Moisture-proof packaging method for lychee crisp transportation

Abstract

This invention relates to the field of food packaging and transportation preservation technology, and discloses a moisture-proof packaging method for transporting lychee cakes. The method includes: placing the lychee cakes in a biodegradable inner tray, sequentially subjecting them to ozone sterilization and drying inert gas blowing in a sealed chamber, transferring the product and inner tray as a whole to a low-temperature, low-humidity environment, dehydrating them, placing them in a biodegradable packaging bag, vacuuming the packaging bag, filling it with a drying protective gas containing a slow-release antibacterial agent, sealing it to form a primary packaging unit, arranging the primary packaging units inside a transport outer box lined with biodegradable padding, filling the gaps with functional cushioning filler made from packaging scraps, and finally sealing the outer box and printing a composite identification code containing instructions for ecological treatment and recycling. This invention systematically solves the problems of lychee cakes easily absorbing moisture and becoming moldy, and high transportation losses, while simultaneously achieving full biodegradability and recycling of packaging materials.

Description

Technical Field

[0001] This invention relates to the field of food packaging and transportation preservation technology, and in particular to a moisture-proof packaging method for transporting lychee cakes. Background Technology

[0002] Lychee cakes are rich in sugar, oil, and moisture. During storage and transportation, they are prone to problems such as softening due to moisture absorption, flavor deterioration, microbial growth, and even mold due to the intrusion of environmental moisture. Especially in medium and long-distance logistics, temperature and humidity fluctuations and transportation compression are frequent, and traditional packaging cannot provide stable and reliable moisture protection and physical protection.

[0003] Common moisture-proof packaging methods often rely on single technologies, such as simple sealing with plastic inner trays and composite film bags, or placing individual desiccant packets inside the box. These methods have significant shortcomings: First, plastic packaging is non-degradable, which contradicts the requirements of environmental sustainability; second, desiccant packets are prone to displacement or become ineffective after absorbing moisture, and cannot inhibit the growth of microorganisms caused by residual oxygen inside the packaging; third, the packaging components are functionally isolated, with components for cushioning, moisture protection, and antibacterial purposes being fragmented and lacking system integration, making it difficult to cope with the comprehensive challenges of complex transportation environments.

[0004] Existing packaging technologies lack the ability to proactively manage and intelligently monitor the internal microenvironment of the packaging system. Scrap materials generated during the packaging process are mostly treated as waste rather than recycled. Furthermore, whether the packaging has failed during transportation and whether the product quality is safe can only be determined by fixed expiration date labels or by post-construction inspection, resulting in delayed and unreliable information.

[0005] Based on the aforementioned industry pain points and technological gaps, the industry urgently needs a system that not only pursues short-term moisture-proof and freshness-preserving effects, but also focuses on building a complete lifecycle system from packaging production and transportation protection to waste disposal. This system aims to fundamentally improve the logistic adaptability and quality assurance level of lychee cake products, while responding to environmental protection policies and achieving technological upgrading of the packaging industry. Summary of the Invention

[0006] The purpose of this invention is to provide a moisture-proof packaging method for transporting lychee crisps in order to solve the problems in the prior art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a moisture-proof packaging method for transporting lychee cakes, comprising the following steps: S1, In-situ cleaning and inner tray pretreatment: The individual lychee cakes to be packaged are placed in an inner tray made of biodegradable material, and the surface is sterilized by ozone gas in a closed treatment chamber, and then replaced with dry inert gas for blowing treatment. S2, Preliminary dehydration and packaging: The pre-treated lychee cake and inner tray are transferred to a low-temperature and low-humidity environment for dehydration, and then placed into a biodegradable film packaging bag. S3, Negative pressure dry gas replacement packaging: After vacuuming the packaging bag, it is filled with a dry protective gas containing a slow-release gas antibacterial agent and sealed to form a primary packaging unit; S4, Outer Box Integration and Functional Waste Containment: A biodegradable liner made of agricultural by-products is laid inside the transport outer box. Multiple primary packaging units are arranged inside the box, and functional cushioning filler made from processed scraps generated during the packaging process is filled in the gaps between them to form an outer box integration. The functional cushioning filler provides cushioning protection while also having the functions of moisture absorption and limiting air convection. S5, Sealing and Labeling: Close and seal the outer box, generate an ecological treatment label and a composite label code for waste classification and recycling guidelines based on each biodegradable component defined by this method, and print it on the outer surface of the outer box.

[0008] The beneficial effects of the technical solution provided by this invention include at least the following: Before the packaging unit is formed, this invention systematically eliminates free moisture on the product surface, reduces the initial humidity and oxygen content inside the packaging, and fills it with a protective gas with slow-release antibacterial function. It constructs a solid preservation barrier from physical, chemical and microbiological levels, effectively inhibiting the risk of lychee cakes absorbing moisture, oxidizing and becoming rancid and moldy during transportation.

