Nuts sterilization and preservation device and method

Abstract

The application discloses a nut sterilization and preservation device and a sterilization and preservation method, relates to the technical field of food processing, and the nut sterilization and preservation device comprises a first sterilization unit, a second sterilization unit and a preservation unit, the first sterilization unit, the second sterilization unit and the preservation unit are sequentially arranged along a material conveying direction, the first sterilization unit is used for ozone-ultraviolet sterilization of shelled nuts, the second sterilization unit is used for cold plasma sterilization of the shelled nuts, and the preservation unit is used for storing the shelled nuts in an inert gas atmosphere; the whole process is low-temperature non-thermal processing, the original quality and nutrients of the nuts are maximally retained, chemical residues are not formed on the surface of the nuts, nut quality is not damaged or hidden dangers are not caused, the shelled nuts can be subjected to uniform sterilization treatment on wrinkles, kernel gaps and seed coat micropores, the stability of preservation and storage is improved, the sensory quality and commodity value of nut finished products are improved, and therefore, the high-quality development of the shelled nut deep processing industry can be promoted.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a nut sterilization and preservation device and method. Background Technology

[0002] Nuts, such as walnuts, are rich in unsaturated fatty acids, plant protein, vitamins, and various minerals, making them highly nutritious and popular among consumers. However, after the inner seed coat is removed, the quality stability of walnut kernels decreases significantly, resulting in significant processing and storage limitations. On the one hand, the inner seed coat, as a natural protective structure of nuts, loses its effective physical protective layer after removal. On the other hand, nuts themselves have a high oil content, a loose internal structure, and obvious pores, making them susceptible to microbial contamination from the environment, leading to mold and spoilage. Furthermore, the oil in the kernel is prone to oxidative rancidity, producing a rancid odor and drastically shortening the product's shelf life. This severely restricts the industrial production, storage, and large-scale application of peeled nuts.

[0003] To address the issues of easy contamination and oxidation in peeled nuts, current processing techniques commonly employ various conventional sterilization and preservation methods. Among these, heat treatment methods, such as hot air and hot water treatment, rely on high temperatures for sterilization and antibacterial effects. However, these high temperatures cause significant heat damage to the nuts and kernels, not only destroying heat-sensitive nutrients like proteins and vitamins, leading to their loss, but also altering their original flavor and texture, resulting in deteriorated product quality and making them unsuitable for high-end nut processing. While chemical disinfectants can effectively kill bacteria, they often leave residues on the kernel surface, posing food safety risks and failing to meet green and healthy food processing standards. Furthermore, chemical reagents can damage the microstructure of the kernel surface, exacerbating quality loss. Single ultraviolet irradiation is a common non-thermal sterilization technology that can effectively avoid heat damage and chemical residues. However, this treatment method has prominent problems such as many blind spots and uneven light coverage. The wrinkles and stacked parts on the surface of nuts such as walnut kernels cannot be effectively sterilized. The overall sterilization and preservation uniformity is poor and the treatment effect is unstable, making it difficult to achieve batch and standardized industrial processing and production.

[0004] In summary, current conventional processing technologies for peeled nuts generally suffer from a series of problems, such as uneven processing results, severe quality damage, safety hazards, or poor preservation stability. These technologies fail to effectively address the core issues of peeled nuts, such as susceptibility to microbial contamination, easy oxidation and rancidity, and poor storage stability, which seriously restricts the high-quality development of the deep processing industry for peeled nuts. Summary of the Invention

[0005] The purpose of this invention is to provide a nut sterilization and preservation device and method to solve the problems existing in the prior art and promote the high-quality development of the deep processing industry of peeled nuts.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a nut sterilization and preservation device, comprising a first sterilization unit, a second sterilization unit, and a preservation unit. The first sterilization unit, the second sterilization unit, and the preservation unit are arranged sequentially along the material conveying direction. The first sterilization unit is used to perform ozone-ultraviolet sterilization on the peeled nuts, the second sterilization unit is used to perform cold plasma sterilization on the peeled nuts, and the preservation unit is used to store the peeled nuts in an inert gas atmosphere.

