A method for optimizing a freeze-dried food zero-addition antioxidant process

Abstract

This invention provides an optimized method for a zero-additive antioxidant process in freeze-dried food, relating to the field of food processing technology. The method includes the following steps: Freshly harvested matsutake mushrooms are pre-cooled at 1℃~3℃ for at least 1 hour, then packaged with ice packs and transported to the factory; the soil on the matsutake mushrooms is first manually removed, then the mushrooms are cleaned using a washing machine, soaked in clean water for half an hour, and finally rinsed three times with different water; the cleaned matsutake mushrooms are sliced, diced, or packaged according to grade and size in food trays and then placed in a freeze-drying chamber; the packaged matsutake mushrooms are then freeze-dried to maintain a moisture content of 1%-4%; using a vacuum inner bag and nitrogen-filled outer bag for freshness locking, the freeze-dried matsutake mushrooms are quantitatively packaged in an environment with air humidity below 30%. Without adding any additives, the freeze-dried product can remain dry and oxidized for a long time, extending the shelf life of the freeze-dried matsutake mushrooms and preventing them from easily rehydrating and oxidizing, which leads to rapid quality decline.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to an optimized method for zero-additive antioxidant processing of freeze-dried foods. Background Technology

[0002] With the increasing health awareness of consumers, "zero additives" has become one of the core development trends in the food industry. Consumers' demand for food has gradually shifted from "meeting basic needs" to "healthy, natural, and safe," requiring that no artificial antioxidants, preservatives, pigments, or other chemical additives be added during food processing, while retaining the food's own nutritional components and natural flavor. For example, matsutake mushrooms are rare wild fungi that cannot be artificially cultivated. They are highly seasonal, have a high water content, are easily spoiled, and have a very short shelf life. Traditional hot air drying or sun-drying methods can easily cause the loss of active ingredients, aroma volatilization, and browning, resulting in low added value. Freeze-drying technology, as an advanced food processing technology, can retain the shape, nutritional activity, and natural flavor of ingredients to the greatest extent through low-temperature pre-freezing, vacuum sublimation drying, and desorption drying processes. The retention rate of active substances such as vitamins and polyphenols can reach more than 95%, and the survival rate of probiotics is significantly improved. Therefore, it is widely used in the processing and production of fruits and vegetables, meat, aquatic products, and functional foods, and is one of the ideal technical paths to achieve "zero additives" food processing. It has also gradually become the mainstream processing method for matsutake mushrooms. However, matsutake mushrooms face serious oxidation and spoilage problems during processing and storage. This problem has become a key bottleneck restricting the development of zero-additive matsutake mushrooms. The core feature of freeze-drying technology is to remove moisture from the ingredients through vacuum sublimation, which makes the freeze-dried matsutake mushrooms form a large number of nano- to micro-scale microporous structures. Its specific surface area increases by 200-400 times compared with the unfrozen ingredients. The ingredients are in a highly active state and are very easy to come into contact with oxygen and undergo oxidation reactions. This leads to spoilage phenomena such as darkening of color, deterioration of flavor, degradation of nutrients, and the production of rancidity, which seriously affect product quality and shelf life, and even make them lose their edible value. To solve the oxidation problem of freeze-dried matsutake mushrooms, synthetic antioxidants (such as tert-butylhydroquinone, propyl gallate, etc.) or natural antioxidants (such as tea polyphenols, vitamin E, etc.) are usually added to inhibit the oxidation reaction through the action of antioxidants. However, the solution of adding antioxidants is difficult to meet the production needs and market expectations of zero-additive freeze-dried matsutake mushrooms. The use of artificially synthesized antioxidants does not conform to the health concept of "zero additives". Although natural antioxidants are relatively safe, their addition will change the natural flavor and taste of freeze-dried matsutake mushrooms and increase production costs. At the same time, their antioxidant effect is limited and it is difficult to inhibit the oxidation and deterioration of freeze-dried matsutake mushrooms (especially highly active and highly porous ingredients) in the long term. Summary of the Invention

[0003] This invention provides an optimized method for zero-additive antioxidant processing of freeze-dried foods, which addresses the aforementioned issues of the use of synthetic antioxidants not conforming to the health concept of "zero additives," the addition of natural antioxidants (which, while relatively safe, alters the natural flavor and texture of freeze-dried matsutake mushrooms and increases production costs), and the limited antioxidant effect of natural antioxidants, making it difficult to inhibit the oxidative deterioration of freeze-dried matsutake mushrooms (especially highly active, highly porous ingredients) in the long term.