[0009] This invention creatively realizes the biodegradability of the entire chain from packaging to cushioning materials. All inner trays, packaging bags, and outer box liners that come into direct contact with the product are made of compostable bio-based materials. In particular, the clean scraps generated during the packaging process are recycled and made into biomimetic honeycomb structure fillers with directional moisture-wicking and heat-retaining cushioning functions. This realizes the material closed loop within the production system and the resource-added value of waste, thereby improving the overall efficiency and environmental friendliness of the packaging system.

[0010] This invention breaks through the passive protection mode of traditional packaging and introduces a two-level active intelligent early warning mechanism. Inside the box, the pH indicator coating on the inner surface of the liner can react with color to trace amounts of deteriorating gas caused by extreme conditions, providing an intuitive visual alarm. On the outside of the box, a smart material sensitive to the cumulative effect of time, temperature and humidity is used as a dynamic warning, and the progress of color change is correlated with the actual quality degradation of the product. This mechanism greatly improves the transparency, response speed and risk management capabilities of the supply chain.

[0011] When sealing the packaging, the method of this invention automatically generates and prints a composite identification code containing machine-readable ecological processing data and visual recycling guidance based on information of all biodegradable components used. This provides a standardized data entry point and operation guide for backend recycling and sorting, industrial composting, or household composting. Thus, this method not only achieves moisture protection for the product but also ensures that packaging waste can smoothly enter environmentally friendly disposal channels, truly promoting the implementation of the circular economy in the packaging field. Attached Figure Description

[0012] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0013] Figure 1 This is a flowchart of a method provided in an embodiment of the present invention. Detailed Implementation

[0014] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a moisture-proof packaging method for transporting lychee cakes according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0016] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0017] The following description, in conjunction with the accompanying drawings, details a specific scheme for a moisture-proof packaging method for transporting lychee crisps provided by the present invention.

[0018] Please see Figure 1 The diagram illustrates a method flowchart for a moisture-proof packaging method for transporting lychee cakes according to an embodiment of the present invention. The method includes the following steps: S1, In-situ cleaning and inner tray pretreatment: The individual lychee cakes to be packaged are placed in an inner tray made of biodegradable material, and the surface is sterilized by ozone gas in a closed treatment chamber, and then replaced with dry inert gas for blowing treatment. S2, Preliminary dehydration and packaging: The pre-treated lychee cake and inner tray are transferred to a low-temperature and low-humidity environment for dehydration, and then placed into a biodegradable film packaging bag. S3, Negative Pressure Dry Gas Replacement Packaging: After vacuuming the packaging bag, it is filled with a dry protective gas containing a slow-release gas antibacterial agent and sealed to form a primary packaging unit; S4, Outer Box Integration and Functional Waste Containment: A biodegradable liner made of agricultural by-products is laid inside the transport outer box. Multiple primary packaging units are arranged inside the box, and functional cushioning filler made from processed scraps generated during the packaging process is filled in the gaps between them to form an outer box integration. The functional cushioning filler provides cushioning protection while also having the functions of moisture absorption and limiting air convection. S5, Sealing and Labeling: Close and seal the outer box, generate an ecological treatment label and a composite label code for waste classification and recycling guidelines based on each biodegradable component defined by this method, and print it on the outer surface of the outer box.

[0019] In one embodiment of the present invention, the in-situ cleaning and inner tray pretreatment steps include: placing the lychee cake unit to be packaged in an inner tray made of biodegradable material, performing surface sterilization with ozone gas in a sealed treatment chamber, and then replacing it with dry inert gas for blowing treatment. The inner tray made of biodegradable material is placed on the conveyor device in the sealed processing room in advance. After being positioned and fixed, the individual lychee cakes to be packaged are placed one by one into the predetermined cavity of the inner tray. Close and seal the treatment chamber, introduce ozone gas at a concentration of 10-50 ppm into the chamber, and maintain the circulation treatment at room temperature for 5-15 minutes to sterilize the surface and inner tray of the lychee pastry. Ozone gas was expelled from the treatment room, and then dry nitrogen gas with a dew point below -40°C was continuously introduced to blow on the surface of the lychee cake for 2-5 minutes to replace the residual gas and remove free moisture from the surface. Stop blowing the gas, then maintain a slightly positive pressure dry inert gas environment in the treatment room and let it stand for 1-3 minutes to allow the lychee crisp monomers to reach the preset balance standard with the ambient temperature and humidity.

[0020] It should be noted that the ozone gas concentration range and treatment time are determined in combination based on the characteristics of the lychee pastry product and the tolerance of the biodegradable inner tray material. In a preferred embodiment, an ozone concentration of 30 ppm is used for cyclic treatment for 10 minutes. This combination of parameters can effectively kill microorganisms on the surface of the lychee pastry and the inner tray while minimizing the oxidative degradation of the flavor substances on the surface of the lychee pastry caused by ozone, and ensuring that the mechanical properties of the inner tray material are not significantly affected.

