specificity and do not fully consider the characteristics of different mango varieties. There are many mango varieties, and different varieties have significant differences in tissue structure, sugar content, cell osmotic pressure, and enzyme activity, resulting in large fluctuations in product quality and poor adaptability during production. Third, some processes are complex to operate, have high costs, or use additives that do not meet the needs of healthy consumption, which limits their industrial application.

[0006] Therefore, there is an urgent need for a quick-freezing process that can effectively regulate the tissue state of mango chunks before quick-freezing and reduce ice crystal damage during freezing, thereby improving the quality stability after thawing. In particular, developing a novel coating technology that combines cell structure protection, flavor retention, and potential probiotic functions, incorporating modern nutritional concepts, is of great significance for enhancing the added value and market competitiveness of quick-frozen mango chunks and creating high-quality fresh-locking fruit chunk substrate products. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a quick-freezing and freshness-preserving process for mango chunks.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A quick-freezing process for mango chunks to lock in freshness includes the following steps: Fresh mango chunks are soaked in a pretreatment solution containing fucoidan and mannitol to stabilize cell structure, inhibit ice crystal growth, and reduce freeze-thaw damage. After draining, they are pre-cooled and then rapidly frozen to ensure the formation of small and uniform ice crystals. Finally, they are frozen for storage, which effectively preserves the texture, color, flavor, and nutritional quality of the mango chunks.

[0009] Optionally, the fresh mango chunks are selected from Guifei mango, Tainong mango, or Jinhuang mango.

[0010] Optionally, the mass concentration of fucoidan in the pretreatment solution is 0.1%-0.5%, and the mass concentration of mannitol is 1%-3%.

[0011] Furthermore, the pretreatment solution also includes antioxidants.

[0012] Furthermore, the antioxidant is ascorbic acid.

[0013] Optionally, the immersion conditions are as follows: immersion at a low temperature of 4-8°C for 15-30 minutes, during which the vessel is gently turned over every 5-10 minutes.

[0014] Optionally, the precooling conditions are: precooling at 0-4℃ for 30-60 minutes.

[0015] Optionally, the rapid freezing step involves using a liquid nitrogen freezer, a spiral freezer, or a tunnel freezer to rapidly reduce the center temperature of the mango chunks to below -18°C.

[0016] Furthermore, when using a tunnel-type quick-freezing machine, the evaporation temperature for rapid freezing is -40℃, the wind speed is 4m / s, and the freezing time is 20 minutes.

[0017] Furthermore, when using a spiral quick-freezing machine, the evaporation temperature for rapid freezing is -45℃, the wind speed is 5m / s, and the freezing time is 18min.

[0018] Furthermore, when using a liquid nitrogen quick-freezing machine, the freezing temperature for rapid freezing is -196℃, and the freezing time is 8 minutes.

[0019] Furthermore, during the rapid freezing process, it is ensured that the time for the mango pieces to pass through the maximum ice crystal formation zone does not exceed 30 minutes.

[0020] Optionally, the freezing storage conditions are: freezing storage at -18°C or below and relative humidity of 90%-95%.

[0021] Optionally, the quick-freezing and freshness-locking process for the mango chunks specifically includes the following steps: (1) Raw material processing: Select fresh mangoes with suitable maturity, intact fruit shape, no mechanical damage or pests and diseases, wash and drain them; (2) Peel and cut into pieces: Peel and pit the mango and cut it into pieces of roughly the same size; (3) Pretreatment: Prepare a pretreatment solution containing fucoidan and mannitol, and immerse the mango pieces in the solution for low-temperature soaking treatment; (4) Draining and pre-cooling: Drain the soaked mango pieces and pre-cool them at a low temperature; (5) Rapid freezing treatment: Rapidly freeze the pre-cooled mango pieces until the core temperature is below -18℃; (6) Freezing: Transfer the quick-frozen mango pieces to a low-temperature environment for freezing and storage.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects: (1) This invention effectively reduces the juice loss rate of mango chunks through the synergistic effect of pretreatment with specific synbiotics (fucoidan and mannitol) and quick-freezing; (2) The rapid freezing process defined in this invention forms fine and uniformly distributed ice crystals, which significantly reduces cell structure damage, effectively maintains cell integrity, and makes the intracellular water distribution state closest to that of a fresh sample. (3) The process of the present invention can improve the texture retention rate of mango pieces after thawing, effectively solve the problem of fruit piece collapse, and make it close to the state of fresh mango; (4) The process flow of this invention is clear, the functions are complex, and it is suitable for industrial production. Specifically, this invention organically combines functional coating with quick-freezing technology to form a replicable technical procedure, which provides technical support for creating high-quality, high-value-added specialty fresh-locking fruit block base products.