[0004] To address the aforementioned technical problems, this invention discloses an optimized method for a zero-additive antioxidant process in freeze-dried foods, comprising the following steps: Step 1: Pre-treatment: Pre-cool the freshly collected food at 1℃~3℃ for more than 1 hour, then pack it with ice packs and transport it to the factory. Step 2: Cleaning: First, manually remove the dirt from the food, then use a cleaning machine to clean the food, soak the food in clean water for half an hour, and finally rinse the food with water three times. Step 3: Freeze-drying in sections: After washing, slice, cut, or divide the food into portions according to size and grade, and place them in food trays. Then place the food in the freeze-drying chamber to freeze-dry the food. Step 4: Quantitative packaging: Using an inner vacuum bag and an outer nitrogen-filled bag to lock in freshness, the freeze-dried food is quantitatively packaged in an environment with an air humidity of less than 30%.

[0005] The preferred freshly harvested food is matsutake mushroom.

[0006] Preferably, the specific method for freeze-drying matsutake mushrooms in step 3 is as follows: the packaged matsutake mushrooms are placed in a quick-freezing chamber and frozen at -50℃ to -70℃ for more than 12 hours. The frozen matsutake mushrooms are then placed in a freeze-drying chamber, and the temperature of the water-capturing chamber is controlled at around -40℃ to -50℃, the vacuum degree is controlled at 30Pa to 60Pa, and the heating plate temperature is controlled at 50℃ to 60℃. After about 56 hours, the freeze-dried matsutake mushrooms are removed from the freeze-drying chamber.

[0007] Preferably, in step 4, the inner and outer bags are made of either high-barrier materials such as aluminum foil or aluminum oxide.

[0008] Preferably, the freeze-drying chamber includes a shell, a freeze-drying cavity is provided at the front end of the shell, a chamber cover is installed at the front end of the freeze-drying cavity, a freeze-drying shelf is installed in the middle of the interior of the freeze-drying cavity, a number of food trays are placed on the freeze-drying shelf, water-capturing components are symmetrically provided on the left and right sides of the interior of the freeze-drying cavity, and a drain pipe and a vacuum pipe are respectively provided at the left and right ends of the shell, and the vacuum pipe is connected to a vacuum pump group.

[0009] Preferably, the water-catching component is a cryogenic coil, with a cooling medium flowing inside the cryogenic coil, and a cryogenic compressor is connected to the cryogenic coil, with a connecting pump installed on the side of the housing.

[0010] Preferably, the freeze-drying rack includes supports distributed on the four sides of the center of the freeze-drying chamber, and several placement grooves are evenly distributed along the vertical direction. A heating plate is installed between the placement grooves distributed on the same horizontal plane, and a heating coil is installed in the heating plate. A food tray is placed on the upper end of the heating plate.

[0011] Preferably, it also includes a functional component, which includes a plurality of rotating shafts rotatably arranged between the front and rear supports, the plurality of rotating shafts being fixedly connected to a plurality of rotating guide plates in a one-to-one correspondence, the plurality of rotating guide plates being fixedly arranged on the upper side of a plurality of heating plates in a one-to-one correspondence, the rotating guide plates distributed on the left and right sides of the same horizontal plane having an inclined section at their close ends, and the inclined sections of the left and right rotating guide plates being correspondingly fitted, the front and rear sides of the rotating guide plates being symmetrically provided with fixed guide plates, the rotating shaft passing through the front end of the support and being fixedly connected to gear two, gear two meshing with gear one, gear one being fixedly connected to connecting block one, connecting block one being fixedly connected to connecting block two, connecting block two being slidably connected to the support, a spring being fixedly provided between connecting block two and a fixed block, the fixed block being fixedly arranged on the support, and gear one on the lower side being correspondingly arranged on the front side of the placement groove.

[0012] Preferably, the water-catching component further includes a perforated plate slidably disposed at one end of a support distributed on the left and right sides, and the perforated plate is disposed on a support distributed on the front and back. An elastic rod is fixedly disposed between the lower end of the support and the lower end of the freeze-drying chamber. Several spring rods are fixedly disposed between the perforated plate and the lower end of the freeze-drying chamber. A fixed rack is correspondingly disposed in the middle of the perforated plate. The fixed rack is fixedly disposed at the upper end of the freeze-drying chamber. Several connecting shafts are symmetrically disposed on the front and back sides of the fixed rack. The several connecting shafts are evenly distributed on the perforated plate in the vertical direction. The connecting shafts are fixedly connected to the gear three and the turbulence fan. The gear three meshes with the fixed rack.