[0021] Dry nitrogen with a dew point below -40°C is used to quickly replace residual ozone and ambient moisture without introducing new moisture. The blowing time is set to 2-5 minutes, and the preferred blowing gas flow rate is 0.5-1.0 m / s to avoid physical damage to the product surface caused by airflow impact.

[0022] After blowing with dry nitrogen, maintain a slightly positive pressure (e.g., 50-100 Pa higher than ambient pressure) in the treatment room and let it stand for 1-3 minutes. The standing process allows trace amounts of moisture and temperature between the interior and surface of the lychee crisp monomer, as well as between the product and the inner tray contact point, to reach a new equilibrium in the dry inert atmosphere. This avoids the risk of local condensation caused by immediately entering the next packaging stage. In this embodiment, the preset equilibrium standard refers to the temperature and relative humidity readings at the monitoring points in the treatment room fluctuating by no more than ±0.5℃ and ±2% within 30 seconds.

[0023] The inner tray made of biodegradable material is preferably a cellulose-based composite material or a modified polylactic acid (PLA) material that has been thermoformed. Its pre-designed cavity is adapted to the shape of the lychee cake monomer, providing moderate support while reducing the contact area, which is conducive to gas flow and subsequent demolding. In addition, the inner tray should be dusted and basically cleaned before pretreatment.

[0024] In one embodiment of the present invention, the preliminary dehydration and packaging process includes: transferring the pretreated lychee crisps and inner tray to a low-temperature, low-humidity environment for dehydration, and then placing them into a biodegradable film packaging bag. The pre-treated lychee cakes and inner trays are transferred to a low-temperature and low-humidity treatment room through a buffer airlock. The temperature in the low-temperature and low-humidity treatment room is controlled within the range of 10-15℃ and the relative humidity is below 20%. The cakes are left to stand for 10-20 minutes. Maintain constant temperature and humidity in the low-temperature and low-humidity processing room, and continuously blow the lychee cake with low-speed circulating airflow for 5-10 minutes. Place the biodegradable film packaging bags in the ultraviolet irradiation area of ​​the same low-temperature and low-humidity treatment room and irradiate them continuously for 3-8 minutes to sterilize and remove static electricity from the packaging bags. In a low-temperature and low-humidity processing room, the lychee cake and its inner tray are placed into a biodegradable film packaging bag and initially sealed to lock in the humidity level inside the packaging bag.

[0025] It should be noted that the temperature range of 10-15℃ is significantly lower than the melting point of common oils and the critical temperature for sugar deliquescence in lychee pastries. This can effectively inhibit the seepage of internal oils and the absorption of moisture by surface sugars. At the same time, the low temperature environment can inhibit microbial activity. Combined with a low relative humidity of less than 20% (preferably controlled at 15%±3%), a water vapor partial pressure difference is established between the surface of the lychee pastry and the surrounding environment. This drives water molecules on the surface and shallow layer of the lychee pastry to diffuse slowly and evenly into the surrounding environment within 10-20 minutes, preventing the product from hardening and cracking due to rapid water loss.

[0026] In this embodiment, under constant low temperature and low humidity conditions, a low-speed circulating airflow with a wind speed of 0.3-0.8 m / s is used to continuously blow on the lychee crisps for 5-10 minutes. The airflow continuously removes the saturated thin layer of humid air from the surface of the product, improving the dehydration efficiency. In addition, blowing is also used to avoid uneven dehydration of products in different positions in the processing room due to position differences. The blowing airflow direction should be set from top to bottom or horizontal circulation to avoid direct blowing causing product displacement or surface powder to fall off.

[0027] In this embodiment, the biodegradable film packaging bag is placed in the ultraviolet irradiation area of ​​the same treatment room, using a wavelength of 253.7nm and an intensity of not less than 30μW / cm. 2 Irradiation with UVC light source for 3-8 minutes can effectively destroy the DNA / RNA of microorganisms. The ions generated by its ionization of the air neutralize the static electricity accumulated in the biodegradable film during production and cutting, reducing the risk of dust or microorganisms adsorbed by static electricity during subsequent filling and sealing of the packaging bag.

[0028] In this embodiment, the bagging is completed in the same low-temperature and low-humidity processing room, and low-temperature heat sealing or pressure sealing is used (only 80-90% of the bag opening length is sealed, leaving a small section for subsequent vacuuming channel) to avoid exposing the dehydrated product to the relatively high humidity environment of the transfer channel and to prevent the product from becoming damp again before entering the next packaging step.

