Inkjet printing of inks based on inulin complexes

Abstract

The present application provides a kind of variable color 3D printing material based on inulin complex, the variable color 3D printing material includes inulin, calcium salt, magnesium salt and zinc salt.The variable color 3D printing material of the present application significantly improves the gelation performance of pure inulin, greatly shortens its gelation time, significantly improves the 3D printing formability, printing precision and water holding capacity of pure inulin gel, has rich variable color and color stability.

Description

Technical Field

[0001] This invention relates to a color-changing 3D printing material based on inulin complex and its printing method, belonging to the field of 3D printing technology. Background Technology

[0002] With the advancement of technology, food 3D printing technology, as an emerging food processing method, is gradually gaining widespread attention. This technology, through precise control of the layer-by-layer deposition of materials, enables personalized customization of food shape, texture, and nutritional components, bringing unprecedented innovation opportunities to the food industry. However, selecting suitable printing materials has always been one of the key factors restricting the development of food 3D printing technology.

[0003] Inulin is a soluble dietary fiber with multiple benefits, including improving gut health, promoting probiotic growth, enhancing immunity, and regulating blood sugar and lipid levels. Therefore, it is considered a natural functional food ingredient. In the field of food 3D printing, inulin is often used as an ingredient to improve the gel properties of proteins or other key printing materials. However, inulin's high water solubility and viscosity make it difficult to form stable and fine structures during 3D printing, resulting in low precision, poor formability, and susceptibility to dehydration and deformation in the printed product. These limitations make it difficult to use inulin directly as a primary raw material for additive manufacturing 3D printing, thus restricting its widespread application in the food 3D printing field. Summary of the Invention

[0004] This invention provides a color-changing 3D printing material based on inulin complex and its printing method, which can effectively solve the above-mentioned problems.

[0005] This invention is implemented as follows:

[0006] A color-changing 3D printing material based on an inulin complex, the color-changing 3D printing material comprising inulin, calcium salt, magnesium salt and zinc salt.

[0007] In some embodiments, the calcium salt is one or more of calcium chloride, calcium sulfate, and calcium carbonate.

[0008] In some embodiments, the magnesium salt is one or more of magnesium chloride, magnesium sulfate, and magnesium carbonate.

[0009] In some embodiments, the zinc salt is one or more of zinc chloride, zinc sulfate, and zinc carbonate.

[0010] In some embodiments, the color-changing 3D printing material further includes food coloring.

[0011] In some embodiments, the food coloring is one or more of beetroot red, anthocyanin, turmeric, lutein, and carotene.

[0012] In some embodiments, the color-changing 3D printing material comprises 5-8 parts inulin, 0.02-0.3 parts anthocyanin, 0.01-0.2 parts calcium chloride, 0.002-0.02 parts zinc chloride, and 0.05-1 parts magnesium chloride.

[0013] A method for printing the aforementioned color-changing 3D printing material, characterized by comprising the following steps:

[0014] S1. Mix all the raw materials, add water, heat and stir at a temperature of 50-90℃, a stirring speed of 200-600rpm, and a stirring time of 3-8min. Then, put the mixture into a printing tube and let it stand for 2-24 hours to allow it to completely form a gel.

[0015] S2, set the printing parameters to perform 3D printing.

[0016] In some embodiments, the printing parameters are: nozzle diameter 0.5-1mm, extrusion volume 100%-300%, layer height 0.4-0.6mm, nozzle temperature 10-45℃, and nozzle moving speed 15-40mm / s.

[0017] In some embodiments, the amount of water added is such that the inulin concentration is 0.5-0.8 g / mL.

[0018] The beneficial effects of this invention are:

[0019] The color-changing 3D printing material of the present invention, with the addition of calcium, magnesium and zinc minerals, significantly improves the gelation properties of pure inulin and greatly shortens its gelation time.

[0020] The color-changing 3D printing material of the present invention, with the addition of calcium, magnesium and zinc minerals, significantly improves the 3D printing formability, printing accuracy and water retention of pure inulin gel.

[0021] The color-changing 3D printing material of the present invention has rich color-changing properties and color stability. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0023] Figure 1The graphs show the gelation time of each formulation experimental group and control group in Example 1. A: Inverted graph of formulation 1 gel after 20 min of preparation and standing; B: Inverted graph of formulation 2 gel after 5 min of preparation and standing; C: Inverted graph of formulation 3 gel after 5 min of preparation and standing; D: Comparison of average gelation time between formulation 1 and the control; E: Comparison of average gelation time between formulation 2 and the control; F: Comparison of average gelation time between formulation 3 and the control.