[0007] In some embodiments, the first sterilization unit includes a first sterilization chamber, in which at least one first tray is disposed. The first tray is used to hold the peeled nuts, and the peeled nuts are laid flat in the first tray. An ozone sterilization section and an ultraviolet sterilization section are disposed on the inner wall of the first sterilization chamber. The ozone sterilization section is used to expose the peeled nuts in the first sterilization chamber to an ozone atmosphere, and the ultraviolet sterilization section is used to irradiate the peeled nuts on the first tray with ultraviolet light.

[0008] In some embodiments, the first tray has a plurality of first holes, the diameter of which is smaller than the diameter of the peeled nuts, and the first holes allow ultraviolet light to shine from the bottom of the first tray upwards onto the peeled nuts on the first tray.

[0009] In some embodiments, the nut sterilization and preservation device further includes a transmission unit, with a first end of the transmission unit located near the outlet of the first sterilization chamber and a second end of the transmission unit located near the inlet of the preservation unit. The second sterilization unit is located in the middle of the transmission unit, and the transmission unit is used to transport the peeled nuts from the first end of the transmission unit to the second end of the transmission unit.

[0010] In some embodiments, the second sterilization unit includes a second sterilization chamber, in which a cold plasma generator and a first gas control unit are disposed. The cold plasma generator is used to discharge towards the peeled nuts located in the second sterilization chamber, and the first gas control unit is used to keep the second sterilization chamber in a dry air, nitrogen, or nitrogen-air mixture atmosphere.

[0011] In some embodiments, the preservation unit includes a preservation cavity, and a second gas control unit is provided in the preservation cavity to store the peeled nuts located in the preservation cavity in an inert gas atmosphere.

[0012] In some embodiments, the conveying unit includes a conveyor belt, and the nut sterilization and preservation device further includes a uniform conveying unit. The uniform conveying unit includes a vibrator, a uniform scraper, and a guide plate. The vibrator is fixedly mounted on the conveyor belt to apply reciprocating vibration to the peeled nuts on the conveyor belt. The uniform scraper is disposed on the top of the conveyor belt located between the discharge port of the first sterilization chamber and the second sterilization unit. The bottom edge of the uniform scraper has a gap with the conveyor belt. The gap is adjustable so that it is between the thickness of a single layer of peeled nuts and the thickness of a double layer of peeled nuts. The guide plates are respectively disposed on both sides of the conveyor belt to prevent the peeled nuts on the conveyor belt from overflowing from both sides of the conveyor belt.

[0013] In some embodiments, the cold plasma generator is a dielectric barrier discharge plasma generator, which includes multiple processing heads. Each processing head is disposed in the second sterilization chamber via a movable part. Each movable part can change the position and orientation of each processing head corresponding to it in the second sterilization chamber, so that the processing head can discharge toward the peeled nuts located in the second sterilization chamber.

[0014] In some embodiments, the nut sterilization and preservation device further includes a closed box, in which the first sterilization unit, the second sterilization unit, the preservation unit and the transmission unit are all disposed, and an entrance and exit are provided on the side of the closed box, and an access door capable of opening or closing the entrance and exit is installed at the entrance and exit.

[0015] The present invention also provides a method for sterilizing and preserving nuts, using the nut sterilization and preservation device described in any of the above claims, comprising the following steps: The peeled nuts are placed in the first sterilization unit, and the peeled nuts are sterilized by ozone-ultraviolet sterilization through the first sterilization unit; The peeled nuts are conveyed to the second sterilization unit, where they are sterilized by cold plasma. The peeled nuts are transported to the preservation unit, where they are stored in an inert gas atmosphere.