[0029] In one embodiment of the present invention, the negative pressure dry gas replacement packaging step, which involves evacuating the packaging bag, filling it with a dry protective gas containing a slow-release gaseous antibacterial agent, and sealing it to form a primary packaging unit, includes: The packaging bag containing the lychee cakes and inner tray is heat-sealed on all sides except the opening to form a semi-sealed bag. Connect the bag opening to the vacuum system and evacuate the bag to a pressure of -0.08 MPa within 10-15 seconds. Then fill the bag with dry nitrogen to a pressure of -0.04 MPa and maintain this pressure for 5-10 seconds. Continue to evacuate the bag to a pressure of -0.095 MPa within 5-8 seconds, and then fill the bag with a pre-concentrated dry protective gas containing a slow-release gaseous antibacterial agent until the pressure inside the bag is -0.03 MPa. After inflation, keep the bag opening open for 1-3 seconds, then heat seal the side where the bag opening is located to form a primary packaging unit. Cut and recycle any excess bag material.

[0030] It should be noted that, in this embodiment, the synergistic effect of the two-step vacuuming and inert gas replacement includes: First, the main purpose of pumping to -0.08MPa and then filling with dry nitrogen to -0.04MPa is to quickly remove most of the air (especially oxygen and residual moisture) inside the bag through large-volume gas replacement, and maintain this for 5-10 seconds to ensure that the nitrogen diffuses fully inside the bag. The second step, evacuating to -0.095MPa, aims to remove the mixture of nitrogen gas initially introduced and any trace amounts of air that may remain. This creates an initial environment for the subsequent precise filling of functional protective gas, maintaining a slight negative pressure state to ensure the packaging bag fits tightly to the contents. This reduces the internal gas volume and convection while maintaining the stability of the bag structure, preventing excessive expansion or contraction of the bag due to external air pressure fluctuations or transportation bumps.

[0031] In this embodiment, a drying protective gas containing a slow-release gaseous antibacterial agent is used. The antibacterial agent is preferably a food-grade chlorine dioxide gas slow-release agent or plant essential oil microcapsules (such as thymol or carvacrol). After the gas is introduced, it can continuously and in low doses release the active ingredients from the slow-release carrier during the product's shelf life, forming and maintaining an antibacterial micro-atmosphere in the internal space of the packaging. Its concentration needs to be controlled to ensure effective antibacterial action and compliance with food safety standards, while not adversely affecting the flavor and color of the lychee pastry.

[0032] When the inflation process ends, the gas composition near the inflation pipeline port may have a slight difference from the set protective gas concentration. Briefly opening the bag opening allows for a limited exchange of gas between the bag and the external processing chamber, which is used to expel any non-protective gases that may be present at the bag opening and to balance the gas pressure inside the bag with the pressure in the environmental processing chamber, providing a stable pressure interface for subsequent heat sealing operations.

[0033] In this embodiment, the excess bag material cut and recycled after heat sealing of the bag opening is used as clean scraps, which can be collected and used in the subsequent manufacturing of the functional cushioning filler in the claims, thus realizing the closed-loop utilization of materials within the same packaging system.

[0034] In one embodiment of the present invention, the outer casing integration and functional waste containment include the following steps: laying a biodegradable liner made of agricultural by-products inside the transport outer casing, arranging multiple primary packaging units inside the casing, and filling the gaps between them with functional cushioning filler made from processed scraps generated during the packaging process, thus forming the outer casing integration body. According to the inner wall dimensions of the outer shipping container, the biodegradable liner made of agricultural by-products is cut and tightly laid on the bottom and four inner side walls of the outer container. Multiple primary packaging units are arranged in a row and column matrix on the inner lining of the outer carton, with uniform gaps between each unit. The functional buffer filler is evenly filled into the gaps reserved between each primary packaging unit, and the filling height is controlled to be flush with the top of the primary packaging unit. Above all the primary packaging units and functional cushioning fillers, a biodegradable liner is placed as the top layer of isolation. It is then gently pressed to adhere to the underlying material, forming the outer box assembly.

[0035] It should be noted that the biodegradable liner made from agricultural by-products is preferably made from bagasse pulp board, straw fiber felt, or modified starch-based composite material, with a thickness of 2-5 mm. It is used to prevent the primary packaging unit from directly rubbing and colliding with the rigid outer box (such as corrugated cardboard box) during transportation. In addition, the liner has moisture-absorbing and cushioning properties, and can preferentially absorb the small amount of ambient moisture that may pass through the outer box or condense along the box wall, providing the first moisture barrier for the contents. After the liner is cut, it is laid tightly to reduce the air convection path inside the box and prevent the liner from shifting during handling.

[0036] The purpose of arranging the primary packaging units in a row-column matrix with uniform gaps (usually 10-30mm wide) is: (1) The regular matrix arrangement makes the load evenly distributed in the box, which is conducive to stacking and improves the overall compressive strength; (2) It creates space for subsequent filling of functional fillers. The gaps and fillers together form a distributed buffer and functional unit array, which can disperse and absorb impact and vibration energy from all directions. Its effect is better than that of filling a single buffer material.

