A method for making a specimen of a heavy-shelled crab after the crab is decapitated

Abstract

The application discloses a kind of heavy shell crab unshelling shell specimen's production method, belong to aquatic animal specimen preparation technical field.The application is through raw material pretreatment, surface activation, pre-reserve tissue removal, gradient degreasing and dehydrating, composite preservation, filling and shaping, temperature control and dry, sealed color fixing and nitrogen sealing etc., specially adapt to the double-layer structure and high grease characteristics of heavy shell crab unshelling shell.The application can fully retain the natural form of crab shell, double-layer texture and color, effectively prevent cracking, delamination, mold, discoloration and oil exosmosis, the preservation period can reach more than 10 years, standardization, repeatable operation, suitable for popular science display, morphological study and craft collection.

Description

Technical Field

[0001] This invention relates to the field of aquatic animal specimen preparation technology, and in particular to a method for preparing a shell specimen of a molted crab. Background Technology

[0002] Double-shelled crabs (also known as molting crabs) are a special form of mud crabs during the intermolting period. Their naturally shed shells have unique advantages over ordinary mud crab shells, including thicker shells, clearer textures, tougher structures, and more complete shapes. Moreover, they are free from artificial damage, making them a high-quality core raw material for popular science display, biological morphology research, high-end craft collection, and the preservation of aquatic germplasm resources.

[0003] Existing crab specimen preparation techniques generally target ordinary intact crab bodies or the molted shells of ordinary mud crabs. They lack specialized processes designed for the structural characteristics of the molting shells of heavy-shelled crabs, and are characterized by low technical content and crude operation, exhibiting significant shortcomings. Poor technical targeting: The characteristics of the molting shell of the crab, namely "double-layer structure, high oil content, and tightly adhered residual tissue on the inner wall", were not taken into account. Using conventional processes can easily lead to shell delamination, cracking, and oil leakage. The operation is crude and the technology is low: there is a lack of standardized process parameters, and only simple cleaning and drying are carried out. The anti-corrosion and color preservation effects are poor and cannot meet the requirements for long-term preservation. The integrity of specimens is difficult to guarantee: Traditional processes are not designed with appropriate processing steps for the toughness of the molting shell of the crab, which can easily lead to the loss of appendages, loosening of joints, and damage to the natural form. Low resource utilization: The unique value of the molting shell of the heavy-shelled crab has not been fully explored, and the existing simple processes cannot take advantage of its thick shell and clear texture, resulting in a waste of high-quality resources.

[0004] Therefore, there is an urgent need for a specimen preparation method that is technologically advanced, highly targeted, standardized in process, controllable in operation, and can fully preserve the natural advantages of the molted shell of the crab, in order to solve the technical problems of the existing technology being crude, lacking in targeting, and having poor preservation effect. Summary of the Invention

[0005] The main objective of this invention is to provide a method for preparing shell specimens of molted crabs, thereby solving the technical problems that conventional specimen preparation processes easily lead to shell delamination, cracking, and poor preservation effects in molted crabs.

[0006] To achieve the above objectives, the present invention provides a method for preparing a shell specimen of a molted crab, comprising the following steps: Raw material pretreatment: Select crab shells that have molted naturally from the shells of the crabs with heavy shells, wash them with water and neutral detergent in sequence, and drain them to obtain pretreated crab shells; Surface activation: The pretreated crab shells are immersed in a calcium chloride solution for activation treatment to obtain activated crab shells; Residual tissue removal: Remove residual tissue from the activated crab shell to obtain a clean crab shell; Degreasing and dehydration: The cleaned crab shells are soaked in alcohol to degrease and dehydrate them, resulting in degreased and dehydrated crab shells; Preservation: The degreased and dehydrated crab shells are immersed in a preservative solution for preservation treatment, and then the remaining preservative solution on the surface of the degreased and dehydrated crab shells is removed and dried to obtain preserved crab shells; Shaping: The preservative material and degreased cotton are mixed to obtain the filling material, which is then filled into the shell and appendages of the preservative crab shell to obtain the shaped crab shell; Air-dried: The shaped crab shells are air-dried to obtain air-dried crab shells; Sealing and color fixing: The air-dried crab shells are sealed and color-fixed to obtain sealed and color-fixed crab shells; Encapsulation: The sealed and color-fixed crab shell is encapsulated to obtain a specimen.

[0007] In some embodiments of the present invention, the crab shell has a double-layer structure.

[0008] In some embodiments of the present invention, the mass concentration of the calcium chloride solution is 0.5% to 1%.

[0009] In some embodiments of the present invention, the immersion temperature for the activation treatment is 22°C to 28°C, and the immersion time is 20 min to 30 min.

[0010] In some embodiments of the present invention, the degreasing and dehydration treatment includes a first stage, a second stage, a third stage, and a fourth stage; The alcohol concentration in the first stage is 50%, the degreasing and dehydration temperature is 20℃~22℃, and the soaking time is 4h~8h. The second stage involves an alcohol concentration of 75%, a degreasing and dehydration temperature of 22℃~25℃, and a soaking time of 4h~8h. The third stage involves an alcohol concentration of 95%, a degreasing and dehydration temperature of 25℃~28℃, and a soaking time of 4h~8h. The alcohol used in the fourth stage is anhydrous ethanol, and the degreasing and dehydration temperature is 25℃~28℃, with a soaking time of 0.8h~1.5h.

[0011] In some embodiments of the present invention, the preservative solution includes formalin solution and sodium salicylate solution.

[0012] In some embodiments of the present invention, the volume concentration of formalin solution in the preservative solution is 4% to 6%, and the volume concentration of sodium salicylate solution is 4% to 6%.

[0013] In some embodiments of the present invention, the anti-corrosion material includes phenol, alum, and camphor.

[0014] In some embodiments of the present invention, after the degreased and dehydrated crab shell is soaked in a preservative solution for preservation treatment, the preservative solution is drawn out using a medical syringe and injected into the pores of the degreased and dehydrated crab shell using a multi-point injection method.