[0013] Preferably, two mounting plates are fixedly provided at the upper middle part of the housing, and a dual-head motor is fixedly installed between the two mounting plates. Rotary disks are fixedly connected to the motor shafts on the left and right sides of the dual-head motor, respectively. The rotating disks are eccentrically connected to drive shaft one, drive shaft one is rotatably connected to a rotating block, the rotating block is rotatably connected to drive shaft two, drive shaft two is rotatably connected to mating block one, mating block one is slidably disposed in the sliding groove of the connecting plate in the vertical direction, the inclined end of mating block one is in corresponding contact with the inclined end of mating block two, mating block two is slidably connected to the sliding groove in the horizontal direction, the end of mating block two away from mating block one is slidably connected to the mating plate in the vertical direction, the mating plate is fixedly connected to inclined block one, the inclined end of inclined block one is slidably connected to the inclined end of inclined block two, and inclined block two is fixedly connected to the through part of the bracket. The through part penetrates the upper end of the housing and is slidably connected to the housing.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. Using a double-layer bag, with an inner vacuum layer and an outer nitrogen-filled freshness-locking technology, freeze-dried matsutake mushrooms can be kept from rehydration and oxidation for a long time without any additives, thus extending their shelf life and preventing them from easily rehydrating and oxidizing, which would cause a rapid decline in quality. At the same time, the double-layer bag can protect the freeze-dried matsutake mushrooms and solve the problem of their fragility during transportation. Aluminum foil bags can be used. 2. Heating causes the moisture in the matsutake mushrooms to sublimate, and the sublimated gas is compressed into the water-capturing chamber and frozen using the vacuum principle. No drainage is required during the freeze-drying process. After the freeze-dried mushrooms are removed from the chamber, defrosting is performed to drain the water. The vacuum pump set has a 3-stage Rotch pump at the front and a water ring pump at the rear. During operation, the Rotch pump pressurizes the water ring pump to freeze the sublimated gas. A small amount of water is removed by the vacuum pump set to control the vacuum level. The low-temperature compressor uses refrigerant R404 and is connected to the water-capturing chamber to provide cold air to the chamber. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a process flow diagram of the present invention; Figure 2 This is a schematic diagram of the external structure of the freeze-drying chamber of the present invention; Figure 3 This is a schematic diagram of the internal structure of the freeze-drying chamber of the present invention; Figure 4 This is a schematic diagram of the bracket connection structure of the present invention; Figure 5 This is a schematic diagram of the through-hole connection structure of the present invention; Figure 6 This is a schematic diagram of the heating plate connection structure of the present invention; Figure 7 for Figure 6 A magnified structural diagram of region A in the diagram.

[0016] In the diagram: 1. Shell; 2. Compartment cover; 3. Drain pipe; 4. Vacuum tube; 5. Freeze-drying chamber; 6. Low-temperature coil; 7. Support; 8. Heating plate; 9. Heating coil; 10. Mesh plate; 11. Dual-head motor; 12. Mating plate; 13. Mounting plate; 14. Spring rod; 15. Baffle fan; 16. Gear three; 17. Placement groove; 18. Fixed guide plate; 19. Rotating guide plate; 20. Rotating disk; 21. Motor shaft; 22. Drive shaft one; 23. Rotating block; 24. Connecting plate; 25. Mating block two; 26. Sliding groove; 27. Mating block one; 28. Through part; 29. ​​Inclined block two; 30. Inclined block one; 31. Gear one; 32. Gear two; 33. Connecting block one; 34. Fixed block; 35. Spring; 36. Connecting block two; 37. Fixed rack; 38. Connecting shaft. Detailed Implementation

[0017] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0018] Furthermore, in this invention, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish components or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions and features of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0019] The present invention provides the following embodiments. Example 1: This embodiment of the invention provides an optimized method for the zero-additive antioxidant process of freeze-dried foods, such as... Figure 1 As shown, it includes the following steps: Step 1: Pre-treatment: Pre-cool the freshly collected food at 1℃~3℃ for more than 1 hour, then pack it with ice packs and transport it to the factory. Step 2: Cleaning: First, manually remove the dirt from the food, then use a cleaning machine to clean the food, soak the food in clean water for half an hour, and finally rinse the food with water three times. Step 3: Freeze-drying in sections: Slice the washed food into pieces or divide it into portions according to size and grade, and then place it in the freeze-drying chamber to freeze-dry the food. Step 4: Quantitative packaging: Using an inner vacuum bag and an outer nitrogen-filled bag to lock in freshness, the freeze-dried food is quantitatively packaged in an environment with an air humidity of less than 30%. The freshly harvested food is matsutake mushroom; Step 3 is as follows: The packaged matsutake mushrooms are placed in a quick-freezing chamber and frozen at -50℃ to -70℃ for more than 12 hours. The frozen matsutake mushrooms are then placed in a freeze-drying chamber. The temperature of the water-capturing chamber is controlled at around -40℃ to -50℃, the vacuum degree is controlled at 30Pa to 60Pa, and the heating temperature of the heating plate 8 is controlled at 50℃ to 60℃. After about 56 hours, the freeze-dried matsutake mushrooms are removed from the freeze-drying chamber. In step 4, the inner and outer bags are made of either high-barrier materials such as aluminum foil or aluminum oxide.