[0037] After the functional filler is filled, a biodegradable liner is placed on top to prevent the upper filler from loosening or escaping due to vibration during transportation. The top liner should form a complete closed surface with the side walls and bottom liner to further enhance the overall integrity of isolation, moisture protection and cushioning as the inner liner protection layer.

[0038] In one embodiment of the present invention, a biodegradable liner made from agricultural by-products has a pH indicator coating on its inner surface. The pH indicator is sensitive to ammonia gas and is used to cause a color change on the inner surface of the biodegradable liner when a trace amount of ammonia gas is generated in the box due to extreme conditions, serving as a visual warning that the products in the box may deteriorate.

[0039] It should be noted that in this embodiment, based on the possibility that the proteins and amino acids of lychee crisps may undergo microbial or chemical decomposition under extreme temperature and humidity out-of-control conditions or severe packaging failure, thereby generating trace amounts of alkaline ammonia gas, the pH indicator is preferably bromothymol blue or thymol blue, which are sensitive to ammonia gas. When the concentration of ammonia gas accumulated in the box reaches the ppm level (e.g., >5ppm), the pH indicator in the coating on the inner surface of the liner reacts. The typical color change range of bromothymol blue is from pH 6.0 (yellow) to pH 7.6 (blue). It appears green in the initial neutral environment of the liner. After contact with ammonia gas (alkaline), the local pH increases, and the coating color will irreversibly change from green / yellow-green to blue, providing an intuitive visual alarm. The pH indicator coating is applied to the inner surface of the pad using environmentally friendly water-based ink printing or spraying processes to form a thin film with a thickness of micrometers. The coating formulation must include a film-forming agent and a UV stabilizer to prevent the coating from peeling off or migrating and contaminating the product, as well as to prevent the coating from deteriorating or discoloring prematurely due to light exposure during storage. The coating pattern can be designed as a grid, stripe, or specific icon to enhance visual recognition.

[0040] The following conditions must be met to trigger this early warning mechanism: (1) The sealing of the primary packaging unit has been severely compromised, causing the gas generated by the deterioration of the internal product to escape; (2) The moisture absorption and flow restriction functions of the functional buffer packing inside the box are no longer sufficient to absorb or block the deterioration signal; Therefore, this color-changing warning is highly indicative of an accident, usually meaning that there has been a serious problem with the multi-layered protection of the packaging system, and the product has most likely undergone irreversible deterioration (such as mold or rancidity). It needs to be isolated and inspected immediately to prevent the problematic product from flowing downstream or contaminating other goods in the same box.

[0041] To facilitate identification by non-professionals, a brief illustrative explanation of this warning function can be added next to the composite identification code on the outer box, such as: "If the inner lining turns blue, do not open the box and consume directly, and contact the quality inspection department." This makes the warning information easy for warehouse managers, logistics personnel, or retailers to find intuitively and take the correct action based on the instructions.

[0042] As one embodiment of the present invention, the functional buffer filler is a biomimetic honeycomb structure unit with directional moisture conduction and heat storage buffering function. It is mainly made by crushing the biodegradable material scraps generated in steps S1 to S3, mixing them with food-grade phase change material and moisture-absorbing salt in a predetermined ratio, and then molding them. The biomimetic honeycomb structure unit has interconnected regular channels, and the inner wall of the channel has a hydrophilic gradient from the outside to the inside. During filling, the main directional direction of the channel of the unit is arranged perpendicular to the main moisture direction of the outer container of the transport.

[0043] It should be noted that, in a preferred embodiment, the mixture used to prepare the functional buffer filler (hereinafter referred to as the raw material) comprises, on a dry weight basis: (1) 60-75% of the crushed biodegradable material scraps are used as structural framework and biomass carrier; (2) 15-25% food-grade phase change material (such as paraffin hydrocarbons or fatty acid esters), with the phase change temperature set at 20-30℃ to buffer against common high temperatures during transportation; (3) 5-15% hygroscopic salts (such as calcium chloride or silica gel); The above three materials are mixed and granulated to obtain raw material particles with uniform distribution of each component. Then, they are molded into a biomimetic honeycomb structure. The interconnected regular channels are preferably a regular hexagonal honeycomb structure. This structure provides an extremely high specific surface area and a regular stress transmission path per unit volume, thus possessing both excellent compression buffering and material transport performance. The hydrophilic gradient of the inner wall of the pores is achieved by gradient surface treatment of the raw material particles, so that the outer layer of the functional buffer filler is coated with a higher proportion of hydrophilic agent (such as food-grade polyethylene glycol), while the inner layer of particles is coated with a lower proportion. When ambient moisture enters from the box wall and comes into contact with the outer surface of the filler, it is first captured by the highly hydrophilic pore inlet and then transported to the low hydrophilic region inside by capillary force. Finally, it is locked by the hygroscopic salt deep inside, thus preventing moisture from accumulating at the interface of the filler or product.

