A multi-component composite plant-based 3D printing nutritional ink for dysphagia population and a preparation method thereof

Abstract

The application discloses a kind of multi-component composite plant-based 3D printing nutrition ink suitable for dysphagia population and preparation method thereof, belong to food processing technical field.The application includes the following steps: preparation of snakehead skin collagen: fish skin is soaked and impurities is removed, and fish skin collagen is obtained by acid enzyme combined extraction, salting-out and freeze-drying;Preparation of vegetable puree: vegetables are peeled, washed, diced, boiled, wall broken and stirred, and sieved to form a paste for preparing edible ink;Preparation of 3D printable composite plant-based ink: pea protein isolate and vegetable puree are dissolved in water, xanthan gum and fish skin collagen are added, and uniformly stirred to obtain 3D printable composite plant-based ink.The application develops a food formula rich in nutrition and safe and easy to swallow for dysphagia patients through 3D printing technology, which can maintain a specific texture and consistency while being rich in essential nutrients, significantly improving the eating experience of patients.

Description

Technical Field

[0001] This invention belongs to the field of food processing technology, and mainly relates to a multi-component composite plant-based 3D printing nutritional ink suitable for people with swallowing difficulties and its preparation method. Background Technology

[0002] The elderly population is a high-risk group for dysphagia, and the development of foods suitable for patients with dysphagia has broad application potential in the food industry. For most patients with dysphagia, texture modification is one of the most effective dietary management strategies, often involving processing food into mashed, thickened, or pureed forms. While these foods are easier to swallow, they often lack visual appeal and fail to stimulate the patient's appetite, potentially leading to reduced food intake, weight loss, and malnutrition. Therefore, improving the texture, appearance, and nutritional balance of foods for patients with dysphagia has become a key challenge in addressing their dietary needs. Currently, 3D food printing is an innovative emerging technology that, due to its ability to personalize the nutrition, texture, and appearance of food, is considered the best management strategy for solving these problems.

[0003] Dietary recommendations for older adults emphasize the intake of protein-rich foods to ensure adequate calorie intake, maintain muscle mass and strength, and support overall health. Pea protein isolate, as a high-quality natural protein, possesses excellent nutritional and functional properties, and is hypoallergenic and highly bioavailable, making it an ideal protein source for the dietary needs of older adults.

[0004] Freshwater fish processing waste, such as fish skin and bones, is rich in collagen and is a potential source of natural collagen extraction. Snakehead fish (Channa argus) is an important commercially farmed fish, primarily in Asia. Its processing byproducts, such as skin and bones, account for approximately 50%-70% of the raw material and are generally of low value, with their rich bioactive components not being effectively developed and utilized. These byproducts are often used as feed or low-value fertilizer, and improper handling can cause environmental pollution due to foul odors. Therefore, utilizing fish skin to prepare high-value-added fish skin collagen can not only bring significant economic and environmental benefits, but its inherent nutritional value and gelatinous properties can also serve as a key ingredient, softening food texture and enriching it with protein, thus meeting the dietary needs of patients with dysphagia.

[0005] 3D food printing (3DFP) technology offers numerous advantages, including: providing personalized dietary plans for health benefits; enhancing the visual appeal of alternative protein sources; automating food preparation; and reducing food waste. To date, most 3DFP research has only used dehydrated and freeze-dried food powders for extrusion printing. However, freeze-dried foods suffer from the loss of nutrients such as vitamin C, vitamin E, and folic acid, and excessive ice crystal formation can damage the cell wall structure of fruits and vegetables. Therefore, using fresh vegetables to prepare food inks and employing 3D printing technology can create visually appealing and safe dietary products suitable for patients with swallowing difficulties. Vegetables are an important source of vitamins, minerals, water, and antioxidants in the diet, making them an ideal choice for dietary formulation. However, due to their high water content and extremely low carbohydrate and fat content, they are challenging to print as non-natural extrusion inks. Adding water-soluble colloids such as xanthan gum is necessary to adjust their rheological properties and texture to meet the requirements of 3D printing.