[0016] The present invention achieves the following technical effects compared to the prior art: This invention provides a nut sterilization and preservation device and method. The first sterilization unit uses ozone-ultraviolet sterilization on peeled nuts. Ultraviolet light irradiation destroys bacterial DNA on the nut surface, rapidly reducing the number of viable bacteria. Ozone penetrates nut folds, kernel crevices, and seed coat micropores, eliminating ultraviolet light blind spots and effectively inactivating bacterial vegetative cells and surface mold. Simultaneously, it destroys the mold biofilm protective layer, weakening the resistance of stubborn microbial spores. The second sterilization unit uses cold plasma sterilization on the peeled nuts, utilizing high-energy particles generated by a high-frequency, high-voltage electric field. The process involves bombarding to thoroughly penetrate the cell walls and cell membranes of stubborn mold spores and bacterial spores, destroying intracellular functional proteins and genetic material, and preventing microbial repair and regeneration. The preservation unit stores the peeled nuts in an inert gas atmosphere, which can quickly replace oxygen and moisture in the gaps between materials and the packaging cavity, completely isolating the contact channels between nut oils and oxygen, inhibiting the oxidation and rancidity of unsaturated fatty acids from the source, and inhibiting the revival and reproduction of residual trace aerobic microorganisms and mold spores. This solidifies the results of the first two stages of sterilization and detoxification, and prevents secondary pollution and mold recurrence after sterilization. Compared with existing single sterilization and preservation processes, the entire process is low-temperature and non-thermal processing, which preserves the original quality and nutrition of nuts to the maximum extent. It does not leave chemical residues on the surface of nuts, avoiding damage to nut quality or safety hazards. It can uniformly sterilize nut wrinkles, kernel gaps and seed coat micropores, and improve the stability of preservation and storage. It can also completely preserve the nutrients and crisp texture of nuts, greatly improving the sensory quality and commercial value of finished nuts, thereby promoting the high-quality development of the deep processing industry of peeled nuts. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the enclosed box structure in some embodiments of Example 1; Figure 2 This is a schematic diagram of the nut sterilization and preservation device in some embodiments of Example 1; Figure 3 This is a schematic diagram of the internal structure of the nut sterilization and preservation device in some embodiments of Example 1.

[0019] In the diagram: 1-First sterilization unit; 11-First sterilization chamber; 12-First tray; 13-First vertical box; 14-First guide rail; 2-Second sterilization unit; 21-Cold plasma generator; 211-Processing head; 3-Preservation unit; 31-Second vertical box; 32-Second tray; 4-Transfer unit; 41-Conveyor belt; 5-Uniform conveying unit; 51-Vibration support; 52-Vibration pallet; 6-Enclosed box. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide a nut sterilization and preservation device and method to solve the problems existing in the prior art and promote the high-quality development of the deep processing industry of peeled nuts.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1 This invention provides a nut sterilization and preservation device, see reference. Figures 1-3The system includes a first sterilization unit 1, a second sterilization unit 2, and a preservation unit 3, arranged sequentially along the material conveying direction. The first sterilization unit 1 performs ozone-ultraviolet sterilization on the peeled nuts, the second sterilization unit 2 performs cold plasma sterilization on the peeled nuts, and the preservation unit 3 stores the peeled nuts in an inert gas atmosphere. The first sterilization unit 1 performs ozone-ultraviolet sterilization on the peeled nuts, destroying bacterial DNA on the nut surface through ultraviolet light irradiation, rapidly reducing the number of viable bacteria on the surface. Ozone penetrates the nut folds, kernel crevices, and seed coat micropores, eliminating ultraviolet light blind spots and effectively inactivating bacterial vegetative cells and surface mold. Simultaneously, it destroys the mold biofilm protective layer, weakening the resistance of stubborn microbial spores. The second sterilization unit 2 performs cold plasma sterilization on the peeled nuts, using high-energy particles generated by a high-frequency, high-voltage electric field to completely penetrate any remaining stubborn microorganisms. The cell walls and cell membranes of mold spores and bacterial spores damage intracellular functional proteins and genetic material, preventing microbial repair and regeneration. Preservation unit 3 stores the peeled nuts in an inert gas atmosphere. This inert gas rapidly replaces oxygen and moisture in the material gaps and packaging cavity, completely isolating the nut oils from oxygen, inhibiting the oxidation and rancidity of unsaturated fatty acids at the source, and suppressing the resurgence and reproduction of residual trace aerobic microorganisms and mold spores. This solidifies the results of the first two stages of sterilization and detoxification, preventing secondary contamination and mold recurrence after sterilization. Compared to existing single sterilization and preservation processes, this low-temperature, non-thermal processing maximizes the preservation of the nuts' original quality and nutrition, avoids chemical residues on the nut surface, prevents damage to nut quality or safety hazards, and provides uniform sterilization of nut wrinkles, kernel crevices, and seed coat micropores. It also improves the stability of preservation and storage, greatly enhancing the sensory quality and commercial value of the finished nut product, thus promoting the high-quality development of the peeled nut deep processing industry.