[0015] In some embodiments of the present invention, during the encapsulation step, the sealed and color-fixed crab shell is placed inside a transparent specimen box, and the specimen box is filled with nitrogen gas.

[0016] The beneficial effects that this invention can achieve are: Highly targeted: Specifically designed for the detached shells of heavy-shelled crabs, fully leveraging their unique advantages of thick shells, clear textures, and complete shapes, thus solving the problem of poor compatibility with ordinary processes; High technical controllability: The process parameters of each step are standardized and the principles are clear. The operation is controllable and repeatable, avoiding the roughness of traditional processes and improving the stability of specimen preparation quality. Complete and undamaged: No need to disassemble limbs, through precise process design, the natural shape and double-layer texture of the molted shell of the crab are 100% preserved, without cracking, delamination, or limb loss. Long-lasting corrosion protection: Adopting a triple corrosion protection strategy of gradient degreasing and dehydration + composite corrosion protection + nitrogen sealing, the specimens will not mold, be infested by insects, or rot, and the preservation period is ≥10 years, which is more than 3 times longer than traditional methods; Color retention and stability: Temperature-controlled, light-protected, and shade-free drying + professional color fixing + nitrogen oxygen barrier ensures that the specimens will not fade, yellow, or produce oil, maintaining their natural color and luster for a long time; Stable shape: Precise filling and shaping + slow air drying + stress relief ensure that the specimen does not crack or deform, the appendages are stable, and the shape is lifelike; High resource utilization rate: Fully explore the unique value of the molting shell of the crab, realize the resource utilization of high-quality resources, and have high practical value; Mass-producible: The process is standardized and the operation is controllable, making it suitable for standardized and industrialized mass production, meeting the needs of multiple fields, and possessing high promotional value. 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 description of the embodiments or the prior art are 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 the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating a method for preparing a shell specimen of a molted crab according to the present invention.

[0019] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0021] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] In this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination should be considered non-existent and not within the scope of protection claimed by this invention.

[0023] This invention provides a method for preparing a shell specimen of a molted crab, referring to... Figure 1 This includes the following steps: S10. Raw material pretreatment: Select crab shells that have molted naturally from the shells of the crabs, wash them with water and neutral detergent in sequence, and drain them to obtain pretreated crab shells. S20, Surface activation: The pretreated crab shell is immersed in a calcium chloride solution for activation treatment to obtain activated crab shell; S30. Residual tissue removal: Remove residual tissue from the activated crab shell to obtain a clean crab shell; S40, Degreasing and Dehydration: The cleaned crab shells are soaked in alcohol to undergo degreasing and dehydration treatment to obtain degreased and dehydrated crab shells; S50. Preservation: The degreased and dehydrated crab shells are immersed in a preservative solution for preservation treatment, and then the residual preservative solution on the surface of the degreased and dehydrated crab shells is removed and dried to obtain preserved crab shells. S60, Shaping: The anti-corrosion material and degreased cotton are mixed to obtain a filling material, and the filling material is filled into the shell and appendages of the anti-corrosion crab shell to obtain a shaped crab shell; S70, Air-drying: The shaped crab shells are air-dried to obtain air-dried crab shells; S80, Sealing and color fixing: The air-dried crab shells are sealed and color-fixed to obtain sealed and color-fixed crab shells; S90. Encapsulation: The sealed and color-fixed crab shell is encapsulated to obtain a specimen.

[0024] The term "double-shelled crab" refers to a special form of mud crab that occurs during the intermolt period, where a new shell has been secreted beneath the old shell, but the old shell has not yet shed. The shell obtained after natural molting is not a typical single-layer shell, but rather a double-layered structure consisting of an outer hard shell and an inner thin membrane. The outer layer is the original keratinized hard shell with clear texture and toughness, while the inner layer is a translucent, soft, thin membrane-like keratin layer. There are naturally tiny gaps between these two layers, and these gaps often contain a small amount of mucus-like body fluid and a high content of oil.

[0025] In some embodiments, the shells of naturally molted crabs are used within 24 hours of molting, provided that the shells are undamaged, free from insect infestation, have intact appendages, and are free from delamination or cracking.

[0026] In some embodiments, the crab shell has a complete double-layer structure with a gap between the two layers.

[0027] In some embodiments, the crab shell is thick with a clear double-layer texture, and the inner wall of the crab shell usually has a small amount of mucus-like residual tissue.

[0028] In some embodiments, the water used to clean the crab shells includes sterile water used to rinse off surface dust and adsorbed sea mud.

[0029] In some embodiments, the neutral detergent has a mass concentration of 3% to 5% and a pH of 7.0 to 7.5, and the neutral detergent includes dishwashing liquid.

[0030] In some embodiments, the cleaning method using a neutral detergent is as follows: The crab shells, after being washed with water, are soaked in a neutral detergent solution with a mass concentration of 3%~5% and a pH of 7.0~7.5. The soaking temperature is 20℃~25℃, and the soaking time is 10min~15min. During this time, the crevices, joints, and double-layered structure of the crab shells are brushed to remove residual mucus and impurities. Then, the shells are rinsed 3~5 times with distilled water until no foam or detergent residue remains. This embodiment, by controlling the pH value of the neutral detergent and the soaking temperature, can efficiently remove mucus-like residual tissue without damaging the surface keratin of the crab shell. Rinsing with distilled water avoids the presence of impurities from tap water, ensuring uniform penetration of the subsequent detergent solution.

[0031] In some embodiments, after rinsing with water and neutral detergent, the crab shell is placed in a ventilated place to air dry naturally until there is no free water on the surface. The drying time is controlled between 30 and 60 minutes to avoid excessive moisture loss from the shell, which may cause cracking.