[0006] This invention utilizes 3D printing technology to develop a multi-component, nutrient-rich, high-calorie, safe, and easy-to-swallow food formula for patients with dysphagia. This formula not only ensures that the diet is rich in essential nutrients such as vitamins, dietary fiber, and protein, but also maintains the texture and consistency required by patients with dysphagia. The synergistic effect of each component significantly enhances the nutritional value and overall appeal of the diet, meeting the specific dietary needs of patients with dysphagia, improving their eating experience, and enhancing the enjoyment and health benefits of the meal. Summary of the Invention

[0007] This invention discloses a 3D printing nutritional formula for a multi-component composite plant-based ink for foods with difficulty swallowing, and provides a method for preparing the printing formula of this plant-based composite ink, which can effectively improve the texture properties, rheological properties and printability of the ink. The prepared ink can be used to make foods with difficulty swallowing.

[0008] The technical problem to be solved by this invention is achieved through the following technical solution: a method for preparing a 3D printable composite plant-based ink for foods that are difficult to swallow, comprising the following steps:

[0009] Pea protein isolate and vegetable puree are dissolved in an appropriate amount of water, and then thoroughly mixed with xanthan gum and snakehead fish skin collagen to make ink. The ink is then mechanically stirred to achieve uniformity and sealed with food-grade plastic wrap to obtain 3D printable composite plant-based ink.

[0010] The preparation method of the above-mentioned 3D printable composite plant-based ink for foods with swallowing difficulties, and the preparation method of snakehead fish skin collagen are as follows: the snakehead fish skin is washed; then soaked in an alkaline solution; then soaked in an alcohol solution to remove impurities such as fat and pigments from the fish skin; the alcohol solution on the surface of the fish skin is washed off with pure water and drained for later use; the pretreated fish skin is mixed with acetic acid, pepsin is added, and extracted; subsequently, snakehead fish skin collagen is obtained by salting out, dialysis, and freeze drying.

[0011] The above-mentioned method for preparing a 3D printable composite plant-based ink for foods with swallowing difficulties includes soaking in an alkaline solution using 8 times the volume of 0.1 mol / L NaOH solution, changing the solution every 8 hours, and rinsing the fish skin with pure water before changing to fresh solution, for a total of 3 times; and soaking in an alcohol solution using a 20% ethanol solution under stirring conditions for 24 hours, changing the ethanol solution every 6 hours.

[0012] The above-mentioned method for preparing a 3D printable composite plant-based ink for foods with difficulty swallowing, wherein the concentration of the acetic acid solution is 0.5 mol / L, the solid-liquid ratio of the pretreated fish skin to the acetic acid solution is 1g:70mL, and the amount of pepsin added is 1% of the mass of the fish skin.

[0013] The above-mentioned method for preparing 3D printable composite plant-based ink for foods with swallowing difficulties includes the following method for preparing vegetable puree: Select fresh vegetables, peel, wash and dice them by hand as needed, boil them in water until fully cooked, remove excess water, blend them with a high-speed blender until a smooth and uniform puree texture is obtained, and then sieve the puree. The resulting puree is used to prepare edible ink.

[0014] The above-mentioned method for preparing a 3D printable composite plant-based ink for foods with swallowing difficulties includes vegetables such as zucchini, carrots, and potatoes, with a mass ratio of 1:1:1.

[0015] The above-mentioned method for preparing a 3D printable composite plant-based ink for foods with difficulty swallowing involves a vegetable puree to water mass ratio of 1:1.

[0016] The above-mentioned method for preparing a 3D printable composite plant-based ink for foods with swallowing difficulties involves pea protein isolate at a mass of 5% to 15% of the total mass of vegetable puree and water, and xanthan gum at a mass of 0.5% to 1.5% of the total mass of the pea protein isolate-vegetable puree composite ink.