[0020] The working principle of the above technical solution is as follows: Taking matsutake mushrooms as an example, the freshly harvested matsutake mushrooms are first pre-cooled at 1℃-3℃ for more than 1 hour, then packaged with ice packs and transported to the factory. The mushrooms are first manually cleaned of soil, then washed thoroughly with a washing machine, and then soaked in clean water for half an hour. After rinsing three times with different water, pesticide residues are thoroughly removed. The cleaned matsutake mushrooms are then sliced, diced, or whole according to grade and size and packaged in food trays, which greatly improves the integrity of the freeze-dried mushrooms and reduces losses. The packaged matsutake mushrooms are then placed in a quick-freezing chamber and frozen at -50℃ to -70℃ for more than 12 hours. They are then transferred to a freeze-drying chamber, where the water-trapping chamber temperature is controlled at approximately -40℃ to -50℃, the vacuum degree is controlled at 30Pa to 60Pa, and the heating plate temperature is controlled at 50℃ to 60℃. The freeze-drying process is completed in about 56 hours, reducing the moisture content of the freeze-dried matsutake mushrooms to 1%-4%. The freeze-dried matsutake mushrooms are then removed from the freeze-drying chamber and packaged. Freeze-dried matsutake mushrooms are packaged in air with humidity below 30% using a double-layer bag design: an inner vacuum layer and an outer nitrogen-filled layer for freshness locking. Nitrogen technology not only combats oxidation but also prevents the freeze-dried food from becoming fragile during transportation. Furthermore, without any additives, it prevents the freeze-dried matsutake from rehydrating and oxidizing for extended periods, thus extending its shelf life and preventing rapid quality decline due to rehydration and oxidation. This addresses the issue of using synthetic antioxidants, which contradicts the "zero-additive" health concept. While natural antioxidants are relatively safe, their addition alters the natural flavor and texture of the freeze-dried matsutake and increases production costs. Moreover, their antioxidant effect is limited, making it difficult to maintain the oxidation and spoilage of freeze-dried matsutake (especially highly active, high-porosity ingredients) for a long period. The double-layer bag design, with an inner vacuum layer and an outer freshness-locking layer, effectively protects the freeze-dried matsutake and solves the problem of its fragility during transportation.

[0021] Example 2: Based on Example 1, such as Figures 2-6 As shown, the freeze-drying chamber includes a shell 1, a freeze-drying chamber 5 at the front end of the shell 1, a chamber cover 2 at the front end of the freeze-drying chamber 5, a freeze-drying shelf in the middle of the interior of the freeze-drying chamber 5, and several food trays placed on the freeze-drying shelf. Water trapping components are symmetrically arranged on the left and right sides of the interior of the freeze-drying chamber 5. Drain pipes 3 and vacuum pipes 4 are respectively provided at the left and right ends of the shell 1. Vacuum pipes 4 are connected to a vacuum pump group. The water-catching component is a low-temperature coil 6, which contains a cooling medium. The low-temperature coil 6 is connected to a low-temperature compressor, and a pump is installed on the side of the housing 1. The freeze-drying rack includes four supports 7 distributed on the front, back, left, and right sides of the freeze-drying chamber 5. The supports 7 are evenly spaced along the vertical direction with several placement grooves 17. A heating plate 8 is installed between the placement grooves 17 distributed on the same horizontal plane. A heating coil 9 is installed in the heating plate 8. A food tray is placed on the upper end of the heating plate 8.