[0032] Step S10 targets the double-layered structure and mucus residue of the crab shell. Through graded cleaning and precise draining, external impurities and surface mucus are removed, laying the foundation for subsequent activation, residue removal, and degreasing. This prevents impurities from clogging the shell pores and also prevents the shell from cracking due to sudden moisture loss, thus preserving its natural structural integrity.

[0033] In the surface activation step S20, calcium ions in the calcium chloride solution can undergo a complexation reaction with the chitin on the surface of the pretreated crab shell, breaking the hydrogen bonds between chitin molecules, expanding the micropores on the surface, and enhancing the structural strength of the chitin, thus adapting to the double-layer structure of the molted shell of the heavy-shell crab.

[0034] In addition, the surface activation in step S20 is carried out before the pre-reserved tissue removal in step S30 and the degreasing and dehydration in step S40. This prevents the subsequent medicine from being unable to penetrate the double-layer structure due to the thick keratin on the surface of the crab shell if it is not activated, which would result in a significant decrease in the treatment effect and problems such as incomplete preservation and oil seepage.

[0035] In some embodiments, the mass concentration of the calcium chloride solution is 0.5% to 1%, with a mass concentration error of ≤ ±0.1%. Calcium chloride solutions of this concentration can effectively utilize the ion penetration effect of calcium chloride, opening the micropores of the keratinous layer on the surface of the pretreated crab shell. This facilitates improved penetration efficiency of the solvent and preservative solution used in subsequent degreasing and dehydration processes, increasing the penetration rate by more than 30%. Simultaneously, it enhances the bonding strength of the shell's double-layer structure, preventing delamination and cracking during subsequent processing and strengthening the structural stability of the crab shell. In some embodiments, the immersion temperature for activation treatment is 22℃~28℃, and the immersion time is 20min~30min. During the immersion process, the crab shell is gently turned over every 5min to ensure that the surface of the shell and the gap between the two layers are fully in contact with the activation solution. After removal, the surface moisture is gently absorbed with sterile gauze and allowed to air dry naturally for 15min~20min.

[0036] The activated crab shell obtained after surface activation usually contains loose residual tissue inside and in the gap between the two layers, as well as mucus-like residual tissue that is tightly adhered to the crab shell.

[0037] In some embodiments, removing residual tissue from the activated crab shell includes: blowing away loose residual tissue from the activated crab shell with a high-pressure air gun and removing mucus-like residual tissue with tweezers.

[0038] In some embodiments, removing residual tissue from activated crab shells further includes immersing the activated crab shells in a trypsin solution for enzymatic hydrolysis. Trypsin can specifically degrade proteins in the residual tissue, breaking down the mucous-like residual tissue into water-soluble small molecules, which are easy to rinse away. Simultaneously, enzyme activity and hydrolysis temperature can be adjusted to avoid excessive hydrolysis that could damage the chitin structure of the shell.

[0039] In some embodiments, the enzymatic hydrolysis temperature is 25℃~30℃ and the enzymatic hydrolysis time is 3h~4h, which is conducive to promoting complete enzymatic hydrolysis.

[0040] In some embodiments, during the enzymatic hydrolysis process, the container is shaken every 1 hour to promote full contact between the trypsin and the residual tissue, thereby promoting complete enzymatic hydrolysis.

[0041] In some embodiments, after enzymatic hydrolysis, the activated crab shell is rinsed with distilled water 2-3 times and the surface moisture is naturally drained to obtain a clean crab shell.

[0042] Given the characteristics of the tightly adhered and mostly mucous residue on the inner wall of the molted shell of the crab, a dual approach of "physical blowing + enzymatic degradation" is used to thoroughly remove the residue (removal rate ≥98%), preventing the residue from rotting, molding, and smelling bad later, while avoiding damage to the natural texture of the inner shell wall.

[0043] The removal of the reserved tissue in step S30 is carried out after the surface activation in step S20 and before the degreasing and dehydration in step S40. The activated crab shell micropores are opened, which can improve the penetration efficiency of the enzymatic hydrolysate for treating the reserved tissue and ensure that the enzymatic hydrolysis is sufficient. In addition, if the degreasing and dehydration are carried out first and then the residual tissue is removed, the oil will coat the residual tissue, which will prevent the enzymatic hydrolysis from taking place and the residual tissue cannot be completely removed.

[0044] Step S40 is performed after step S30, which can prevent residual tissue from mixing with grease, thus preventing the grease from being completely removed and affecting the degreasing effect. Moreover, step S40 is performed before preservation, which can prevent grease from clogging the micropores of the crab shell, hindering the penetration of the preservative solution, resulting in incomplete preservation and the occurrence of local mold and insect infestation.

[0045] In some embodiments, dehydration and degreasing include a first stage, a second stage, a third stage, and a fourth stage.

[0046] The first stage involves soaking the cleaned crab shells in 50% alcohol for degreasing and dehydration. The temperature for this stage is 20℃~22℃, and the soaking time is 4h~8h, or 6h. This stage helps to remove the bound oil in the middle layer and the gap between the two layers of the shell.

[0047] The second stage involves soaking the cleaned crab shells, which have completed the first stage of degreasing and dehydration, in 75% alcohol for the second stage of degreasing and dehydration. The temperature for the second stage of degreasing and dehydration is 22℃~25℃, and the soaking time is 4h~8h, or 6h. This stage can remove the bound oil in the middle layer and the gap between the two layers of the shell.

[0048] The third stage involves soaking the cleaned crab shells, which have completed the degreasing and dehydration in the second stage, in 95% alcohol for further degreasing and dehydration. The temperature for the third stage is 25℃~28℃, and the soaking time is 4h~8h, or 6h. This stage is beneficial for deeply removing residual oil from the inside of the shell.

[0049] The fourth stage involves immersing the cleaned crab shells, which have completed the degreasing and dehydration in the third stage, in anhydrous ethanol for further degreasing and dehydration. The temperature for the fourth stage of degreasing and dehydration is 25℃~28℃, and the soaking time is 0.8h~1.5h, or 1h. This stage completes the dehydration process and avoids any residual moisture.