[0017] In the above-mentioned method for preparing a 3D printable composite plant-based ink for foods with swallowing difficulties, the mass of snakehead fish skin collagen in step three is 0.1% to 0.3% of the total mass of pea protein isolate-vegetable puree composite ink.

[0018] A 3D printable composite plant-based ink for use in foods that are difficult to swallow, prepared according to the above method.

[0019] Compared with existing technologies, the beneficial effects of this invention are as follows: The food formula developed by this invention is safe and easy to swallow, multi-component, and high in calories; the combination of pea protein isolate, vegetable puree, and fish skin collagen ensures that the diet is rich in essential nutrients such as vitamins, dietary fiber, and protein, and the synergistic effect between the components significantly enhances the nutritional value of the diet while increasing the overall appeal of the food; the final formula not only meets the specific dietary needs of people with swallowing difficulties but also improves their overall eating experience, making meals more enjoyable and healthier; the raw and auxiliary materials used in this invention are widely available, the processing technology is simple and easy to implement, and the cost is low, making the prepared products suitable for people with swallowing disorders and showing good application prospects. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the preparation process of the present invention.

[0021] Figure 2 The image shows (A) and (B) of the 3D printed sample of the ink prepared by the method of the present invention.

[0022] Figure 3 The rheological properties diagram of the ink prepared by the method of the present invention is shown, wherein A is the linear viscoelastic region diagram, B is the apparent viscosity diagram, C is the storage modulus and loss modulus diagram, and D is the loss factor diagram.

[0023] Figure 4 The Fourier transform infrared absorption spectrum of the ink prepared by the method of this invention is shown. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to some embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the protection scope of this invention.

[0025] Example 1: Preparation of collagen from snakehead fish skin

[0026] Wash the snakehead fish skin 2-3 times with pure water and drain. Then soak it in 8 times its volume of 0.1mol / L NaOH solution, changing the solution every 8 hours. Before changing to fresh solution, rinse the fish skin with pure water, repeating this process 3 times. Next, soak the fish skin in 20% ethanol solution for 24 hours (stirring constantly and changing the ethanol solution every 6 hours) to remove impurities such as fat and pigments. Finally, wash the surface of the fish skin with pure water to remove the ethanol solution and drain. Mix the pretreated fish skin with 0.5mol / L acetic acid at a ratio of 1g:70mL, add pepsin at 1% of the fish skin mass, and extract for 48 hours. Subsequently, obtain snakehead fish skin collagen through salting out, dialysis, and freeze-drying.

[0027] Example 2: Preparation of Vegetable Puree

[0028] Select fresh vegetables (zucchini, carrots, and potatoes in a 1:1:1 ratio), peel, wash, and dice them by hand as needed. Boil them in water for 15 minutes until fully cooked, remove excess water, and blend them in a high-speed blender for 5-10 minutes until a smooth and uniform puree is obtained. Then, sieve the vegetable puree to prevent solid particles from clogging the nozzle. The final puree is used to prepare edible ink.

[0029] Example 3: Preparation and property determination of composite plant-based 3D printing nutrient ink

[0030] (I) Preparation of composite plant-based 3D printing nutrient ink

[0031] First, take 15g of pea protein isolate and dissolve it in 50g of water. Add 50g of vegetable puree prepared in Example 2. Then, thoroughly mix the pea protein isolate-vegetable puree composite solution with 1.15g of xanthan gum and 0.35g of snakehead fish skin collagen prepared in Example 1 to make an ink formula. The ink formula is mechanically stirred to achieve homogeneity. The beaker containing the ink is sealed with food-grade plastic wrap to prevent moisture loss. The sealed ink can be used directly for 3D printing or stored in the refrigerator for later use.

[0032] Preferably, in this embodiment, the mass of pea protein isolate is 15% of the total mass of vegetable puree and water;

[0033] Preferably, in this embodiment, the mass of xanthan gum is 1% of the total mass of the pea protein isolate-vegetable puree composite ink;

[0034] Preferably, in this embodiment, the mass of the snakehead fish skin collagen is 0.3% of the total mass of the pea protein isolate-vegetable puree composite ink.