[0024] In some embodiments, the first sterilization unit 1 includes a first sterilization chamber 11, within which at least one first tray 12 is disposed. The first tray 12 is used to hold peeled nuts, which are laid flat in the first tray 12. An ozone sterilization section and an ultraviolet sterilization section are disposed on the inner wall of the first sterilization chamber 11. The ozone sterilization section is used to expose the peeled nuts in the first sterilization chamber 11 to an ozone atmosphere, and the ultraviolet sterilization section is used to irradiate the peeled nuts on the first tray 12 with ultraviolet light. By irradiating the peeled nuts on the first tray 12 with ultraviolet light, the bacterial DNA on the nut surface is directly destroyed, rapidly reducing the number of viable bacteria on the surface. By exposing the peeled nuts in the first sterilization chamber 11 to an ozone atmosphere, the ultraviolet light penetrates the nut folds, kernel crevices, and seed coat micropores, eliminating ultraviolet light irradiation dead zones, effectively inactivating bacterial vegetative cells and surface mold, while simultaneously destroying the protective layer of mold biofilm and weakening the resistance of stubborn microbial spores.

[0025] In some embodiments, the first tray 12 is provided with a plurality of first holes, the diameter of which is smaller than the diameter of the peeled nuts. The first holes allow ultraviolet light to shine from the bottom of the first tray 12 upward onto the peeled nuts on the first tray 12, thereby enabling ultraviolet light to shine not only from the top of the peeled nuts but also from the bottom of the peeled nuts, reducing the blind spots of the peeled nuts on the first tray 12 and improving the uniformity of the irradiation of the peeled nuts on the first tray 12.

[0026] In some embodiments, the first sterilization chamber 11 is enclosed by a first vertical box 13. Multiple layers of first guide rails 14 are provided on the inner wall of the first vertical box 13 to support multiple stacked first trays 12. One side of the first vertical box 13 is open to facilitate the placement and removal of the first trays 12. The ultraviolet sterilization unit includes ultraviolet lamps disposed on the inner wall of the first vertical box 13. The specific number and direction of the ultraviolet lamps are arranged to irradiate the tops of the peeled nuts on each first tray 12. Ideally, the ozone sterilization unit includes a first air inlet at the bottom of the first vertical housing 13 and a first air outlet at the top of the first vertical housing 13. The first air inlet is used to introduce ozone into the first sterilization chamber 11, and the first air outlet is used to discharge the gas inside the first sterilization chamber 11. The bottom-inlet and top-outlet design allows for unidirectional gas flow within the first sterilization chamber 11, expelling air from the chamber and ensuring the shelled nuts inside are in an ozone atmosphere. In some embodiments, ultraviolet lamps are installed on the inner top wall, inner bottom wall, and all circumferential inner side walls of the first vertical housing 13 to further reduce the blind spots of irradiation on the shelled nuts on the first tray 12. In some embodiments, a reflector is also provided inside the first vertical housing 13 to further reduce the blind spots of irradiation on the shelled nuts on the first tray 12.

[0027] In other embodiments, the first sterilization chamber 11 is enclosed by a first storage bin, in which peeled nuts are piled. A first inlet is provided at the top of the first storage bin, and a first outlet is provided at the bottom of the first storage bin. A stirring mechanism is provided inside the first storage bin, and an ultraviolet lamp is provided on the inner top wall of the first storage bin. A first air inlet for conveying ozone and a first air outlet for discharging gas from the first sterilization chamber 11 are also provided on the first storage bin. The stirring mechanism stirs the peeled nuts in the first storage bin so that the peeled nuts are fully irradiated by the ultraviolet lamp and are placed in an ozone atmosphere.