[0024] Figure 2 The images show the printability of the experimental and control groups for each formulation in Example 2. A: 3D printed images of formulation one and the control; B: 3D printed images of formulation two and the control; C: 3D printed images of formulation three and the control.

[0025] Figure 3 The image shows the gelation time of the two variants in Example 3. A: Inverted images after the gels of the two variants have been prepared and left to stand for 0, 3, 4, 5, and 8 minutes; B: Comparison of the average gelation time of the two variants.

[0026] Figure 4 This is a diagram showing the accuracy and water retention of the printed product in Example 4. A: Comparison of 3D printed products; B: Comparison of XYZ axis fidelity of 3D printed products; C: Comparison of daily water loss rate of 3D printed products; D: Internal structure diagram of the 3D printed product obtained by MRI scanning.

[0027] Figure 5 The diagram shows the color variability and stability of the formulation in Example 5. A: Color comparison of the gel of the present invention under three pH conditions; B: Comparison of the five-pointed star printed by the gel of the present invention under three pH conditions; C: Comparison of the printed product after soaking in 3% hydrogen peroxide; D: Comparison of the change rate of anthocyanin solution absorption at 520nm after treatment with 3% hydrogen peroxide for 30 minutes. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Embodiments of this invention relate to a color-changing 3D printing material based on a special inulin complex. This complex not only contains inulin but also incorporates various minerals beneficial to health, specifically calcium, magnesium, and zinc salts. By combining these components, this invention aims to provide a 3D printing material that accelerates the gelation rate of inulin, thereby significantly improving its gelation properties. This improvement makes the material perform better during 3D printing, better adaptable to the requirements of printing equipment, and produces printed products with better stability and less susceptibility to water loss. This color-changing 3D printing material is not only technologically innovative but also demonstrates unique advantages in practical applications, bringing new possibilities to the field of 3D printing.

[0030] In some specific embodiments, the calcium salt mentioned can be one of calcium chloride, calcium sulfate, and calcium carbonate, or a combination of these calcium salts. For example, the calcium salt can be calcium chloride alone, a mixture of calcium sulfate and calcium carbonate, or any combination of these three calcium salts.

[0031] In some specific embodiments, the magnesium salt mentioned can be one of magnesium chloride, magnesium sulfate, and magnesium carbonate, or a combination of these magnesium salts. For example, the magnesium salt can be magnesium chloride alone, a mixture of magnesium sulfate and magnesium carbonate, or any combination of these three magnesium salts.

[0032] In some specific embodiments, the zinc salt mentioned can be one of zinc chloride, zinc sulfate, and zinc carbonate, or a combination of these zinc salts. For example, the zinc salt can be zinc chloride alone, a mixture of zinc sulfate and zinc carbonate, or any combination of these three zinc salts.

[0033] In some specific embodiments, this color-changing 3D printing material also includes one or more food colorings. These food colorings play an important role in color mixing during the printing process, enabling the final printed product to exhibit a rich and varied color effect. Specifically, in these embodiments, the food colorings used can be one or a combination of several of beetroot red, anthocyanins, turmeric, lutein, and carotene. These food colorings not only provide vibrant colors but also ensure that the printed product is visually appealing.

[0034] Meanwhile, the added minerals such as calcium, magnesium, and zinc enhance the stability and durability of these food colorings. These minerals provide a degree of protection, preventing them from gradually oxidizing under prolonged exposure to air. As a result, even during extended use, the printed products will not exhibit significant fading, ensuring rich color and better visual appeal. This combination not only improves the product's aesthetics but also extends its color retention time in various environments, making 3D printed products more reliable and durable in practical applications.

[0035] In some embodiments, the color-changing 3D printing material comprises 5-8 parts inulin, 0.02-0.3 parts anthocyanin, 0.01-0.2 parts calcium chloride, 0.002-0.02 parts zinc chloride, and 0.05-1 parts magnesium chloride.

[0036] In some specific embodiments, this color-changing 3D printing material contains multiple components to achieve its unique color-changing properties. Specifically, the material includes inulin as the main component, with a content ranging from 5 to 8 parts. The addition of inulin provides the necessary basic structure for the material, enabling it to maintain its shape and stability during the printing process.

[0037] In addition, the material contains anthocyanins, a natural pigment, at a concentration between 0.02 and 0.3 parts. The presence of anthocyanins allows 3D-printed objects to display different colors depending on environmental conditions, such as changes in temperature, humidity, or pH. This color-changing characteristic makes the material highly valuable for various applications.

[0038] To further enhance the material's performance, calcium chloride was added, at a concentration between 0.01 and 0.2 parts. The main function of calcium chloride is to adjust the material's hardness and flexibility, giving it better mechanical properties during printing. Simultaneously, calcium chloride also enhances the material's thermal stability, making it less prone to deformation at high temperatures.