[0022] The working principle of the above technical solution is as follows: When freeze-drying matsutake mushrooms, the vacuum pump unit is started. The vacuum pump unit absorbs air from the freeze-drying chamber 5 through the vacuum tube 4 to adjust the vacuum level of the freeze-drying chamber 5. The cover 2 can be opened to facilitate the removal and placement of food trays into the freeze-drying chamber 5. The cover 2 can be closed to form a sealed chamber in the freeze-drying chamber 5. The quick-frozen matsutake mushrooms are sent into the freeze-drying chamber 5. Several food trays are placed on the freeze-drying shelf. The matsutake mushrooms in the food trays are heated so that the water in the quick-frozen matsutake mushrooms undergoes vacuum sublimation. Water-catching components are set on the left and right sides of the freeze-drying chamber 5. By adjusting the temperature of the water-catching components, the temperature of the left and right sides of the freeze-drying chamber 5 (i.e., the water-catching chamber) is controlled at -40℃ to -50℃. The sublimated gaseous water is condensed and collected, thus achieving the purpose of capturing water in the matsutake mushrooms and completing the freeze-drying of the matsutake mushrooms. The drain pipe 3 is set to drain the water in the freeze-drying chamber 5. Specifically, when the water-catching component is working, the placement groove 17 is used to position the heating plate 8. The heating coil 9 heats the heating plate 8, maintaining its temperature between 50°C and 60°C. This heats the matsutake mushrooms on the heating plate 8, causing the moisture in the mushrooms to sublimate (water sublimates into water vapor). The low-temperature compressor uses refrigerant R404, which is circulated through the low-temperature coil 6, thereby lowering the temperature of the low-temperature coil 6 and its installation area (water-catching chamber). At -40℃ to -50℃, the water vapor sublimated from the matsutake mushrooms is rapidly condensed into ice. The front electrode of the vacuum pump group is a 3-stage Roots pump, and the rear electrode is a water ring pump. When the vacuum pump group is working, the Roots pump pressurizes the water ring pump, quickly drawing the water vapor generated by sublimation to the water-catching chamber to freeze. A small amount of water is removed by the vacuum pump, thereby stabilizing and controlling the vacuum degree in the freeze-drying chamber 5 and ensuring that the freeze-drying process proceeds normally. No drainage is required during the freeze-drying process. After the freeze-drying is completed, the matsutake mushrooms are removed from the freeze-drying chamber 5, and the water from the defrosting in the water-catching chamber is drained out through the drain pipe 3.

[0023] Example 3: Based on Example 2, such as Figures 2-7As shown, it also includes functional components, including a plurality of rotating shafts rotatably arranged between the front and rear supports 7. The plurality of rotating shafts are fixedly connected to a plurality of rotating guide plates 19 in a one-to-one correspondence. The plurality of rotating guide plates 19 are arranged on the upper side of a plurality of heating plates 8 in a one-to-one correspondence. The rotating guide plates 19 distributed on the left and right sides of the same horizontal plane have inclined sections at their close ends, and the inclined sections of the left and right rotating guide plates 19 are correspondingly fitted. Fixed guide plates 18 are symmetrically arranged on the front and rear sides of the rotating guide plates 19. The rotating shaft passes through the front end of the support 7 and is fixedly connected to the second gear 32. The second gear 32 meshes with the first gear 31. The first gear 31 is fixedly connected to the first connecting block 33. The first connecting block 33 is fixedly connected to the second connecting block 36. The second connecting block 36 is slidably connected to the support 7. A spring 35 is fixedly arranged between the second connecting block 36 and the fixed block 34. The fixed block 34 is fixedly arranged on the support 7. The first gear 31 on the lower side is correspondingly arranged on the front side of the placement groove 17.