[0035] (II) Property determination

[0036] 1. 3D printing and dimensional deviations of composite plant-based 3D printing nutrient ink

[0037] Different ink formulations were printed using a 3D food printer (Shiyin Technology, China). Printing parameters were set as follows: nozzle diameter 0.84 mm, ambient temperature 20±2℃; a pagoda model was used, measuring 34.30 mm × 34.30 mm × 15.05 mm (length × width × height), which was used to evaluate the printability and repeatability of the 3D print. After printing, the samples were photographed to observe their shape and structural fidelity; simultaneously, the actual length, width, and height dimensions of the samples were measured using calipers, with each sample measured three times in parallel. The dimensional deviations of the printed model in the three directions (length, width, and height) were calculated using the following formula:

[0038]

[0039] In the formula, a positive value indicates that the printed sample is thicker than the design size, and a negative value indicates that the printed sample is thinner than the design size.

[0040] The printed result is as follows Figure 2 As shown, samples with 0.5% xanthan gum (XG) and 5% pea protein isolate (PPI) exhibited significant deformation, deviating completely from the expected shape, with the largest dimensional deviation observed in the height direction. In contrast, inks with 1% and 1.5% XG and 10% and 15% PPI concentrations produced printed samples with surface structures that closely matched the target geometry and exhibited smoothness. The dimensional deviation of the printed model decreased with increasing XG and PPI concentrations in the ink. However, when the XG and PPI concentrations were too high (XG 1.5%, PPI 15%), the printed model surface showed cracks and holes, and a rough surface structure, leading to decreased printing accuracy.

[0041] 2. Rheological property characterization of composite plant-based 3D printing nutrient ink

[0042] The rheological properties of the ink were evaluated using an HR10 rheometer manufactured by Thermomix (TAI). Parallel plates (PP) were used for testing, with a plate spacing of 1000 μm. A thin layer of silicone oil was coated onto the surface of the parallel plates before the experiment to reduce moisture evaporation from the sample. The tests included measurements at shear rates ranging from 0.1 to 100 s⁻¹. -1 The viscosity of the samples was evaluated within a certain range; dynamic oscillation frequency sweeps were performed at 1% strain, with an angular frequency range of 0.1–100 rad / s; oscillatory strain tests were conducted at 1 Hz, with a strain range of 0.01%–100%. All test temperatures were maintained at 25°C, consistent with actual printing conditions, and each sample was tested in triplicate to ensure the reliability and accuracy of the results.

[0043] like Figure 3 As shown in A, the linear viscoelastic region (LVR) of the sample was determined by strain sweep experiment. The elastic modulus (G′) and viscous modulus (G″) of all inks remained relatively stable within the strain range of 0.1%-10%, indicating that the ink network structure was in a dynamic equilibrium state, and the upper limit strain of LVR was about 10%. As shown in Figure 3 B, the apparent viscosity of the ink exhibits shear thinning behavior, which can affect the continuous flow of the ink during extrusion and the recovery performance after extrusion. The apparent viscosity of the ink increases with the increase of XG and PPI concentrations; in addition, after adding snakehead fish skin collagen (FC) to the system, the ink viscosity further increases. With the increase of shear rate, the apparent viscosity of all formulated inks decreased significantly, showing strong shear thinning properties. This property has significant advantages for targeted foods consumed by patients with dysphagia—during swallowing, when a constant tongue pressure pushes the bolus to the pharynx, it can promote easier swallowing of food. The above results further confirm that adding XG, PPI and FC can effectively enhance the rheological properties of the ink.