[0023] Furthermore, to further verify the effect of the process of this invention on improving the frozen quality of mango chunks, a comparative test was conducted on mango chunks treated with the process of this invention and mango chunks that were directly quick-frozen without pretreatment. The test indicators included juice loss rate, firmness retention rate, and color change.

[0024] Test results show that mango pieces treated with the process of this invention have a significantly lower juice loss rate after thawing compared to mango pieces that were directly quick-frozen without pretreatment, with a juice loss rate reduced by approximately 20% to 40%. Simultaneously, the firmness retention rate of the mango pieces is significantly improved, and the texture is more intact after thawing, making them less prone to collapse.

[0025] Furthermore, under the same frozen storage conditions, the mango pieces treated with the process of this invention showed a smaller change in color, indicating that the process mitigated the quality deterioration during freezing and thawing to a certain extent. Detailed Implementation

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0028] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0029] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0030] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0031] This invention discloses a quick-freezing and freshness-locking process for mango chunks, comprising the following steps: (1) Raw material processing Select fresh mangoes that are ripe, intact, and free from mechanical damage and pests. Wash them, remove surface impurities, and drain them to provide a stable raw material base for subsequent processing.

[0032] (2) Peel and cut into pieces Peel and pit the mangoes processed in step (1), and cut them into mango pieces of roughly the same size according to the predetermined specifications to ensure uniformity in subsequent processing and freezing.

[0033] (3) Pretreatment A pretreatment solution is prepared, which is a compound solution of fucoidan and mannitol. The mass concentration of fucoidan is 0.1%-0.5%, the mass concentration of mannitol is 1%-3%, and the solvent is deionized water. During the preparation process, appropriate stirring can be carried out to accelerate dissolution and ensure uniform solution concentration.

[0034] The mango pieces obtained in step (2) are completely immersed in the pretreatment solution for soaking. The soaking temperature is controlled at 4-8℃ and the soaking time is 15-30 minutes. During this period, the mango pieces are gently turned over every 5-10 minutes to ensure that the mango pieces are in full contact with the pretreatment solution so that the pretreatment solution can penetrate evenly into the mango piece tissue. In this coating solution (i.e., pretreatment solution), fucoidan, as a functional component, enhances cell membrane stability and inhibits ice crystal growth; mannitol, as an osmotic regulator, lowers the cell freezing point and reduces low-temperature stress damage. This membrane not only acts as a physical barrier to block oxygen, reduce water migration and flavor efflorescence, but also serves as a prebiotic component, synergistically enhancing the product's nutritional function. The combined effect of these two components constructs a "synbiotic freshness-locking barrier" on the surface and outer tissues of the mango, minimizing cell damage and quality deterioration during subsequent freeze-thaw cycles.

[0035] (4) Draining and pre-cooling Take out the mango pieces after step (3), drain the residual solution on the surface, and pre-cool them at a low temperature of 0-4℃ for 30-60 minutes to lower the overall temperature of the mango pieces and make them more uniform, thereby reducing tissue damage caused by excessive temperature difference during the subsequent quick-freezing process.

[0036] (5) Quick-freezing treatment Pre-cooled mango pieces are placed in a quick-freezing device for rapid freezing, ensuring that the core temperature of the mango pieces drops rapidly to below -18°C. This allows the mango pieces to pass through the maximum ice crystal formation zone (-1°C to -5°C) within 30 minutes, thereby forming a fine and evenly distributed ice crystal structure and avoiding damage to cells from large ice crystals.

[0037] (6) Frozen storage The quick-frozen mango chunks are then transferred to a low-temperature environment for freezing and storage. The storage temperature is controlled below -18℃, and the relative humidity in the storage is maintained at 90%-95% to maintain their frozen state and ensure stable product quality, thus obtaining quick-frozen fresh-locking mango chunk products.

[0038] In some alternative embodiments, the ratio of fucoidan to mannitol in the pretreatment solution in step (3) can be adjusted appropriately according to the mango variety and maturity.