[0024] The working principle of the above technical solution is as follows: The rotating guide plate 19 is positioned vertically when adjusting the vacuum level in the freeze-drying chamber 5 and the temperature of the water-collecting chamber and the heating plate 8. This facilitates the separation of the space above the heating plate 8 (i.e., the heating chamber) from the water-collecting chamber, which is beneficial for adjusting the temperature of the water-collecting chamber and the heating chamber. After the temperatures of the water-collecting chamber and the heating chamber stabilize, the chamber cover 2 is opened, and the connecting block 2 36 is pulled. The connecting block 2 36 drives the gear 1 31 to move upward through the connecting block 1 33. The spring 35 is stretched, causing the gear 1 31 to disengage from the gear 2 32. Then, the rotating guide plate 19 is controlled to rotate. When the rotating guide plate 19 rotates, it drives the gear 2 32 to rotate through the rotating shaft. When rotating the rotating guide plate 19 to the horizontal position, the left rotating shaft is rotated first. After rotating the guide plate 19 on the right side, the inclined sections of the left and right rotating guide plates 19 are aligned and then the connecting block 2 36 is released. Under the elastic action of the spring 35, the connecting block 2 36 can be moved downward to return to its original position. The connecting block 2 36 drives the gear 1 31 to mesh with the gear 2 32 through the connecting block 1 33. At this time, the rotating guide plate 19 no longer rotates. The lower end surfaces of the fixed guide plate 18 and the rotating guide plate 19, which have been rotated to the horizontal and aligned, remain flush. The lower ends of the rotating guide plate 19 and the fixed guide plate 18 are both inclined, and the inclined direction is towards the water trap. After the water in the matsutake mushroom is vacuum sublimated and forms a gaseous state, it can gather towards the water trap, which can further improve the water trapping efficiency of the water trap. Except for the uppermost gear 31, after the lower gear 31 returns to its original position and meshes with the second gear 32, it can be set in front of the placement groove 17. At this time, the second gear 32 limits the front of the heating plate 8, and the freeze-drying chamber 5 limits the rear of the heating plate 8. The cooperation between the placement groove 17 and the heating plate 8 allows the heating plate 8 to be flexibly disassembled, making it convenient to disassemble and clean the heating plate 8, and preventing water stains from remaining on the upper part of the heating plate 8 after long-term operation, which would affect the heating efficiency of the heating plate 8. After the guide plate 19 is rotated to a horizontal position, the food tray containing the food to be freeze-dried is placed on the heating plate 8. Then the cover 2 is closed, and the temperature of the water trapping chamber and the temperature of the heating chamber are adjusted again. Since the temperature of the water trapping chamber and the temperature of the heating chamber have been adjusted initially, the adjustment efficiency of the temperature of the water trapping chamber and the temperature of the heating chamber can be accelerated after the food tray is placed on the heating plate 8, thereby improving the freeze-drying efficiency of matsutake mushrooms.

[0025] Example 4: Based on Example 1, as follows Figures 2-7 As shown, the water-catching assembly also includes a mesh plate 10 slidably disposed at one end of a support 7 distributed on the left and right sides, and the mesh plate 10 is disposed on the support 7 distributed in the front and back. An elastic rod is fixedly disposed between the lower end of the support 7 and the lower end of the freeze-drying chamber 5. Several spring rods 14 are fixedly disposed between the mesh plate 10 and the lower end of the freeze-drying chamber 5. A fixed rack 37 is correspondingly disposed in the middle of the mesh plate 10. The fixed rack 37 is fixedly disposed at the upper end of the freeze-drying chamber 5. Several connecting shafts 38 are symmetrically disposed on the front and rear sides of the fixed rack 37. The several connecting shafts 38 are evenly distributed on the mesh plate 10 in the vertical direction. The connecting shafts 38 are rotatably connected to the mesh plate 10. The connecting shafts 38 are fixedly connected to the gear 16 and the baffle 15. The gear 16 meshes with the fixed rack 37. Two mounting plates 13 are fixedly provided at the upper middle part of the housing 1. A dual-head motor 11 is fixedly installed between the two mounting plates 13. Rotary disks 20 are fixedly connected to the motor shafts 21 on the left and right sides of the dual-head motor 11, respectively. The rotating disks 20 are eccentrically connected to drive shaft 1 22. Drive shaft 1 22 is rotatably connected to rotating block 23. Rotating block 23 is rotatably connected to drive shaft 22. Drive shaft 22 is rotatably connected to mating block 27. Mating block 27 is slidably disposed in the sliding groove 26 of the connecting plate 24 in the vertical direction. The inclined end of 7 contacts the inclined end of the mating block 25. The mating block 25 is slidably connected to the sliding groove 26 in the left and right direction. The end of the mating block 25 away from the mating block 27 is slidably connected to the mating plate 12 in the up and down direction. The mating plate 12 is fixedly connected to the inclined block 30. The inclined end of the inclined block 30 is slidably connected to the inclined end of the inclined block 29. The inclined block 29 is fixedly connected to the through part 28 of the bracket 7. The through part 28 penetrates the upper end of the housing 1 and is slidably connected to the housing 1.