[0044] The main directions of moisture absorption for transport outer containers typically refer to: the vertical direction (the bottom may be under pressure due to stacking, and the top may come into contact with a condensing environment) and the lateral direction (the side walls may come into contact with damp walls or be exposed to rain). Arranging the main guide (i.e., the channel axis) of the honeycomb channels in a horizontal direction has the following effects: (1) When moisture enters from the top or bottom of the box, the horizontal channels provide the largest lateral diffusion area and the shortest entry depth, which can quickly guide it into the interior of the packing. (2) It makes the packing perform better when subjected to vertical stacking pressure because the honeycomb structure has the best compressive strength in the direction perpendicular to the axial direction of the channel. (3) Effectively blocks and disrupts the natural vertical air convection that may occur inside the chamber, further stabilizing the microenvironment inside the chamber.

[0045] The core raw material of the functional cushioning filler is the biodegradable material scraps generated during the packaging process of lychee cakes. This realizes the closed loop and value-added utilization of materials within the production system. By adjusting the type and proportion of phase change materials, the filler can be customized to meet the transportation needs of different climate zones. In addition, the cushioning strength and weight can be balanced by adjusting the size and wall thickness of the honeycomb cells. After the transportation task is completed, the filler can be composted together with the liner, outer box, etc. to achieve green recycling.

[0046] In one embodiment of the present invention, the steps of sealing and labeling include: closing and sealing the outer box, generating a composite identification code based on the various biodegradable components defined by this method, and printing it on the outer surface of the outer box. Close the outer box lid and apply 5-10 N / cm to the box using sealing equipment. 2 Positive pressure is applied to further compact the integrated structure of the outer casing and to structurally seal and bond all the seams of the outer casing lids. Based on the type, weight, and recycling method of all biodegradable materials used in this batch of packaging, structured eco-processing data is generated and compiled into machine-readable eco-processing identifiers. The eco-friendly treatment label is combined with a waste sorting and recycling guide that includes illustrations and text instructions to form a composite identification code, which is then printed on the outer surface of the outer box.

[0047] It should be noted that a sealing device is used to apply 5-10 N / cm to the enclosure. 2 The positive pressure (preferably 7.5 N / cm) 2 Compaction causes slight elastic deformation of the biodegradable liner and filler, making the outer box assembly more tightly bonded. This improves the outer box's resistance to pressure and deformation during stacking and transportation, and ensures that the moisture-wicking surface of the functional cushioning filler is in full contact with the primary packaging unit and liner, maximizing its humidity management and flow restriction effects.

[0048] Structured sealing refers to sealing all seams of the box lid with bio-based tape or water-active paper tape with specific textures or reinforcements to prevent edge lifting and cracking in humid or frictional environments, and can also serve as simple evidence of tamper-evident seals.

[0049] The structured ecological processing data generated based on all the biodegradable materials used in this batch of packaging comes from the Production Management System (MES) and includes, but is not limited to: the chemical names of the materials of each component (inner tray, packaging bag, liner, cushioning filler, tape), the total weight of a single outer box, the recommended industrial composting standard number or household composting certification mark, and the corresponding recycling code. This data is compiled into machine-readable identifiers, preferably QR codes, which can be quickly read by standard scanning equipment, providing a precise automated data entry point for subsequent recycling and sorting, carbon footprint accounting, or waste management.

[0050] When printing composite identification codes on the outer surface of the outer box, it is preferable to use water-based soybean ink or UV-cured bio-based ink to ensure consistent eco-compatibility throughout the packaging. The identification should be placed on at least two adjacent prominent surfaces of the box to ensure easy discovery and scanning under various stacking and handling conditions.

[0051] In one embodiment of the present invention, the composite identification code includes a dynamic warning area, which is composed of a smart material that is sensitive to the cumulative effect of time-temperature-humidity. The response threshold of the smart material is preset according to the dehydration endpoint parameter recorded in step S2 and the gas filling parameter recorded in step S3, so that the color change progress of the dynamic warning area is associated with the predicted shelf life of the primary packaging unit.

[0052] It should be noted that, in this embodiment, the smart material sensitive to the cumulative effect of time-temperature-humidity is preferably a controlled reaction system based on a dye precursor in a polymer matrix. Specifically, it is implemented by encapsulating an organic acid precursor (such as ethyl lactate) sensitive to water vapor and temperature and a pH-sensitive dye (such as bromocresol green) together in a hydrolyzable microcapsule or dispersing them in a hydrophilic polymer (such as hydroxypropyl methylcellulose) film. This smart material is sensitive to the cumulative effect of time-temperature-humidity (TTH). Its response principle is as follows: water vapor in the environment slowly penetrates and triggers the hydrolysis reaction of acid precursors under the synergistic effect of ambient temperature, gradually releasing acidic protons, causing the surrounding pH value to drop, thereby triggering a gradual and irreversible color change of the dye from basic to acidic color. The reaction rate follows the Arrhenius equation and is positively correlated with temperature and humidity.