[0039] In some alternative embodiments, the pretreatment in step (3) is carried out under low temperature conditions to reduce the metabolic activity of the mango pieces during the processing.

[0040] In some alternative embodiments, the quick-freezing process in step (5) is an ultra-fast cryogenic freezing method to shorten the freezing time and reduce the ice crystal size.

[0041] All raw materials used in this invention were purchased from the market.

[0042] The technical solution of the present invention will be further illustrated by the following embodiments.

[0043] Example 1 A quick-freezing process for mango chunks to lock in freshness includes the following steps: (1) Select 6 kg of 7-8 ripe Taiwan mangoes. Choose fresh mangoes that are free from mechanical damage, pests and diseases, and have a complete fruit shape. The mangoes should be from Baise, Guangxi. Wash them with running water for 3 minutes and drain off the surface moisture.

[0044] (2) After mechanical peeling and pitting, the flesh is cut into cube mango pieces with a side length of 2-3cm using a vegetable cutter, and the weight difference of a single piece is controlled to not exceed 8%.

[0045] (3) Prepare a pretreatment solution with a fucoidan concentration of 0.3% and a mannitol concentration of 1.5%, and add 0.08% ascorbic acid, and dissolve it evenly with deionized water.

[0046] Immerse the mango pieces from step (2) in the pretreatment solution at a temperature of 4°C for 25 minutes, turning them over every 5 minutes.

[0047] (4) Take out the mango pieces and drain for 8 minutes. Spread them flat on a tray and put them in a pre-cooling room. Pre-cool them at 0℃ for 60 minutes to reduce the center temperature of the mango pieces to 2℃.

[0048] (5) Use a spiral quick-freezing machine, set the evaporation temperature to -45℃, the wind speed to 5m / s, freeze for 18min, and ensure that the center temperature of the mango pieces reaches -20℃.

[0049] (6) After sealing and packaging, transfer to a -18℃ freezer for storage, and maintain the relative humidity in the freezer at 92%.

[0050] The test results show that after thawing, the juice loss rate of mango pieces treated with the process of Example 1 was 7.8%, which is 37.6% lower than that of the traditional process of direct quick-freezing without pretreatment solution (Comparative Example 1); the hardness retention rate was 85.6%, and the texture was close to that of fresh mangoes; the color change ΔE value was 2.9, and browning was effectively suppressed; the sensory score was 93.1 points, and the flavor and taste were excellent.

[0051] The methods for determining the relevant indicators are as follows: Juice loss rate determination method: Weigh the frozen mango pieces, place them on filter paper, and thaw them in a 4℃ freezer. After complete thawing, wipe the surface moisture of the mango pieces with filter paper and weigh them. The calculation formula is as follows: Formula 1; In the formula: WL is the juice loss rate (%); W0 is the mass of the mango piece before thawing (g); W1 is the mass of the filter paper before the test (g); W2 is the mass of the filter paper after the test (g).

[0052] Method for measuring color change: Take 5.00 g of fresh and thawed mango pulp, and use a colorimeter to measure the brightness value L of different mangoes. Red-green value a And the yellow-blue value b Color difference (∆E) is the change between two points, and the calculation formula is as follows: Formula 2; In the formula: ∆E value represents the color difference of the mango before and after freezing; L a b a0 represents the measurement of a fresh mango. b0 L0 These are measurements of the mangoes after they have been thawed.

[0053] Sensory evaluation method: Twelve trained food professionals conducted sensory evaluations of the thawed mango chunks, scoring them on four aspects: appearance, texture, taste, and aroma, with a maximum score of 100. The overall liking score was obtained by summing the evaluations of each evaluator for the same mango chunk across the four aspects and taking the average. The sensory evaluation criteria are shown in Table 1.

[0054] Table 1 Sensory Evaluation Criteria Example 2 A quick-freezing process for mango chunks to lock in freshness includes the following steps: (1) Select 5 kg of fresh Guifei mangoes that are 7-8 ripe, with intact fruit shape, no mechanical damage, and no pests or diseases. The mangoes should be from Baise, Guangxi. Put the mangoes into a washing machine and rinse them with running water to remove surface impurities for 5 minutes. After washing, drain the surface water.

[0055] (2) Peel and pit manually, remove the peel and pit, put the flesh into a vegetable cutter and cut it into cube mango pieces with a side length of 2-3cm to ensure that the pieces are uniform in shape.