[0028] In some embodiments, the nut sterilization and preservation device further includes a transmission unit 4. The first end of the transmission unit 4 is located near the discharge port of the first sterilization chamber 11, and the second end of the transmission unit 4 is located near the inlet of the preservation unit 3. The second sterilization unit 2 is located in the middle of the transmission unit 4. The transmission unit 4 is used to transport the peeled nuts from the first end of the transmission unit 4 to the second end of the transmission unit 4, so that the peeled nuts pass through the second sterilization unit 2. The second sterilization unit 2 sterilizes the peeled nuts with cold plasma. The high-energy particles generated by the high-frequency high-voltage electric field physically bombard the nuts, thoroughly breaking through the cell walls and cell membranes of the stubborn residual mold spores and bacterial spores, destroying intracellular functional proteins and genetic material, and preventing microbial repair and regeneration.

[0029] In some embodiments, the second sterilization unit 2 includes a second sterilization chamber, in which a cold plasma generator 21 and a first gas control unit are disposed. The cold plasma generator 21 is used to discharge towards the peeled nuts located in the second sterilization chamber. The first gas control unit is used to keep the second sterilization chamber in a dry air, nitrogen, or nitrogen-air mixture atmosphere. The cold plasma generator 21 outputs high-frequency high-voltage alternating current to excite the gas inside the second sterilization chamber to undergo an ionization reaction, continuously generating high concentrations of active oxygen free radicals, active nitrogen free radicals, ozone, singlet oxygen, and hydrogen peroxide, etc. At the same time, accompanied by high-energy electron and ion bombardment, 200-280nm short-wave ultraviolet radiation, and alternating strong electric field, multiple physicochemical effects are achieved to remove the cell walls and cell membranes of residual stubborn mold spores and bacterial spores, destroy intracellular functional proteins and genetic material, and prevent microbial repair and regeneration.

[0030] In some embodiments, a flexible sealing curtain is provided at the opening on the side wall of the second sterilization chamber through which the transmission unit 4 passes, so as to isolate the atmosphere inside the second sterilization chamber from the outside. The first gas control unit includes a second air inlet and a second air outlet disposed opposite to each other on the inner wall of the first sterilization chamber 11. The second air inlet is used to introduce dry air, nitrogen or nitrogen-air mixture into the second sterilization chamber, and the second air outlet is used to discharge the gas inside the second sterilization chamber, so that the second sterilization chamber is in a dry air, nitrogen or nitrogen-air mixture atmosphere.

[0031] In some embodiments, the cold plasma generator 21 is a dielectric barrier discharge (DBD) plasma generator, which includes multiple processing heads 211. Each processing head 211 is disposed within the second sterilization chamber via a movable part. Each movable part can change the position and orientation of its corresponding processing head 211 within the second sterilization chamber, so that the processing head 211 can discharge towards the peeled nuts located within the second sterilization chamber, thereby improving the uniformity of the effect within the second sterilization chamber. In some embodiments, the movable part includes a linear slide arranged perpendicular to the material conveying direction, so that the processing head 211 can move along the perpendicular to the material conveying direction, increasing the effective range of the processing head 211. In some embodiments, multiple sets of processing heads 211 are arranged at the top of the second sterilization chamber along the material conveying direction. Each set contains four processing heads 211. The four processing heads 211 belonging to the same set are arranged perpendicular to the material conveying direction, with the two middle processing heads 211 arranged vertically downwards and the two outer processing heads 211 arranged inclined towards the center to cover the top and sides of the peeled nuts.

[0032] In some embodiments, the preservation unit 3 includes a preservation cavity, in which a second gas control unit is provided. The second gas control unit is used to store the peeled nuts in the preservation cavity under an inert gas atmosphere. The inert gas can quickly replace the oxygen and water vapor in the gaps between materials and in the packaging cavity, completely isolating the contact channels between the nut oil and oxygen, inhibiting the oxidation and rancidity of unsaturated fatty acids from the source, and inhibiting the revival and reproduction of residual trace aerobic microorganisms and mold spores, solidifying the results of the first two stages of sterilization and detoxification, and preventing secondary pollution and mold recurrence after sterilization.