[0044] Viscoelasticity, evaluated by frequency sweep measurement of storage modulus (G′) and loss modulus (G"), is a key quality indicator for swallowing meals, which directly affects the pleasure and difficulty of swallowing. As Figure 3 C shows, all ink formulations exhibit a strong gel network structure. Throughout the scanning frequency range, G′ and G" remain relatively stable, and G′ is always greater than G" at the same frequency, indicating that the internal network structure of the ink has the unique toughness of a gel structure. As Figure 3 D shows, the loss factor (tanδ) of all inks is lower than 1 over the entire test frequency range. tanδ represents the ratio of G" to G′. The lower the value, the stronger the elasticity of the system, the more compact the network structure, and the higher the hardness of the sample. The above results show that all formulated inks are viscoelastic materials, mainly exhibiting solid-like behavior, showing G′ > G" (0.1<tanδ <1) in the test frequency range, having weak gel properties, and showing obvious frequency-dependent response, which meets the rheological requirements of dysphagia food, confirming that all formulations show dominant elastic behavior in viscoelastic properties. In addition, tanδ <1.0 is used as a rheological standard for safe swallowing of food for patients with dysphagia, indicating that the ink of the formulation of the present invention is suitable for safe consumption by the elderly.

[0045] 3. Characterization of texture properties of composite plant-based 3D printing nutritional inks

[0046] Dietary inks for dysphagia were prepared in 10 mL glass bottles. The outer wall of the glass bottle simulated the oral cavity environment. A texture analyzer probe was used to simulate oral chewing movements through compression-recovery, and a reverse compression test was conducted in total texture (TPA) mode. The test speed was set to 0.5 mm / s, and the compression deformation was set to 30%.

[0047] The total texture analysis (TPA) results of the composite plant-based 3D printing nutritional ink are shown in Table 1. The food ink formed by combining XG, PPI, FC, and vegetable puree significantly improved the texture of meals, thereby increasing patient satisfaction. Hardness, viscosity, and chewiness increased significantly with the addition of XG, PPI, and FC. Although this may have a slight impact on the swallowing process of patients with dysphagia, it effectively improved the 3D printing effect of the ink. The elasticity of the ink increased with increasing XG concentration within a certain range; furthermore, the cohesiveness of the ink also increased to some extent with increasing XG and PPI concentrations. These results indicate that higher concentrations of XG and PPI make the ink more elastic and cohesive, able to withstand compression during swallowing, thus making it safer for patients with dysphagia. With increasing concentrations of each component, the adhesiveness and chewiness of the ink also increased, and semi-solid foods with appropriate adhesiveness and chewiness are very suitable for the dietary needs of patients with dysphagia. At the same time, increasing FC concentration significantly strengthened the network structure of the ink, making it more resilient and elastic. Based on the TPA results, considering the extrudability and self-supporting properties of the ink, the G0.5 and P5 ink formulations, due to their lower hardness, viscosity, and viscousness, exhibit poor self-supporting properties and are therefore unsuitable for 3D printing of foods with swallowing difficulties. The ink formulations of this invention can be easily compressed between the tongue and palate without biting or chewing, making them suitable for elderly individuals with tooth loss, low chewing efficiency, and difficulty swallowing liquid foods.