[0039] To further optimize the material's performance, zinc chloride was added at a concentration between 0.002 and 0.02 parts. The addition of zinc chloride helps improve the material's corrosion resistance and antibacterial properties, allowing it to maintain good performance even in harsh environments. Furthermore, zinc chloride enhances the material's transparency, making it more attractive in certain specific applications.

[0040] Finally, to ensure the overall performance of the material, magnesium chloride was added, with a content between 0.05 and 1 part. The main function of magnesium chloride is to enhance the strength and toughness of the material, making it less prone to breakage or deformation under external forces. At the same time, magnesium chloride can also improve the processing performance of the material, making it smoother during the 3D printing process.

[0041] In summary, by precisely controlling the proportions of these components, a 3D printing material with excellent color-changing properties can be prepared, making it widely applicable in various scenarios.

[0042] A method for printing a color-changing 3D printing material includes the following steps: First, various raw materials are mixed, then an appropriate amount of water is added, followed by heating and stirring. During stirring, the temperature needs to be controlled between 50-90℃ to promote inulin absorption of water and expansion, allowing it to combine with other raw materials to form a stable gel. If the temperature is too low, the raw materials will not dissolve sufficiently, resulting in incomplete gel formation; if the temperature is too high, the inulin may degrade or denature, leading to an unstable gel structure. Simultaneously, the stirring speed is adjusted between 200-600 rpm to ensure uniform dispersion and steady gel formation of the raw materials. If the stirring speed is too low, the raw materials will not disperse well and may easily agglomerate, hindering gel formation; if the stirring speed is too high, it may cause excessive shearing, damaging the gel structure. The stirring time should also be controlled between 3-8 minutes to ensure thorough mixing of the raw materials. After stirring, the mixture is loaded into a printing tube and allowed to stand for 2-24 hours to allow it to fully gel.

[0043] Next, set the printing parameters and perform 3D printing. In some specific embodiments, the printing parameters can be set as follows: nozzle diameter of 0.5-1mm, extrusion volume of 100%-300%, layer height of 0.4-0.6mm, nozzle temperature of 10-45℃, and nozzle movement speed of 15-40mm / s.

[0044] In some specific embodiments, the amount of water added needs to be precisely controlled to ensure that the inulin concentration is between 0.5-0.8 g / mL, so as to ensure that the performance of the printing material and the printing effect are optimal.

[0045] Example 1

[0046] The gelation time of the formulation of this invention

[0047] Within the predetermined mixing ratio range, we selected three ratios as experimental cases, as detailed below:

[0048] Formula 1: Inulin: Anthocyanin: Calcium chloride: Zinc chloride: Magnesium chloride = 6:0.02:0.045:0.009:0.82.

[0049] Formula 2: Inulin: Anthocyanin: Calcium chloride: Zinc chloride: Magnesium chloride = 7:0.05:0.025:0.01:0.75.

[0050] Formula 3: Inulin: Anthocyanin: Calcium chloride: Zinc chloride: Magnesium chloride = 8:0.15:0.020:0.005:0.60.

[0051] Each formulation includes a corresponding control, containing only inulin and anthocyanins, and no minerals. Units are in grams, and the amount of water added is 10 mL.

[0052] Heat and stir each component at 60°C, 500 rpm, and for 6 minutes. Then, pour the mixture into a printing tube and let it stand to form a gel.

[0053] Record the time required for each experimental group and control group to reach a gel-like state (specifically, the contents do not drip when the container is inverted) after the magnetic stirrer is completed, in order to evaluate the gel-forming speed of the two groups. The experimental results are as follows: Figure 1 As shown.

[0054] Figure 1 The results revealed an interesting phenomenon: when observed at the same time point, we could clearly see that samples in all experimental groups formed gel structures earlier than their respective control groups (e.g., ...). Figure 1 A, Figure 1 B and Figure 1 (As shown in C). Further analysis of these experimental data revealed that the gelation time of each formulation group was significantly shorter than that of their respective control groups, and this difference was statistically significant (P<0.05). Figure 1 D、 Figure 1 E and Figure 1 As shown in F, these results demonstrate that the addition of minerals significantly accelerates the gelation rate of inulin. The sample in formulation two, in particular, exhibits a remarkably rapid gelation rate, forming a gel in approximately 3 minutes, compared to approximately 15 minutes for the control group. This increased gelation rate is significant for improving production efficiency, as it can significantly shorten the production cycle and thus reduce production costs. Furthermore, a faster gelation rate also signifies greater potential for industrial applications, as rapid gelation improves the continuity and stability of the production process, thereby providing strong support for large-scale production.

[0055] Example 2

[0056] 3D printability of the formulation of this invention

[0057] Prepare and gel according to the proportions of each experimental group and control group in Example 1.