[0026] The working principle of the above technical solution is as follows: When the food tray is placed on the heating plate 8 for freeze drying, the dual-head motor 11 is started. The dual-head motor 11 drives the motor shaft 21 to rotate, the motor shaft 21 drives the rotating disk 20 to rotate, the rotating disk 20 drives the drive shaft 22 to rotate, the drive shaft 22 drives the rotating block 23 to move up and down, the rotating block 23 drives the mating block 27 to move up and down reciprocally. After the mating block 27 moves downward and contacts the mating block 25, it pushes the mating block 25 downward. The mating block 25 drives the connecting plate 24 to move downward, the connecting plate 24 drives the mesh plate 10 to move downward, and the mesh plate 10 drives the spring rod 14 to compress. When the mating block 27 moves upward, the mating block 27 no longer squeezes the mating block 25. Under the elastic action of the spring rod 14, the mesh... The plate 10 moves upward, achieving the purpose of the perforated plate 10 moving up and down. When the perforated plate 10 moves up and down, it can drive several connecting shafts 38 to move. Since the fixed rack 37 is fixedly connected to the upper end of the freeze-drying chamber 5, the fixed rack 37 remains stationary. The connecting shafts 38 drive the gear 16 and the baffle 15 to move up and down. When the gear 16 moves up and down along the fixed rack 37, it drives the connecting shaft 38 to rotate. The connecting shaft 38 drives the baffle 15 to rotate. After the sublimated gaseous water passes through the mesh of the perforated plate 10 and the baffle 15, it moves in an irregular state, which can improve the contact effect between the gaseous water and the low-temperature coil 6, thereby improving the water capture effect of the low-temperature coil 6 and minimizing the entry of the sublimated gaseous water into the vacuum tube 4. After the food tray is placed on the heating plate 8, the support 7 moves downward under gravity, causing the elastic rod to compress. As the moisture in the matsutake mushrooms sublimates, the weight of the matsutake mushrooms decreases, and the sublimated moisture also decreases. The weight of the support 7, the heating plate 8, and the matsutake mushrooms decreases. Under the elastic action of the elastic rod, the support 7 gradually moves upward. The support 7 causes the second inclined block 29 to move downward, and the second inclined block 29 causes the first inclined block 30 to move away from the through-hole 28. The first inclined block 30, through the mating plate 12, causes the second mating block 25 to move. The second matsutake block 25 moves towards the inclined end away from the first matsutake block 27, increasing the gap between the inclined ends of the first matsutake block 27 and the second matsutake block 25, thereby reducing the vertical movement of the mesh plate 10 until the matsutake freeze-drying is completed. At this point, there is no more sublimated water produced, and the mesh plate 10 no longer moves up and down. The vertical movement of the mesh plate 10 is automatically adjusted according to the weight of the matsutake. Even if the weight of the matsutake placed in the freeze-drying chamber 5 is large, the movement of the mesh plate 10 can be automatically adjusted to ensure that the mesh plate 10 can fully disturb the sublimated water.

[0027] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An optimized method for a zero-additive antioxidant process in freeze-dried foods, characterized in that: Includes the following steps: Step 1: Pre-treatment: The freshly collected food is pre-cooled at 1℃~3℃ for more than 1 hour, then packaged with ice packs and transported to the factory; Step 2: Cleaning: First, manually remove the dirt from the food, then use a cleaning machine to clean the food, soak the food in clean water for half an hour, and finally rinse the food with water three times. Step 3: Freeze-drying in sections: After washing, slice, cut, or divide the food into portions according to size and grade, and place them in food trays. Then place the trays in the freeze-drying chamber to freeze-dry the food. Step 4: Quantitative packaging: Using an inner vacuum bag and an outer nitrogen-filled bag to lock in freshness, the freeze-dried food is quantitatively packaged in an environment with an air humidity of less than 30%.

2. The optimized method for a zero-additive antioxidant process in freeze-dried food according to claim 1, characterized in that: The freshly harvested food is matsutake mushroom.

3. The optimized method for a zero-additive antioxidant process in freeze-dried food according to claim 2, characterized in that: Step 3 is to freeze-dry the matsutake mushrooms. The specific method is as follows: the packaged matsutake mushrooms are sent into the quick-freezing chamber and frozen at -50℃ to -70℃ for more than 12 hours. The frozen matsutake mushrooms are then sent into the freeze-drying chamber. The temperature of the water trap is controlled at around -40℃ to -50℃, the vacuum degree is controlled at 30Pa to 60Pa, and the heating plate (8) is controlled at 50℃ to 60℃. After about 56 hours, the freeze-dried matsutake mushrooms are removed from the freeze-drying chamber.

4. The optimized method for a zero-additive antioxidant process in freeze-dried food according to claim 1, characterized in that: In step 4, the inner and outer bags are made of high-barrier materials, including either aluminum foil or aluminum oxide.

5. The optimized method for a zero-additive antioxidant process in freeze-dried food according to claim 3, characterized in that: The freeze-drying chamber includes a shell (1), a freeze-drying chamber (5) at the front end of the shell (1), a chamber cover (2) at the front end of the freeze-drying chamber (5), a freeze-drying shelf in the middle of the interior of the freeze-drying chamber (5), several food trays placed on the freeze-drying shelf, water trapping components symmetrically arranged on the left and right sides of the interior of the freeze-drying chamber (5), and a drain pipe (3) and a vacuum pipe (4) respectively at the left and right ends of the shell (1), with the vacuum pipe (4) connected to a vacuum pump group.