[0033] In some embodiments, the preservation cavity is enclosed by a second vertical box 31. Multiple layers of second guide rails are provided on the inner side wall of the second vertical box 31 to support multiple stacked second trays 32. One side of the second vertical box 31 is open to facilitate the placement and removal of the second trays 32. The second gas control unit includes a third air inlet at the bottom of the second vertical box 31 and a third air outlet at the top of the second vertical box 31. The third air inlet is used to introduce inert gas into the preservation cavity, and the third air outlet is used to discharge the gas in the preservation cavity. The bottom air inlet and top air outlet make the gas in the preservation cavity flow in one direction to discharge the air in the preservation cavity and keep the peeled nuts in the preservation cavity in an inert gas atmosphere.

[0034] In other embodiments, the first sterilization chamber 11 is enclosed by a second storage silo, in which the peeled nuts are piled. A second inlet is provided at the top of the storage silo, and a second outlet is provided at the bottom of the storage silo. The second gas control unit includes a third air inlet for conveying inert gas and a third air outlet for discharging gas from the storage silo, which are provided on the inner wall of the storage silo, so that the peeled nuts can be in an inert gas atmosphere.

[0035] In some embodiments, the conveying unit 4 includes a conveyor belt 41, and the nut sterilization and preservation device further includes a uniform conveying unit 5. The uniform conveying unit 5 includes a vibrator, a uniform scraper, and a guide plate. The vibrator is fixedly mounted on the conveyor belt 41 to apply reciprocating vibration to the peeled nuts on the conveyor belt 41. The uniform scraper is located on the top of the conveyor belt 41 between the discharge port of the first sterilization chamber 11 and the second sterilization unit 2. There is a gap between the bottom edge of the uniform scraper and the conveyor belt 41. The gap can be adjusted so that the gap is between the thickness of a single layer of peeled nuts and the thickness of a double layer of peeled nuts. The guide plates are respectively mounted on both sides of the conveyor belt 41 to prevent the peeled nuts on the conveyor belt 41 from overflowing from both sides of the conveyor belt 41. By applying small-amplitude high-frequency reciprocating vibration to the peeled nuts on the conveyor belt 41 through the vibrator and the scraping action of the uniform scraper, the peeled nuts on the conveyor belt 41 are spread flat on the upper surface of the conveyor belt 41 so that they can be fully sterilized when passing through the second sterilization unit 2.

[0036] In some embodiments, the first tray 12 and the second tray 32 are interchangeable. A robotic arm is provided at the opening of the first vertical housing 13. After the peeled nuts inside the first sterilization chamber 11 are sterilized by ultraviolet-ozone, the robotic arm sequentially pulls out each of the first trays 12 and places them on the conveyor belt 41 located at the first end of the transmission unit 4. The first trays 12 are sequentially transported through the second sterilization unit 2 to the second end of the transmission unit 4 via the conveyor belt 41. A robotic arm is also provided at the opening of the second vertical housing 31. The robotic arm removes each of the first trays 12 from the conveyor belt 41 and stacks them in the second vertical housing 31. In some embodiments, the transmission unit 4 includes conveyor belts 41 respectively arranged on both sides along the material conveying direction. The first trays 12 are placed between the two conveyor belts 41. The processing heads 211 of the cold plasma generator 21 are evenly distributed along the axial direction of the transmission unit 4. Since the first trays 12 have multiple first holes, the processing heads 211 can also cover the bottom surface of the peeled nuts. In some embodiments, a uniform conveying unit 5 is disposed between the transmission unit 4 and the first sterilization unit 1. The uniform conveying unit 5 includes a vibration motor, a vibration support 51, and a vibration tray 52. ​​The output end of the vibration motor is connected to the bottom end of the vibration support 51, and the vibration tray 52 is disposed at the top end of the vibration support 51. The first trays 12 are sequentially pulled out and placed on the vibration tray 52 by a robotic arm disposed at the opening of the first vertical box 13. By applying small-amplitude, high-frequency reciprocating vibration to the peeled nuts on the first trays 12, the peeled nuts are spread flat on the upper surface of the first trays 12. Then, the first trays 12 are placed on the conveyor belt 41 located at the first end of the transmission unit 4 by the robotic arm disposed at the opening of the first vertical box 13.