[0053] In this embodiment, the preset response threshold of the smart material includes the following steps: (1) Record the dehydration endpoint parameters of the lychee crisp body after step S2, including the measured moisture content (%) and the initial relative humidity (%) inside the packaging bag, and record the gas filling parameters of the protective gas in step S3, including the measured dew point temperature (°C) and the initial concentration D (mg / L) of the antibacterial agent. (2) Based on the product microbial growth and chemical change kinetic model, combined with the dehydration endpoint parameters, gas filling parameters and the barrier data of the packaging film, the theoretical predicted shelf life of this batch of products is calculated. (3) Based on the predicted shelf life and the intrinsic reaction rate of the selected smart material under the reference temperature and humidity conditions, the time for the color change to the preset endpoint state is calibrated to about the shelf life days by adjusting the reactant concentration in the smart material coating or the permeability of the barrier layer.

[0054] Dynamic warning areas are typically designed as a gradient color band or a gradually filling ring, printed on the outer box as part of a composite identification code. The progress of the color change is used to visually reflect the accumulated TTH (Total Time to Shelf Life). For example, the color band gradually changes from a safe color (such as green) to a warning color (such as yellow) from left to right (or the ring from the outside to the inside), and finally to an expired color (such as orange / red). Users can quickly determine the product's shelf life stage by comparing the current color with the preset warning endpoint color mark. This warning method is based directly on environmental history rather than a fixed date, and can more realistically reflect the actual quality degradation caused by fluctuations in logistics or storage conditions.

[0055] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for moisture-proof packaging of lychee cakes for transportation, characterized in that, The method includes: S1, In-situ cleaning and inner tray pretreatment: The individual lychee cakes to be packaged are placed in an inner tray made of biodegradable material, and the surface is sterilized by ozone gas in a closed treatment chamber, and then replaced with dry inert gas for blowing treatment. S2, Preliminary dehydration and packaging: The pre-treated lychee cake and inner tray are transferred to a low-temperature and low-humidity environment for dehydration, and then placed into a biodegradable film packaging bag. S3, Negative pressure dry gas replacement packaging: After vacuuming the packaging bag, it is filled with a dry protective gas containing a slow-release gas antibacterial agent and sealed to form a primary packaging unit; S4, Outer Box Integration and Functional Waste Containment: A biodegradable liner made of agricultural by-products is laid inside the transport outer box. Multiple primary packaging units are arranged inside the box, and functional cushioning filler made from processed scraps generated during the packaging process is filled in the gaps between them to form an outer box integration. The functional cushioning filler provides cushioning protection while also having the functions of moisture absorption and limiting air convection. S5, Sealing and Labeling: Close and seal the outer box, generate an ecological treatment label and a composite label code for waste classification and recycling guidelines based on each biodegradable component defined by this method, and print it on the outer surface of the outer box.

2. The moisture-proof packaging method for transporting lychee cakes according to claim 1, characterized in that: The in-situ cleaning and inner tray pretreatment process includes: placing the individual lychee cakes to be packaged in an inner tray made of biodegradable material, performing surface sterilization with ozone gas in a sealed treatment chamber, and then replacing it with a dry inert gas for blowing treatment. The inner tray made of the biodegradable material is placed on the conveying device in the sealed processing chamber in advance. After being positioned and fixed, the individual lychee cakes to be packaged are placed one by one into the predetermined cavity of the inner tray. Close and seal the treatment chamber, introduce ozone gas at a concentration of 10-50 ppm into the chamber, and maintain the circulation treatment at room temperature for 5-15 minutes to sterilize the surface and inner tray of the lychee pastry. Ozone gas was expelled from the treatment room, and then dry nitrogen gas with a dew point below -40°C was continuously introduced to blow on the surface of the lychee cake for 2-5 minutes to replace the residual gas and remove free moisture from the surface. Stop blowing the gas, then maintain a slightly positive pressure dry inert gas environment in the treatment room and let it stand for 1-3 minutes to allow the lychee crisp monomers to reach the preset balance standard with the ambient temperature and humidity.

3. The moisture-proof packaging method for transporting lychee cakes according to claim 1, characterized in that: The initial dehydration and packaging process involves transferring the pre-treated lychee cakes and inner trays to a low-temperature, low-humidity environment for dehydration, followed by placing them entirely into a biodegradable film packaging bag. The pre-treated lychee cake and inner tray are transferred to a low-temperature and low-humidity treatment room through a buffer airlock. The temperature of the low-temperature and low-humidity treatment room is controlled within the range of 10-15℃ and the relative humidity is below 20%. The cake is left to stand for 10-20 minutes. Maintain the temperature and humidity in the low-temperature and low-humidity treatment room at a constant level, and continuously blow the lychee cake with a low-speed circulating airflow for 5-10 minutes. The biodegradable film packaging bag was placed in the ultraviolet irradiation area of ​​the same low-temperature and low-humidity treatment room and continuously irradiated for 3-8 minutes to sterilize and remove static electricity from the packaging bag. In the low-temperature and low-humidity treatment room, the lychee cake and inner tray are placed into the biodegradable film packaging bag and initially sealed to lock in the humidity state inside the packaging bag.