[0050] This embodiment employs gradient degreasing to gradually remove oil from different layers of the molted shell of the crab, avoiding the sudden shrinkage and cracking of the shell caused by a single application of high-concentration alcohol. Simultaneously, it thoroughly removes oil (degreasing rate ≥99%), fundamentally preventing yellowing, oiling, and mold growth in specimens after long-term preservation, thus solving the technical challenge of high oil content in the molted shell of the crab. Furthermore, the gradient alcohol concentration allows for the gradual dissolution and removal of oil, reducing osmotic pressure changes during the oil removal process and preventing cracking and delamination of the shell due to sudden osmotic pressure fluctuations. At the same time, anhydrous ethanol quickly removes residual moisture from the shell, creating conditions for subsequent penetration of the preservative solution.

[0051] In some embodiments, after each stage of soaking, degreasing, and dehydration is completed, the surface is quickly rinsed once with sterile distilled water to remove residual alcohol, and then allowed to drain naturally for 10 to 15 minutes.

[0052] After the degreasing and dehydration treatment in step S40, the micropores of the crab shell are unobstructed and free of grease. At this point, the anti-corrosion treatment in step S50 is carried out. The anti-corrosion liquid can quickly and evenly penetrate into all parts of the shell, especially the gap between the two layers. This arrangement of process steps is conducive to achieving anti-corrosion without dead angles. If the interval is too long, the micropores of the shell will shrink, resulting in insufficient penetration of the anti-corrosion liquid.

[0053] In some embodiments, the preservative solution includes formalin solution and sodium salicylate solution. Formalin has a strong bactericidal and preservative effect, which can destroy the protein structure of microorganisms and inhibit spoilage. Sodium salicylate has a synergistic preservative and antifungal effect, and can also alleviate the damage of formalin to the shell. Adjusting the pH value of the preservative solution can improve the preservative effect and prevent the shell from being corroded and discolored.

[0054] In some embodiments, the volume concentration of the formalin solution is 4% to 6%, or may be 5%, and the volume concentration of the sodium salicylate solution is 4% to 6%, or may be 5%.

[0055] In some embodiments, the volume ratio of formalin solution to sodium salicylate solution in the preservative solution is 1:1.

[0056] In some embodiments, formalin solution and sodium salicylate solution are mixed, the pH is adjusted to 6.5-7.0, and the mixture is allowed to stand for 10 minutes to remove the precipitate and obtain the preservative solution.

[0057] In some embodiments, the soaking temperature for the anti-corrosion treatment is 20℃~25℃, and the soaking time is 1.5h~2.5h, which can be 2h. During the soaking period, the crab shell is turned over once every 30 minutes to obtain degreased and dehydrated crab shells, which is conducive to the full contact of the anti-corrosion liquid with the inside of the crab shell and the gap of the double-layer structure.

[0058] In some embodiments, after the degreased and dehydrated crab shells are immersed in a preservative solution for preservation, the preservative solution is drawn up using a medical syringe and injected into the pores of the degreased and dehydrated crab shells using a multi-point injection method. These pores include the tips of appendages, the interior of chelipeds, and the gaps between the two layers. The injection volume is controlled at 0.1ml~0.2ml to facilitate the smooth entry of the preservative solution into difficult-to-penetrate areas. After completing the injection in this embodiment, the shells are continued to be immersed in the preservative solution for 30min~40min, and then the surface residual preservative solution is gently blotted dry with sterile gauze.

[0059] In some embodiments, the medical syringe has a capacity of 1 ml and a needle diameter of 0.5 mm.

[0060] The preservation process employs a composite preservative formula combined with a multi-point injection technique, which enables comprehensive preservation of the inside and outside of the shell of the crab after molting, as well as the double-layer gap. This effectively inhibits the growth of mold and insects, prevents shell decay, extends the specimen preservation period, and avoids damage to the shell's color and texture caused by the preservative solution.

[0061] The shaping in step S60 is carried out after corrosion protection, so that the corrosion protection material and the previous corrosion protection liquid work together to achieve double corrosion protection inside and outside. Moreover, if the filling is done first and then the corrosion protection is done, the filling material will block the penetration of the corrosion protection liquid, resulting in incomplete corrosion protection.

[0062] In some embodiments, the preservative material and degreased cotton are mixed and kneaded until fluffy to obtain the filling material. The filling material is then slowly filled into the shell and appendages of the preservative crab shell, and gently pressed until it is full and does not deform. During the filling process, excessive force should be avoided to prevent the shell from cracking.

[0063] In some embodiments, the anti-corrosion material includes phenol, alum, and camphor. Phenol forms a synergistic anti-corrosion effect with the pre-preservative solution, enhancing the anti-mildew and anti-insect effects. Alum can solidify upon contact with water, enhancing the shaping ability of the filler. When combined with degreased cotton, it can achieve full filling without damaging the shell.

[0064] In some embodiments, the weight ratio of phenol, alum, and camphor is 1:3:0.1.

[0065] In some embodiments, the uniformity of the mixture of phenol, alum, and camphor is ≥95%.

[0066] In some embodiments, the volume ratio of the anti-corrosion material to the degreased cotton is 3:(1~2).

[0067] In some embodiments, a support is implanted inside the appendages of the anti-corrosion crab shell, the appendages are adjusted to a naturally extended state, and the support is fixed to prevent the appendages from deforming or falling off.

[0068] In some embodiments, the support member includes wire.

[0069] The thickness of the support can be determined according to the thickness of the appendages. For example, the diameter of the support is 0.3mm to 0.8mm, which is suitable for chelipeds. For example, the diameter of the support is 0.3mm to 0.5mm, which is suitable for walking legs.

[0070] In response to the characteristics of the thick shell and large size of the crab during molting, a precisely proportioned anti-corrosion filler and thin iron wire support are used to fix the natural shape of the crab shell and appendages, preventing deformation, collapse, and appendage detachment during the air-drying process. At the same time, the filler and the previous anti-corrosion treatment form a dual anti-corrosion system to improve the anti-corrosion effect.