[0048] Table 1 Texture Analysis of Food Ink

[0049] Puree <![CDATA[9.23±0.57 g ]]> <![CDATA[5.03±0.50 g ]]> <![CDATA[4.80±0.93 g ]]> <![CDATA[7.27±3.16 e ]]> <![CDATA[0.36±0.20 f ]]> <![CDATA[0.52±0.08 c ]]> G0.5-P15 <![CDATA[20.67±0.58 e ]]> <![CDATA[8.47±0.40 f ]]> <![CDATA[8.38±0.07 bcd ]]> <![CDATA[17.83±3.29 c ]]> <![CDATA[1.47±0.27 d ]]> <![CDATA[0.86±0.14 a ]]> G1-P5 <![CDATA[18.53±0.96 e ]]> <![CDATA[7.77±0.59 f ]]> <![CDATA[8.39±0.20 bcd ]]> <![CDATA[15.73±3.17 cd ]]> <![CDATA[1.30±0.29 de ]]> <![CDATA[0.84±0.13 a ]]> G1-P10 <![CDATA[24.07±1.46 d ]]> <![CDATA[9.63±1.10 e ]]> <![CDATA[7.57±0.38 de ]]> <![CDATA[18.43±0.95 c ]]> <![CDATA[1.37±0.11 d ]]> <![CDATA[0.77±0.03 ab ]]> G1-P15 <![CDATA[31.23±2.14 c ]]> <![CDATA[13.47±0.15 c ]]> <![CDATA[8.27±0.11 bcd ]]> <![CDATA[27.03±4.34 b ]]> <![CDATA[2.19±0.35 c ]]> <![CDATA[0.86±0.08 a ]]> G1.5-P15 <![CDATA[45.17±3.37 a ]]> <![CDATA[17.07±1.03 a ]]> <![CDATA[8.94±0.26 ab ]]> <![CDATA[42.13±6.41 a ]]> <![CDATA[3.69±0.46 a ]]> <![CDATA[0.93±0.07 a ]]> G1-P15-0.1C <![CDATA[32.67±3.18 c ]]> <![CDATA[13.67±0.72 c ]]> <![CDATA[8.32±0.15 bcd ]]> <![CDATA[30.63±5.93 b ]]> <![CDATA[2.50±0.45 bc ]]> <![CDATA[0.93±0.10 a ]]> G1-P15-0.2C <![CDATA[33.87±2.82 bc ]]> <![CDATA[13.83±0.58 c ]]> <![CDATA[9.32±0.08 a ]]> <![CDATA[29.73±5.56 b ]]> <![CDATA[2.54±0.51 bc ]]> <![CDATA[0.87±0.11 a ]]> G1-P15-0.3C <![CDATA[36.73±2.29 b ]]> <![CDATA[15.03±0.47 b ]]> <![CDATA[8.71±0.14 abc ]]> <![CDATA[32.23±5.75 b ]]> <![CDATA[2.95±0.53 b ]]> <![CDATA[0.87±0.09 a ]]>

[0050] Note: Puree represents a mixed vegetable puree without added protein and gum; G represents xanthan gum concentration (%); P represents pea protein isolate concentration (%); and C represents fish skin collagen concentration (%). For example, G1-P15-0.1C represents a compound ink with 1% xanthan gum, 15% pea protein isolate, and 0.1% fish skin collagen. Results are expressed as standard deviation ± mean. Different letters in the same column of the table indicate significant differences (p < 0.05).

[0051] 4. Fourier Transform Infrared (FT-IR) Analysis of Composite Plant-Based Ink

[0052] The spectral absorption properties of ink samples with different formulations were evaluated using a FT-IR spectrometer (TENSOR II, Bruker, Germany). The inks were lyophilized and then ground into powder using a mortar and pestle, and mixed thoroughly with KBr at a mass ratio of 1:100. Each sample was tested at room temperature (25°C) at 4000–400 cm⁻¹. ﹣1 Tests were conducted within the band, with the following parameters set: scan speed 0.2 cm / s, resolution 4 cm. ﹣1 .

[0053] FT-IR can provide information on functional groups and chemical bonds in food. The infrared spectra of plant-based ink composite systems with different concentrations of XG, PPI, and FC are shown below. Figure 4 As shown, the absorption bands of all ink samples are similar, with no disappearance of old characteristic peaks and no appearance of new characteristic peaks. However, the intensity and position of the characteristic peaks differ, indicating that physical interactions occurred between the components in the system, but no new functional groups were formed. All ink samples exhibited broad absorption peaks in the range of 3300 cm⁻¹ to 3400 cm⁻¹, which are the stretching vibration peaks of hydroxyl groups (OH), mainly originating from polysaccharide and protein components in the system, reflecting the formation of hydrogen bonds within the system. When XG, PPI, and FC were added, the characteristic peaks at this location gradually shifted towards 3300 cm⁻¹. -1 The shift of the nearby low wavenumber region indicates enhanced hydrogen bond interactions within the system. As the concentration of each component further increases, the characteristic peak of the hydroxyl (OH) group continues to shift to lower wavenumbers, indicating that with the increase of XG, PPI, and FC concentrations, the intermolecular interactions within the system are significantly enhanced, and the hydrogen bond network structure becomes more stable.