[0056] (3) Prepare a pretreatment solution by using deionized water as a solvent, adding fucoidan and mannitol to make the fucoidan mass concentration 0.2% and the mannitol mass concentration 2%, and stirring to dissolve before use.

[0057] The mango pieces from step (2) are completely immersed in the pretreatment solution. The immersion temperature is controlled at 6°C and the immersion time is 20 minutes. During this period, the mango pieces are turned over once every 8 minutes.

[0058] (4) Take out the soaked mango pieces, put them in a draining basket to drain for 10 minutes, then spread them flat on a tray and put them in a pre-cooling room to pre-cool for 45 minutes at 2°C.

[0059] (5) Transfer the pre-cooled mango pieces into a tunnel-type quick-freezing machine, set the evaporation temperature to -40℃, the wind speed to 4m / s, freeze for 20 minutes, and ensure that the center temperature of the mango pieces drops below -18℃.

[0060] (6) Seal the quick-frozen mango pieces in polyethylene film bags and store them in a -18℃ freezer.

[0061] Testing showed that the mango chunks treated using the process in Example 2 had a juice loss rate of 8.5% after thawing, which was 39.4% lower than the traditional process of direct quick-freezing without pretreatment solution (the only difference from Comparative Example 1 was that the mango variety was replaced with the Guifei mango used in Example 2); the hardness retention rate was 82.3%, and the texture was firm and elastic; the color change ΔE value was 3.2, and the appearance was bright and bright with no obvious browning; the sensory score was 92.5 points, and the overall quality was better than the samples processed by the traditional process.

[0062] Example 3 A quick-freezing process for mango chunks to lock in freshness includes the following steps: (1) Select 4 kg of 80% ripe Golden Emperor mangoes. Choose fresh mangoes that are free from rot and damage and originate from Baise, Guangxi. Wash them with running water and food-grade detergent, and drain the water after washing.

[0063] (2) After peeling and pitting by hand, cut the mango into slices with a thickness of 1.5cm to ensure that the slices are of uniform thickness.

[0064] (3) Prepare a pretreatment solution with a fucoidan concentration of 0.4% and a mannitol concentration of 1%, and dissolve them in deionized water for later use.

[0065] Immerse the mango pieces from step (2) in the pretreatment solution at a temperature of 8°C for 15 minutes, turning them over twice during the process.

[0066] (4) After draining for 5 minutes, spread it flat on a tray and place it in a pre-cooling device to pre-cool for 30 minutes at 4°C.

[0067] (5) Use a liquid nitrogen quick-freezing machine with a freezing temperature of -196℃ and a freezing time of 8min to allow the mango pieces to quickly pass through the zone of maximum ice crystal formation.

[0068] (6) After sealing and packaging, transfer to a -18℃ freezer for storage.

[0069] The test results show that, compared with the ordinary quick-freezing method, the mango pieces treated with the process of Example 3 showed a significant reduction in tissue structure damage after thawing, with a juice loss rate of only 6.9%, which is 38.9% lower than the traditional process of direct quick-freezing without pretreatment solution (the only difference from Comparative Example 1 is that the mango variety was replaced with the Golden Mango used in Example 3); the hardness retention rate was 88.1%, and the shape was intact without collapse; the color change ΔE value was 2.7, and the appearance was bright; the overall sensory quality was good, with a sensory score of 94.2 points.

[0070] Comparative Example 1 A traditional method for quick-freezing mangoes includes the following steps: (1) Select 6 kg of 7-8 ripe Taiwan mangoes. Choose fresh mangoes that are free from mechanical damage, pests and diseases, and have a complete fruit shape. The mangoes should be from Baise, Guangxi. Wash them with running water for 3 minutes and drain off the surface moisture.

[0071] (2) After mechanical peeling and pitting, the flesh is cut into cube mango pieces with a side length of 2-3cm using a vegetable cutter, and the weight difference of a single piece is controlled to not exceed 8%.

[0072] (3) After spreading the mango pieces flat on the tray, put them into the pre-cooling room and pre-cool them at 0℃ for 60 minutes to reduce the center temperature of the mango pieces to 2℃.

[0073] (4) Use a spiral quick-freezing machine, set the evaporation temperature to -45℃, the wind speed to 5m / s, freeze for 18min, and ensure that the center temperature of the mango pieces reaches -20℃.