[0071] The air-drying process in step S70 is completed after filling and shaping but before sealing and color fixing. If the color is fixed directly without complete air-drying, the varnish will bubble and peel off, the color fixing effect will fail, and the moisture inside the shell will not be able to be discharged, making it prone to mold growth later.

[0072] In some embodiments, air drying includes: placing the shaped crab shell in a constant temperature and humidity chamber, setting the temperature to 20℃~25℃ and the relative humidity to 40%~50%, ensuring complete protection from light and ventilation, and air drying for 3~5 days. The constant temperature and humidity environment prevents the shell from expanding and contracting due to temperature and humidity fluctuations, reducing internal stress and preventing cracking; slow water loss allows moisture to be evenly removed from the shell, maintaining structural stability; and protection from light and ventilation prevents oxidation and fading of the shell's color, protecting its natural texture.

[0073] In some embodiments, the temperature control accuracy of the constant temperature and humidity chamber is ±1℃, and the humidity control accuracy is ±5%.

[0074] In some embodiments, the ventilation rate is 0.5m / s to 1m / s, and the temperature, humidity and ventilation rate are precisely controlled to allow the molting crab to lose water slowly (the water loss rate is controlled at 5%–8% per day), avoiding rapid water loss that could cause the shell to crack, delaminate, or fade, while protecting the natural texture and color of the shell surface and ensuring the specimen's morphology is lifelike.

[0075] In some embodiments, each time the moisture is removed for 10 minutes, and during the drying process, moisture is removed once a day at regular intervals. This helps to eliminate the humidity difference and stress inside and outside the crab shell, and prevent the crab shell from cracking or delaminating. In addition, the shape of the crab shell is checked once a day, and any deformation is adjusted in time.

[0076] In some embodiments, the moisture content of the air-dried crab shells obtained after air-drying is ≤10%.

[0077] S80, Sealing and color fixing: The air-dried crab shells are sealed and color-fixed to obtain color-fixed crab shells; The sealing and color-fixing treatment in step S80 is performed after the air-drying in step S70. This prevents the sealant and varnish used for sealing and color fixing from delaminating and peeling off. In addition, sealing before color fixing prevents moisture and air from entering the crab shell through gaps, which could cause the specimen to mold or fade.

[0078] In some embodiments, sealing includes: sealing the seams, cracks, appendage bases, and double-layer structure of the air-dried crab shell with sealant, and then placing it in a ventilated environment at 20°C to 25°C to air dry for 2 to 3 hours. The sealant can fill the gaps in the shell, forming a sealing barrier to prevent moisture and air from entering.

[0079] In some embodiments, the sealant includes environmentally friendly white glue with a solid content of ≥50% and a non-yellowing formula.

[0080] In some embodiments, the thickness of the sealant application is 0.05 mm to 1 mm.

[0081] In some embodiments, color fixing includes: spraying varnish onto the surface of the sealed crab shell, and then curing it for at least 24 hours in a ventilated, light-protected environment at 20°C to 25°C and relative humidity ≤50%. The varnish can form a dense protective film on the shell surface, isolating oxygen and ultraviolet rays, preventing color oxidation and fading, while enhancing the shell's gloss and protecting the surface texture.

[0082] In some embodiments, a spray gun is used to spray varnish onto the surface of the sealed crab shell, and the thickness of the spray is 0.1 mm to 0.2 mm.

[0083] In some embodiments, the spraying pressure is 0.2MPa~0.3MPa and the spraying distance is 30cm~40cm, which can avoid the phenomena of dripping and missed spraying.

[0084] In some embodiments, the cleaning process includes acrylic acid.

[0085] In some embodiments, the gloss of the varnish is 30%~50%, and the yellowing resistance grade is ≥4.

[0086] Sealing and color-fixing treatments can lock in the natural color and moisture of the crab shell, preventing oxidation and fading, as well as moisture intrusion. At the same time, they enhance the gloss of the shell surface, protect the shell texture from wear, and allow the specimen to maintain a lifelike shape and bright color for a long time.

[0087] The encapsulation step S90 serves as the final sealing step, forming a complete protection system with all the previous steps. If this step is omitted, the specimen is susceptible to oxygen and moisture, resulting in problems such as oxidation, discoloration, and mold growth, rendering all previous treatments ineffective.

[0088] In some embodiments, the encapsulation process includes: placing the sealed, color-fixed crab shell into a transparent specimen box, placing silica gel desiccant and mothballs inside the specimen box, and then filling the specimen box with nitrogen gas to displace the air. The silica gel desiccant absorbs residual moisture inside the box, preventing the specimen from becoming damp and moldy, while the mothballs provide long-lasting insect protection. These three components work synergistically to achieve ultra-long-term preservation of the specimen. Furthermore, nitrogen encapsulation technology effectively isolates the specimen from oxygen, moisture, and pests, preventing oxidation, fading, mold, and insect infestation, thus enabling ultra-long-term preservation of molted crab specimens while retaining their natural shape and color, fully utilizing the resource value of molted crab shells.

[0089] In some embodiments, the desiccant and camphor balls are placed on opposite sides of the specimen box to avoid direct contact with the specimen.

[0090] In some embodiments, the purity of nitrogen is ≥99.99%.

[0091] In some embodiments, the nitrogen purging pressure is between 0.02 MPa and 0.03 MPa.

[0092] In some embodiments, the nitrogen filling time is 1 to 2 minutes to completely replace the air in the specimen box.

[0093] In some embodiments, after filling the specimen box with nitrogen, a label is affixed to complete the encapsulation and obtain the crab shell specimen.

[0094] In some embodiments, crab shell specimens are preserved in an environment with a temperature of 18°C ​​to 25°C and a relative humidity of 35% to 50%, in a dark environment and away from corrosive gases.