[0054] 5. Data Analysis

[0055] Texture analysis was performed in at least five parallel experiments, while other measurements were performed in three parallel experiments. All experimental data were analyzed using SPSS 27.0 statistical software and are expressed as mean ± standard deviation. The significance level was set at p ≤ 0.05. Origin 2025b software was used for data plotting and analysis.

Claims

1. A method for preparing a 3D printable composite plant-based ink for foods that are difficult to swallow, characterized in that, Includes the following steps: Pea protein isolate and vegetable puree are dissolved in an appropriate amount of water, and then thoroughly mixed with xanthan gum and snakehead fish skin collagen to make ink. The ink is then mechanically stirred to achieve uniformity and sealed with food-grade plastic wrap to obtain 3D printable composite plant-based ink.

2. The method for preparing a 3D printable composite plant-based ink for foods with difficulty swallowing according to claim 1, characterized in that, The preparation method of snakehead fish skin collagen is as follows: snakehead fish skin is washed; then soaked in an alkaline solution; subsequently, the fish skin is soaked in an alcohol solution to remove impurities such as fat and pigments; the alcohol solution on the surface of the fish skin is washed off with pure water and drained for later use; the pretreated fish skin is mixed with acetic acid, pepsin is added, and extraction is performed; subsequently, snakehead fish skin collagen is obtained through salting out, dialysis, and freeze drying.

3. The method for preparing a 3D printable composite plant-based ink for foods with swallowing difficulties according to claim 2, characterized in that, The alkaline solution soaking involves soaking the fish in 8 times its volume of 0.1 mol / L NaOH solution, changing the solution every 8 hours, and rinsing the fish skin with pure water before changing to fresh solution, for a total of 3 times; the alcohol solution soaking involves soaking the fish in a 20% ethanol solution for 24 hours under stirring, changing the ethanol solution every 6 hours.

4. The method for preparing a 3D printable composite plant-based ink for foods with difficulty swallowing according to claim 2, characterized in that, The concentration of the acetic acid solution is 0.5 mol / L, the solid-liquid ratio of the pretreated fish skin to the acetic acid solution is 1 g: 70 mL, and the amount of pepsin added is 1% of the mass of the fish skin.

5. A method for preparing a 3D printable composite plant-based ink for foods with difficulty swallowing, as described in claim 1, characterized in that, The method for preparing vegetable puree is as follows: Select fresh vegetables, peel, wash and dice them as needed, cook them in water until fully cooked, remove excess water, blend them in a high-speed blender until a smooth and uniform puree texture is obtained, sieve the puree, and use the resulting puree to prepare edible ink.

6. A method for preparing a 3D printable composite plant-based ink for foods with swallowing difficulties according to claim 5, characterized in that, The vegetables include zucchini, carrots, and potatoes, and the mass ratio of the three is 1:1:

1.

7. The method for preparing a 3D printable composite plant-based ink for foods with difficulty swallowing according to claim 1, characterized in that, The mass ratio of vegetable puree to water is 1:

1.

8. A method for preparing a 3D printable composite plant-based ink for foods with difficulty swallowing, as described in claim 1, characterized in that, The mass of pea protein isolate is 5% to 15% of the total mass of vegetable puree and water, and the mass of xanthan gum is 0.5% to 1.5% of the total mass of pea protein isolate, vegetable puree and water.

9. A method for preparing a 3D printable composite plant-based ink for foods with swallowing difficulties according to claim 1, characterized in that, The collagen content of snakehead fish skin is 0.1% to 0.3% of the total mass of pea protein isolate, vegetable puree, and water.

10. A 3D printable composite plant-based ink for use in foods that are difficult to swallow, prepared according to any one of claims 1 to 9.

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