[0074] (5) After sealing and packaging, transfer to a -18℃ freezer for storage, and maintain the relative humidity in the freezer at 92%.

[0075] The test results showed that after thawing, the mango pieces treated with the process of Comparative Example 1 had a juice loss rate of 12.5%; a hardness retention rate of 22.9%, and a soft and mushy texture; a color change ΔE value of 5.6, indicating severe browning; and a sensory score of 65.2, indicating poor flavor and taste.

[0076] Comparative Example 2 A process for quick-freezing and preserving the freshness of mango chunks includes the following steps: (1) Select 6 kg of 7-8 ripe Taiwan mangoes. Choose fresh mangoes that are free from mechanical damage, pests and diseases, and have a complete fruit shape. The mangoes should be from Baise, Guangxi. Wash them with running water for 3 minutes and drain off the surface moisture.

[0077] (2) After mechanical peeling and pitting, the flesh is cut into cube mango pieces with a side length of 2-3cm using a vegetable cutter, and the weight difference of a single piece is controlled to not exceed 8%.

[0078] (3) Prepare a pretreatment solution with CaCl2 mass concentration of 0.1% and ascorbic acid concentration of 0.5%, and dissolve it evenly with deionized water.

[0079] Immerse the mango pieces from step (2) in the pretreatment solution at a temperature of 4°C for 25 minutes, turning them over every 5 minutes.

[0080] (4) Take out the mango pieces and drain for 8 minutes. Spread them flat on a tray and put them in a pre-cooling room. Pre-cool them at 0℃ for 60 minutes to reduce the center temperature of the mango pieces to 2℃.

[0081] (5) Use a spiral quick-freezing machine, set the evaporation temperature to -45℃, the wind speed to 5m / s, freeze for 18min, and ensure that the center temperature of the mango pieces reaches -20℃.

[0082] (6) After sealing and packaging, transfer to a -18℃ freezer for storage, and maintain the relative humidity in the freezer at 92%.

[0083] The test results showed that after thawing, the mango pieces treated with the process of Comparative Example 2 had a juice loss rate of 9.5%, a hardness retention rate of 51.8%, a color change ΔE value of 3.2, and a sensory score of 78.3, indicating poor flavor and texture.

[0084] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A quick-freezing and freshness-locking process for mango chunks, characterized in that, Includes the following steps: Fresh mango chunks were soaked in a pretreatment solution containing fucoidan and mannitol; then drained and subjected to pre-cooling, rapid freezing and frozen storage in sequence.

2. The quick-freezing and freshness-locking process for mango chunks according to claim 1, characterized in that, The pretreatment solution contains 0.1%-0.5% fucoidan and 1%-3% mannitol.

3. The quick-freezing and freshness-locking process for mango chunks according to claim 2, characterized in that, The pretreatment solution also includes antioxidants.

4. The quick-freezing and freshness-locking process for mango chunks according to claim 1, characterized in that, The immersion conditions are: immersion at 4-8℃ for 15-30 minutes.

5. The quick-freezing and freshness-locking process for mango chunks according to claim 1, characterized in that, The precooling conditions are: precooling at 0-4℃ for 30-60 minutes.

6. The quick-freezing and freshness-locking process for mango chunks according to claim 1, characterized in that, The rapid freezing process involves using a liquid nitrogen freezer, a spiral freezer, or a tunnel freezer to rapidly lower the center temperature of the mango chunks to below -18°C.

7. The quick-freezing and freshness-locking process for mango chunks according to claim 6, characterized in that, When using a tunnel-type quick-freezing machine, the conditions for rapid freezing are: evaporation temperature of -40℃, wind speed of 4m / s, and freezing time of 20min.

8. The quick-freezing and freshness-locking process for mango chunks according to claim 6, characterized in that, When using a spiral quick-freezing machine, the conditions for rapid freezing are: evaporation temperature of -45℃, wind speed of 5m / s, and freezing time of 18min.

9. The quick-freezing and freshness-locking process for mango chunks according to claim 6, characterized in that, When using a liquid nitrogen quick-freezing machine, the conditions for rapid freezing are: freezing temperature -196℃ and freezing time 8 minutes.

10. The quick-freezing and freshness-locking process for mango chunks according to claim 1, characterized in that, The conditions for frozen storage are: frozen storage at -18℃ and relative humidity of 90%-95%.

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