[0095] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0096] Example 1 This embodiment provides a method for preparing a shell specimen of a molted crab, specifically including the following steps: S10. Raw material pretreatment: Select crab shells from crabs that have molted naturally within 12 hours. The shells should be undamaged, free from insect infestation, have intact appendages, and be free from delamination and cracking. First, rinse with running water for 3 minutes to remove surface mud and sand. Then, soak in a 3% (w / w) neutral detergent solution (pH 7.0, temperature 22℃) for 15 minutes. Gently brush the crevices and joints with a soft brush. Rinse 5 times with distilled water and let it air dry in a ventilated place for 45 minutes to obtain the pretreated crab shells.

[0097] S20. Surface activation: The pretreated crab shells are immersed in a 0.5% calcium chloride solution at a temperature of 25°C for 30 minutes, turning them over every 5 minutes. After immersion, the surface moisture is absorbed with sterile gauze and the shells are air-dried for 15 minutes to obtain activated crab shells.

[0098] S30. Removal of Pre-existing Tissue: Use a high-pressure air gun (0.5 MPa) to blow away loose residual tissue along the opening of the activated crab shell; for tightly adhered tissue, gently remove it with a blunt dissecting needle. Then immerse the crab shell in a 2% (w / w) trypsin solution and enzymatically hydrolyze it at 28°C for 3.5 hours, shaking the container every hour during this period. After enzymatic hydrolysis, rinse three times with distilled water and allow it to drain naturally to obtain a clean crab shell.

[0099] S40. Degreasing and Dehydration: Degreasing and dehydration are performed using a gradient of alcohols. First stage: Immersion in 50% alcohol at 20°C for 6 hours; Second stage: Immersion in 75% alcohol at 23°C for 6 hours; Third stage: Immersion in 95% alcohol at 26°C for 6 hours; Fourth stage: Immersion in anhydrous ethanol at 26°C for 1 hour. After each stage, the crab is quickly rinsed once with distilled water and drained for 10 minutes to obtain degreased and dehydrated crab shells.

[0100] S50. Preservation: Prepare a preservative solution by mixing 5% formalin solution and 5% sodium salicylate solution at a 1:1 ratio, and adjust the pH to 6.8. Completely immerse the degreased and dehydrated crab shells in the preservative solution at 22°C for 2 hours, turning them over every 30 minutes. Inject 0.15 ml of the preservative solution at multiple points using a 1 ml syringe (0.5 mm needle diameter) into the appendage tips and double-layered spaces. After injection, continue immersion for 30 minutes. Remove the shells and blot away any remaining solution with sterile gauze to obtain the preserved crab shells.

[0101] S60. Shaping: Mix phenol, alum, and camphor in a weight ratio of 1:3:0.1 to prepare a preservative powder, then mix it with defatted cotton in a volume ratio of 3:1 and knead until fluffy to obtain the filling material. Slowly fill the crab shell and appendages with the filling material, gently pressing until full. Insert a 0.4mm diameter wire into the walking legs and a 0.6mm diameter wire into the chelipeds, adjusting the appendages to a naturally extended state to obtain the shaped crab shell.

[0102] S70. Air Drying: Place the shaped crab shells in a constant temperature and humidity chamber, setting the temperature to 22℃, relative humidity to 45%, and ventilation rate to 0.8m / s. Keep the chamber completely dark and air dry for 4 days. Dehumidify for 10 minutes daily, checking the shape and adjusting as needed. After air drying, the moisture content of the crab shells should be ≤10%. This yields air-dried crab shells. S80, Sealing and Color Fixing: Seal the seams, appendage bases, and double-layer gaps of the air-dried crab shell with environmentally friendly white glue, applying a thickness of 0.1mm. Allow it to air dry in a ventilated environment at 22℃ for 2.5 hours. Then, spray a transparent acrylic varnish with a spray gun at a pressure of 0.25MPa, a spraying distance of 35cm, and a spray thickness of 0.15mm. Cur it at 22℃ and 45% relative humidity for 24 hours to obtain a sealed and color-fixed crab shell.

[0103] S90. Packaging: Place the sealed, color-fixed crab shell into a transparent specimen box, with two packets of silica gel desiccant (5g each) and one packet of camphor balls (1g) inside. Fill the box with 99.99% pure nitrogen gas at a pressure of 0.02MPa for 1.5 minutes to replace the air inside. After sealing, label the specimen and store it in a light-protected environment at 20℃ and 40% relative humidity.

[0104] The molted shell specimens of the crab prepared in this embodiment have complete morphology, clear double-layer texture, and natural color. According to the accelerated aging test, the preservation period can reach more than 10 years.

[0105] Example 2 This embodiment provides a method for preparing a shell specimen of a molted crab, which differs from Embodiment 1 mainly in some process parameters, specifically including: S10. Raw material pretreatment: Select crab shells within 24 hours after the natural molting of the crabs, soak them in a 5% neutral detergent solution (pH 7.2, temperature 25℃) for 10 minutes, clean them with a soft brush, rinse them three times with distilled water, and drain them for 60 minutes.

[0106] S20, Surface activation: 1% calcium chloride solution, soaking temperature 28℃, soaking time 20min.

[0107] S30. Pre-reserved tissue removal: Trypsin solution concentration 1.5%, enzymatic hydrolysis temperature 30℃, enzymatic hydrolysis time 3h, rinse twice with distilled water after enzymatic hydrolysis.

[0108] S40, Degreasing and Dehydration: First stage: 50% alcohol, temperature 22℃, soaking for 8 hours; Second stage: 75% alcohol, temperature 25℃, soaking for 8 hours; Third stage: 95% alcohol, temperature 28℃, soaking for 8 hours; Fourth stage: anhydrous ethanol, temperature 28℃, soaking for 0.8 hours.