6. The optimized method for a zero-additive antioxidant process in freeze-dried food according to claim 5, characterized in that: The water-catching component is a low-temperature coil (6), and a cooling medium flows inside the low-temperature coil (6). The low-temperature coil (6) is connected to a low-temperature compressor, and a connecting pump is installed on the side of the housing (1).

7. The optimized method for a zero-additive antioxidant process in freeze-dried food according to claim 6, characterized in that: The freeze-drying rack includes a support (7) distributed on the front, back, left and right sides of the freeze-drying chamber (5). The support (7) is evenly spaced along the vertical direction with several placement grooves (17). A heating plate (8) is installed between the placement grooves (17) distributed on the same horizontal plane. A heating coil (9) is installed in the heating plate (8). A food tray is placed on the upper end of the heating plate (8).

8. The optimized method for a zero-additive antioxidant process in freeze-dried food according to claim 7, characterized in that: It also includes functional components, including a number of rotating shafts rotatably arranged between the front and rear distributed brackets (7), the number of rotating shafts being fixedly connected to a number of rotating guide plates (19) one by one, the number of rotating guide plates (19) being arranged one by one on the upper side of a number of heating plates (8), the rotating guide plates (19) distributed on the same horizontal plane having inclined sections at their close ends, and the inclined sections of the left and right distributed rotating guide plates (19) correspondingly fitting together, and fixed guide plates (18) symmetrically arranged on the front and rear sides of the rotating guide plates (19), the rotating shafts The gear passes through the front end of the bracket (7) and is fixedly connected to the second gear (32). The second gear (32) meshes with the first gear (31). The first gear (31) is fixedly connected to the first connecting block (33). The first connecting block (33) is fixedly connected to the second connecting block (36). The second connecting block (36) is slidably connected to the bracket (7). A spring (35) is fixedly provided between the second connecting block (36) and the fixed block (34). The fixed block (34) is fixedly set on the bracket (7). The first gear (31) on the lower side is correspondingly set on the front side of the placement groove (17).

9. The optimized method for a zero-additive antioxidant process in freeze-dried food according to claim 6, characterized in that: The water-catching assembly also includes a mesh plate (10) that is slidably disposed at one end of a support (7) that is distributed on the left and right sides and is located away from each other. The mesh plate (10) is disposed on the support (7) that is distributed in the front and back. An elastic rod is fixedly disposed between the lower end of the support (7) and the lower end of the freeze-drying chamber (5). Several spring rods (14) are fixedly disposed between the mesh plate (10) and the lower end of the freeze-drying chamber (5). A fixed rack (37) is provided in the middle of the mesh plate (10). The fixed rack (37) is fixedly disposed at the upper end of the freeze-drying chamber (5). Several connecting shafts (38) are symmetrically disposed on the front and back sides of the fixed rack (37). Several connecting shafts (38) are evenly distributed on the mesh plate (10) in the up and down direction. The connecting shafts (38) are fixedly connected to the gear three (16) and the turbulence fan (15). The gear three (16) meshes with the fixed rack (37).

10. An optimized method for a zero-additive antioxidant process in freeze-dried food according to claim 9, characterized in that: Two mounting plates (13) are fixedly provided at the middle of the upper end of the housing (1). The two mounting plates (13) are fixedly installed between the two mounting plates (11). The motor shafts (21) on the left and right sides of the dual-head motor (11) are respectively fixedly connected to rotating disks (20). The rotating disks (20) are eccentrically connected to drive shaft one (22). Drive shaft one (22) is rotatably connected to rotating block (23). Rotating block (23) is rotatably connected to drive shaft two. Drive shaft two is rotatably connected to mating block one (27). The mating block one (27) is slidably disposed in the sliding groove (26) of the connecting plate (24) in the vertical direction. The inclined end of the first (25) contacts the inclined end of the second (26) and slides the sliding groove (26) in the left and right direction. The end of the second (25) away from the first (27) slides the mating plate (12) in the up and down direction. The mating plate (12) is fixedly connected to the first (30). The inclined end of the first (30) slides the inclined end of the second (29) and slides the inclined end of the second (29). The second (29) is fixedly connected to the through part (28) of the bracket (7). The through part (28) passes through the upper end of the shell (1) and slides the through part (28) with the shell (1).

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