[0037] In some embodiments, the nut sterilization and preservation device also includes a sealed box 6, in which the first sterilization unit 1, the second sterilization unit 2, the preservation unit 3, and the transmission unit 4 are all disposed. An entrance and exit are provided on the side of the sealed box 6, and an entrance and exit door is installed at the entrance and exit to open or close the entrance and exit. The sealed box 6 isolates the first sterilization unit 1, the second sterilization unit 2, and the preservation unit 3 from the outside world, so that each sterilization unit and the preservation unit 3 can work in their respective required atmosphere.

[0038] In some embodiments, a controller, power supply and air supply system are also provided outside the enclosed box 6 to maintain the normal operation of the first sterilization unit 1, the second sterilization unit 2, the preservation unit 3 and the transmission unit 4.

[0039] Example 2 This embodiment provides a method for sterilizing and preserving nuts, using the nut sterilization and preservation device in Embodiment 1, including the following steps: The peeled nuts are placed in the first sterilization unit 1, where ozone-ultraviolet sterilization is performed. Specifically, ultraviolet light irradiation destroys the bacterial DNA on the nut surface, rapidly reducing the number of viable bacteria on the surface. Ozone penetrates the nut folds, kernel gaps, and seed coat micropores, eliminating ultraviolet light irradiation dead zones, effectively inactivating bacterial vegetative cells and surface mold. At the same time, it destroys the protective layer of mold biofilm, weakens the resistance of stubborn microbial spores, and improves the uniformity of irradiation of the peeled nuts on the first tray 12 through the first hole opened on the first tray 12. The robotic arm installed at the opening of the first vertical box 13 pulls out each first tray 12 in sequence and places it on the vibrating tray 52. ​​By applying small-amplitude high-frequency reciprocating vibration to the peeled nuts on the first tray 12, the peeled nuts are spread flat on the upper surface of the first tray 12. Then, the robotic arm installed at the opening of the first vertical box 13 places the first tray 12 on the conveyor belt 41 located at the first end of the transmission unit 4. The peeled nuts are transported to the second sterilization unit 2 via the transmission unit 4. The second sterilization unit 2 sterilizes the peeled nuts with cold plasma. The cold plasma generator 21 discharges towards the peeled nuts located in the second sterilization chamber. The first gas control unit keeps the second sterilization chamber in a dry air, nitrogen, or nitrogen-air mixture atmosphere. The high-energy particles generated by the high-frequency high-voltage electric field physically bombard the cells and cell membranes of the residual stubborn mold spores and bacterial spores, destroying intracellular functional proteins and genetic material, and preventing microbial repair and regeneration. The peeled nuts are transported to the preservation unit 3, where they are stored in an inert gas atmosphere. Specifically, after the peeled nuts reach the second end of the transmission unit 4, the first trays 12 on the conveyor belt 41 are removed by a robotic arm and stacked in the second vertical box 31, so that the peeled nuts are stored in an inert gas atmosphere. The inert gas can quickly replace the oxygen and water vapor in the gaps between materials and the packaging cavity, completely isolating the contact channels between the nut oil and oxygen, inhibiting the oxidation and rancidity of unsaturated fatty acids from the source, and inhibiting the revival and reproduction of residual trace aerobic microorganisms and mold spores, solidifying the results of the first two stages of sterilization and detoxification, and preventing secondary pollution and mold recurrence after sterilization.

[0040] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A nut sterilization and preservation device, characterized in that: It includes a first sterilization unit, a second sterilization unit, and a preservation unit. The first sterilization unit, the second sterilization unit, and the preservation unit are arranged sequentially along the material conveying direction. The first sterilization unit is used to perform ozone-ultraviolet sterilization on the peeled nuts. The second sterilization unit is used to perform cold plasma sterilization on the peeled nuts. The preservation unit is used to store the peeled nuts in an inert gas atmosphere.