[0109] S50, Preservative: Mix formalin solution (4% by volume) and sodium salicylate solution (4% by volume) in a 1:1 ratio. Maintain the preservative solution at 25°C and soak for 1.5 hours. Inject 0.1 ml per point, and continue soaking for 40 minutes after injection.

[0110] S60, Shaping: The anti-corrosion powder and degreased cotton are mixed in a volume ratio of 3:2. A 0.3mm diameter iron wire is inserted into the walking legs and a 0.5mm diameter iron wire is inserted into the chelicerae.

[0111] S70, Air drying: constant temperature and humidity chamber temperature 20℃, relative humidity 50%, ventilation rate 0.5m / s, air drying for 5 days.

[0112] S80, Sealing and Color Fixing: Apply sealant with a thickness of 0.05mm and allow it to dry for 3 hours; apply varnish with a thickness of 0.1mm and allow it to cure for 30 hours.

[0113] S90, Packaging: 1 pack of desiccant (5g) and 1 pack of camphor balls (1g) are built in, nitrogen filling pressure is 0.03MPa, and nitrogen filling time is 1min.

[0114] The molted shell specimens of the crab prepared in this embodiment are stable in morphology, without cracks or delamination, and retain good color, meeting the requirements for long-term preservation.

[0115] Example 3 This embodiment provides a method for preparing a shell specimen of a molted crab. The main difference between this embodiment and Embodiment 1 lies in some process parameters and operational details, specifically including: S10. Raw material pretreatment: Select crab shells within 6 hours after the natural molting of the crabs. First, use a high-pressure water gun (pressure 0.25MPa) to rinse off large dirt on the surface, then immerse in a 4% neutral detergent solution (pH 7.2, temperature 23℃), supplemented with ultrasonic cleaning (frequency 40kHz) for 5 minutes, then rinse 4 times with distilled water, and dry in a 25℃ forced-air drying oven for 15 minutes.

[0116] S20, Surface activation: 0.8% calcium chloride solution, soaking temperature 22℃, soaking time 25min.

[0117] S30. Retained Tissue Removal: First, use a vacuum cleaner with a soft brush head to remove large pieces of loose tissue. Then, use medical hemostats to hold a small cotton ball soaked in 75% alcohol and gently wipe the inner wall of the appendage. Next, immerse the crab shell in a 2.5% trypsin solution and enzymatically hydrolyze it at 25°C for 4 hours. After enzymatic hydrolysis, rinse three times with distilled water.

[0118] S40, Degreasing and Dehydration: First stage: 50% alcohol, temperature 21℃, soaking for 4 hours; Second stage: 75% alcohol, temperature 22℃, soaking for 4 hours; Third stage: 95% alcohol, temperature 25℃, soaking for 4 hours; Fourth stage: anhydrous ethanol, temperature 25℃, soaking for 1.5 hours.

[0119] S50, Preservative: Mix formalin solution (6% by volume) and sodium salicylate solution (6% by volume) in a 1:1 ratio. Maintain the preservative solution at 20°C and soak for 2.5 hours. Inject 0.2 ml per point, and continue soaking for 35 minutes after injection.

[0120] S60, Shaping: Mix the anti-corrosion powder and degreased cotton at a volume ratio of 3:1.5. Insert a 0.5mm diameter copper wire into the walking legs and a 0.8mm diameter copper wire into the chelicerae. After filling, spray a small amount of 95% alcohol to make the filler expand slightly.

[0121] S70, Air drying: constant temperature and humidity chamber temperature 25℃, relative humidity 40%, ventilation rate 1.0m / s, air drying for 3 days.

[0122] S80, Sealing and Color Fixing: Apply sealant with a thickness of 0.08mm and allow it to dry for 2 hours; apply varnish with a gloss level of 40% and a thickness of 0.2mm, and allow it to cure for 28 hours.

[0123] S90, Packaging: Includes 2 packs of desiccant (3g each) and 1 pack of camphor balls (0.8g), nitrogen filling pressure 0.025MPa, nitrogen filling time 2min, label and store in a light-protected environment at 22℃ and 45% relative humidity.

[0124] The molted shell specimens of the crab prepared in this embodiment have clear textures, bright colors, and stable appendages, making them suitable for high-end craft collections and popular science displays.

[0125] Comparative Example 1 Comparative Example 1 provides a method for preparing a shell specimen of a molted crab, which differs from Example 1 mainly in some process parameters and operational details: S40 cleans the crab shells and soaks them in anhydrous ethanol at 26°C for 1 hour to degrease and dehydrate them.

[0126] Comparative Example 2 Comparative Example 2 provides a method for preparing a shell specimen of a molted crab. The main difference from Example 1 is that no surface activation treatment is performed.

[0127] Performance testing Crab shell specimens from Examples 1 to 3 were stored in a dark environment at 22°C and 45% relative humidity. After 12 months, they were taken out to observe the preservation effects of anti-corrosion, anti-mildew, specimen color, and double-layer structure.

[0128] (1) Corrosion protection evaluation criteria: Excellent: The specimen shell shows no signs of decay, no odor, no decomposition of tissue residue, and no blackening, softening, or liquefaction at the joints of the appendages and the double-layered gaps.

[0129] Good: The specimen shell is basically free from decay, with only slight discoloration (such as light brown) in a few crevices, but there is no rot or softening, and no odor.

[0130] Acceptable: The specimen shell shows slight putrefactive spots (area <5%), with no significant odor and the putrefaction has not spread to the main parts.

[0131] Unacceptable: The specimen shows obvious signs of decay, softening, blackening, or foul odor, or the decomposition of tissue residues leads to shell damage or perforation.

[0132] (2) Anti-mildew evaluation criteria: Excellent: There is no mold growth on the surface and inside of the specimen, and no hyphae, mold spots or mold points can be observed under a magnifying glass (10×).

[0133] Good: No visible mold spots on the surface, and a very small number of scattered hyphae (area <1%) may be seen under a magnifying glass. No visible mold spots have formed.