4. The moisture-proof packaging method for transporting lychee cakes according to claim 1, characterized in that: The negative pressure dry gas replacement packaging: after evacuating the packaging bag, filling it with a dry protective gas containing a slow-release gaseous antibacterial agent, and sealing it to form a primary packaging unit includes the following steps: The packaging bag containing the lychee cake and inner tray is heat-sealed on all sides except the bag opening to form a semi-sealed bag. Connect the bag opening to the vacuum system and evacuate the bag to a pressure of -0.08 MPa within 10-15 seconds. Then fill the bag with dry nitrogen to a pressure of -0.04 MPa and maintain this pressure for 5-10 seconds. Continue to evacuate the bag to a pressure of -0.095 MPa within 5-8 seconds, and then fill the bag with a pre-concentrated dry protective gas containing a slow-release gaseous antibacterial agent until the pressure inside the bag is -0.03 MPa. After inflation, keep the bag opening open for 1-3 seconds, then heat seal the side where the bag opening is located to form a primary packaging unit, and cut and recycle the excess bag material.

5. The moisture-proof packaging method for transporting lychee cakes according to claim 1, characterized in that: The outer casing integration and functional waste containment: The steps of lining the transport outer casing with a biodegradable liner made from agricultural by-products, arranging multiple primary packaging units inside the casing, and filling the gaps between them with functional cushioning filler made from processed scraps generated during the packaging process, to form the outer casing integration, include: According to the inner wall dimensions of the outer shipping box, the biodegradable liner made of agricultural by-products is cut and tightly laid on the bottom and four inner side walls of the outer box. Multiple primary packaging units are arranged in a row and column matrix on the inner lining of the outer carton, with uniform gaps reserved between each unit; The functional buffer filler is evenly filled into the gaps reserved between each primary packaging unit, and the filling height is controlled to be flush with the top of the primary packaging unit. Above all the primary packaging units and functional cushioning fillers, a layer of the aforementioned biodegradable liner is placed as a top insulating layer, and gently pressed to adhere it to the underlying material to form an integrated outer casing.

6. The moisture-proof packaging method for transporting lychee cakes according to claim 5, characterized in that: The biodegradable liner made from agricultural by-products has a pH indicator coating on its inner surface. The pH indicator is sensitive to ammonia gas and is used to cause a color change on the inner surface of the biodegradable liner when trace amounts of ammonia are generated in the box due to extreme conditions, serving as a visual warning that the products in the box may be deteriorating.

7. The moisture-proof packaging method for transporting lychee cakes according to claim 1 or 5, characterized in that: The functional buffer filler is a biomimetic honeycomb structure unit with directional moisture conduction and heat storage buffering functions. It is mainly made by crushing the biodegradable material scraps generated in steps S1 to S3, mixing them with food-grade phase change material and hygroscopic salt in a predetermined ratio, and then molding them. The biomimetic honeycomb structure unit has interconnected regular channels, and the inner wall of the channel has a hydrophilic gradient from the outside to the inside. During filling, the main directional direction of the channel of the unit is arranged perpendicular to the main moisture direction of the outer container of the transport.

8. The moisture-proof packaging method for transporting lychee cakes according to claim 1, characterized in that: The sealing and labeling process involves closing and sealing the outer box, generating a composite identification code based on the biodegradable components defined in this method, and printing it on the outer surface of the outer box. Close the outer box lid and apply 5-10 N / cm to the box using sealing equipment. 2 Positive pressure is applied to further compact the integrated structure of the outer casing and to structurally seal and bond all the seams of the outer casing lids. Based on the type, weight, and recycling method of all biodegradable materials used in this batch of packaging, structured eco-processing data is generated and compiled into machine-readable eco-processing identifiers. The ecological treatment label is combined with the waste classification and recycling guide containing illustrations and text to form a composite identification code, which is then printed on the outer surface of the outer box.

9. The moisture-proof packaging method for transporting lychee cakes according to claim 1, characterized in that: The composite identification code includes a dynamic warning area, which is made of a smart material that is sensitive to the cumulative effect of time, temperature and humidity. The response threshold of the smart material is preset according to the dehydration endpoint parameter recorded in step S2 and the gas filling parameter recorded in step S3, so that the color change progress of the dynamic warning area is associated with the predicted shelf life of the primary packaging unit.

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