2. The nut sterilization and preservation device according to claim 1, characterized in that: The first sterilization unit includes a first sterilization chamber, in which at least one first tray is disposed. The first tray is used to hold the peeled nuts, and the peeled nuts are laid flat in the first tray. An ozone sterilization section and an ultraviolet sterilization section are disposed on the inner wall of the first sterilization chamber. The ozone sterilization section is used to expose the peeled nuts in the first sterilization chamber to an ozone atmosphere, and the ultraviolet sterilization section is used to irradiate the peeled nuts on the first tray with ultraviolet light.

3. The nut sterilization and preservation device according to claim 2, characterized in that: The first tray has a plurality of first holes, the diameter of which is smaller than the diameter of the peeled nuts. The first holes allow ultraviolet light to shine from the bottom of the first tray upwards onto the peeled nuts on the first tray.

4. The nut sterilization and preservation device according to claim 2, characterized in that: The nut sterilization and preservation device further includes a transmission unit. The first end of the transmission unit is located near the discharge port of the first sterilization chamber, and the second end of the transmission unit is located near the inlet of the preservation unit. The second sterilization unit is located in the middle of the transmission unit. The transmission unit is used to transport the peeled nuts from the first end of the transmission unit to the second end of the transmission unit.

5. The nut sterilization and preservation device according to claim 4, characterized in that: The second sterilization unit includes a second sterilization chamber, in which a cold plasma generator and a first gas control unit are disposed. The cold plasma generator is used to discharge towards the peeled nuts located in the second sterilization chamber, and the first gas control unit is used to keep the second sterilization chamber in a dry air, nitrogen, or nitrogen-air mixture atmosphere.

6. The nut sterilization and preservation device according to claim 1, characterized in that: The preservation unit includes a preservation cavity, and a second gas control unit is provided in the preservation cavity. The second gas control unit is used to store the peeled nuts located in the preservation cavity in an inert gas atmosphere.

7. The nut sterilization and preservation device according to claim 4 or 5, characterized in that: The transmission unit includes a conveyor belt, and the nut sterilization and preservation device further includes a uniform conveying unit. The uniform conveying unit includes a vibrator, a uniform scraper, and a guide plate. The vibrator is fixedly mounted on the conveyor belt to apply reciprocating vibration to the peeled nuts on the conveyor belt. The uniform scraper is disposed on the top of the conveyor belt located between the discharge port of the first sterilization chamber and the second sterilization unit. There is a gap between the bottom edge of the uniform scraper and the conveyor belt. The gap is adjustable so that it is between the thickness of a single layer of peeled nuts and the thickness of a double layer of peeled nuts. The guide plates are respectively disposed on both sides of the conveyor belt to prevent the peeled nuts on the conveyor belt from overflowing from both sides of the conveyor belt.

8. The nut sterilization and preservation device according to claim 5, characterized in that: The cold plasma generator is a dielectric barrier discharge plasma generator, which includes multiple processing heads. Each processing head is disposed in the second sterilization chamber via a movable part. Each movable part can change the position and orientation of its corresponding processing head in the second sterilization chamber, so that the processing head can discharge towards the peeled nuts located in the second sterilization chamber.

9. The nut sterilization and preservation device according to claim 4 or 5, characterized in that: The nut sterilization and preservation device also includes a closed box, in which the first sterilization unit, the second sterilization unit, the preservation unit and the transmission unit are all disposed. An entrance and exit are provided on the side of the closed box, and an access door capable of opening or closing the entrance and exit is installed at the entrance and exit.

10. A method for sterilizing and preserving nuts, characterized in that: The nut sterilization and preservation device according to any one of claims 1 to 9 includes the following steps: The peeled nuts are placed in the first sterilization unit, and the peeled nuts are sterilized by ozone-ultraviolet sterilization through the first sterilization unit; The peeled nuts are conveyed to the second sterilization unit, where they are sterilized by cold plasma. The peeled nuts are transported to the preservation unit, where they are stored in an inert gas atmosphere.

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