[0134] Acceptable: A small number of visible mold spots (area <5%) are present. The mold spots are isolated, not contiguous, and do not erode the shell texture or cause discoloration.

[0135] Unacceptable: Mold area ≥5%, or mold covering the entire surface, or mold causing powdering, discoloration, or peeling of the shell surface.

[0136] (3) Specimen color evaluation criteria: Excellent: The specimen has a bright color and no obvious difference from when it was prepared. There is no yellowing, darkening, fading or whitening.

[0137] Good: The color is slightly darker or slightly yellow (color difference ΔE<3), but the overall color still retains its natural tone and there is no significant fading.

[0138] Acceptable: The color is obviously darkened or yellowed (color difference ΔE 3~6), or there is slight fading in some areas, but the color is not lost.

[0139] Unacceptable: The color is severely yellowed, blackened, or faded over a large area (color difference ΔE>6), loses its natural appearance, or white salt crystals appear.

[0140] (4) Evaluation criteria for double-layer structures: Advantages: The double-layer structure is intact, without delamination, cracking, warping, or peeling. Under a microscope, the double-layer interface is clear, continuous, and without gaps.

[0141] Good: The double-layer structure is basically intact, with occasional extremely small cracks (length <2mm, number ≤2), and no delamination, warping, or detachment.

[0142] Acceptable: The double-layer structure shows slight local delamination (length ≤ 5mm, number ≤ 3 places), or the edges are slightly raised, but the whole structure is not separated.

[0143] Unacceptable: The double-layer structure is obviously delaminated, cracked, warped or partially detached, the shell has through cracks or interlayer separation, affecting the integrity and ornamental value of the specimen.

[0144] The results are shown in Table 1 below.

[0145] Table 1

[0146] Examples 1 to 3 use the process of the present invention to prepare double-shelled crab specimens. The specimens not only retain the complete structure, but also have a good anti-corrosion effect.

[0147] Comparative Example 1 did not undergo gradient degreasing. Due to the direct treatment with high-concentration alcohol, the shell shrank rapidly, and the grease was not completely removed. Some parts showed slight yellowing and localized micro-cracks, but no serious spoilage or delamination occurred.

[0148] Comparative Example 2 was not surface activated, and the micropores of the shell were not opened. The subsequent degreasing and preservative solutions did not penetrate evenly, resulting in local grease residue, mold growth, and a significant darkening and yellowing of the color. The double-layer structure also showed delamination and warping.

[0149] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing a shell specimen of a molted crab, characterized in that, Includes the following steps: Raw material pretreatment: Select crab shells that have molted naturally from the shells of the crabs with heavy shells, wash them with water and neutral detergent in sequence, and drain them to obtain pretreated crab shells; Surface activation: The pretreated crab shells are immersed in a calcium chloride solution for activation treatment to obtain activated crab shells; Residual tissue removal: Remove residual tissue from the activated crab shell to obtain a clean crab shell; Degreasing and dehydration: The cleaned crab shells are soaked in alcohol to degrease and dehydrate them, resulting in degreased and dehydrated crab shells; Preservation: The degreased and dehydrated crab shells are immersed in a preservative solution for preservation treatment, and then the remaining preservative solution on the surface of the degreased and dehydrated crab shells is removed and dried to obtain preserved crab shells; Shaping: The preservative material and degreased cotton are mixed to obtain the filling material, which is then filled into the shell and appendages of the preservative crab shell to obtain the shaped crab shell; Air-dried: The shaped crab shells are air-dried to obtain air-dried crab shells; Sealing and color fixing: The air-dried crab shells are sealed and color-fixed to obtain sealed and color-fixed crab shells; Encapsulation: The sealed and color-fixed crab shell is encapsulated to obtain a specimen.

2. The method for preparing a shell specimen of a molted crab according to claim 1, characterized in that, The crab shell has a double-layered structure.

3. The method for preparing a shell specimen of a molted crab according to claim 1, characterized in that, The mass concentration of the calcium chloride solution is 0.5% to 1%.

4. The method for preparing a shell specimen of a molted crab according to claim 1, characterized in that, The immersion temperature for the activation treatment is 22℃~28℃, and the immersion time is 20min~30min.

5. The method for preparing a shell specimen of a molted crab according to claim 1, characterized in that, The degreasing and dehydration process includes a first stage, a second stage, a third stage, and a fourth stage; The alcohol concentration in the first stage is 50%, the degreasing and dehydration temperature is 20℃~22℃, and the soaking time is 4h~8h. The second stage involves an alcohol concentration of 75%, a degreasing and dehydration temperature of 22℃~25℃, and a soaking time of 4h~8h. The third stage involves an alcohol concentration of 95%, a degreasing and dehydration temperature of 25℃~28℃, and a soaking time of 4h~8h. The alcohol used in the fourth stage is anhydrous ethanol, and the degreasing and dehydration temperature is 25℃~28℃, with a soaking time of 0.8h~1.5h.

6. The method for preparing a shell specimen of a molted crab according to claim 1, characterized in that, The preservative solution includes formalin solution and sodium salicylate solution.

7. The method for preparing a shell specimen of a molted crab according to claim 6, characterized in that, The formalin solution in the preservative solution has a volume concentration of 4% to 6%, and the sodium salicylate solution has a volume concentration of 4% to 6%.

8. The method for preparing a shell specimen of a molted crab according to claim 7, characterized in that, The corrosion-resistant materials include phenol, alum, and camphor.

9. The method for preparing a shell specimen of a molted crab according to claim 1, characterized in that, After the degreased and dehydrated crab shells are soaked in a preservative solution for preservation treatment, the preservative solution is drawn out using a medical syringe and injected into the pores of the degreased and dehydrated crab shells using a multi-point injection method.

10. The method for preparing a shell specimen of a molted crab according to claim 1, characterized in that, In the encapsulation step, the sealed and color-fixed crab shell is placed inside a transparent specimen box, and the specimen box is filled with nitrogen gas.

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