[0058] To further evaluate the 3D printing effect of different proportions, we selected a columnar structure (height: 12mm, diameter: 15mm, infill density: 0%) as the printing model. We 3D printed the model using a nozzle diameter of 1mm, an extrusion rate of 200%, a layer height of 0.5mm, a printing temperature of 25℃, and a printing speed of 15mm / s, observing the forming process of the printed product. The experimental results are as follows: Figure 2 As shown.

[0059] Figure 2 The experimental results showed that the printed products obtained from the different formulations exhibited excellent shape retention and edge sharpness. These products demonstrated high stability during the molding process, effectively maintaining the intended shape and structural integrity. In contrast, the products in the control group showed significant defects, including partial collapse and structural incompleteness. These problems made it difficult for the control group products to maintain the intended shape, resulting in relatively poor formability. This comparison further confirms the positive role of minerals in enhancing the 3D printability of inulin gel. The addition of minerals significantly improved the gel's molding ability and the quality of the printed products, resulting in a significant improvement in shape retention and edge sharpness. This finding has important reference value and practical significance for future applications in 3D printing, particularly in food printing and bioprinting.

[0060] Example 3

[0061] The effect of various minerals in the formulation of this invention on inulin gelation

[0062] Based on the experimental results of Examples 1 and 2, we selected formulation two, which had the fastest gelation rate, to investigate in depth the effects of the three minerals on inulin gelation. We prepared variants of formulation two with zinc, calcium, or magnesium removed, and precisely measured their gelation times according to the method in Example 1. The experimental results are as follows: Figure 3 As shown.

[0063] Figure 3 Figure A details the gelation process of different formulations of inulin at 0, 3, 4, 5, and 8 minutes. The figures clearly show that each mineral promotes the gelation rate of inulin to varying degrees, with magnesium playing a particularly significant role. When magnesium is removed, gelation takes longer to occur, approximately 8 minutes to be observed. Furthermore, a synergistic effect exists among the three minerals, working together to further accelerate the gelation rate of inulin. This conclusion is supported by… Figure 3 Further validation of the average gelation time data in section B. The results showed that formulation 2 had the shortest average gelation time, followed by the de-calcified, de-zincified, and de-magnesiumized variants of formulation 2, while the inulin control group, which contained no minerals, had the longest gelation time. These differences were statistically significant (P-value less than 0.05), indicating that the results were statistically significant.

[0064] Example 4

[0065] The precision and water retention of the printed product formulated in this invention

[0066] A cube (length: 15mm, width: 15mm, height: 15mm, infill density: 40%) was used as the printing model. The nozzle diameter was set to 0.84mm, the extrusion rate to 150%, the layer height to 0.5mm, the printing temperature to 25℃, and the printing speed to 15mm / s. 3D printing was performed on the experimental and control groups according to the formulation ratio of Example 1. The actual dimensions of the printed products in the length (X-axis), width (Y-axis), and height (Z-axis) of both groups were measured. These measurements were compared with the target dimensions set for the original model, and the fidelity of each dimension was calculated, i.e., fidelity = |(measured value - target size)| / target size × 100%. Fidelity reflects the degree of deviation between the actual printed size and the target size. Higher fidelity means that the printed product is more consistent with the original model in shape, i.e., the better the printing accuracy.

[0067] Depend on Figure 4 As can be seen from Figure A, the cubes printed in the experimental group exhibited higher shape retention and edge sharpness, demonstrating better formability; while the control group's cubes partially collapsed, resulting in incomplete structures, difficulty in maintaining shape, and poorer formability. XYZ axis fidelity comparison data ( Figure 4 B) indicates that the fidelity of the experimental composition along the XYZ axes was significantly higher than that of the control group, approaching 100%, with a statistically significant difference (P<0.05). This demonstrates that the finished product printed using the formula of this invention can more accurately reproduce the dimensions of the original model, reduce dimensional deviations, and achieve higher printing accuracy.

[0068] Subsequently, we used magnetic resonance imaging (MRI) to scan the printed product and evaluate the integrity and homogeneity of its internal structure. Integrity primarily considers whether the pores formed as expected, without unexpected breakage or defects; while homogeneity focuses on whether the pores are evenly distributed within the sample, avoiding over-concentration or uneven distribution. MRI scan results ( Figure 4 D) shows that the finished product printed using the formulation of this invention has a uniform and regular internal structure with excellent integrity, which can further visually verify its high printability and printing accuracy. In contrast, during MRI scanning, the control group collapsed due to the excessively soft gel texture, resulting in its internal structure being basically stuck together and no regular porous structure was observed.

[0069] After examining the printing accuracy, we further evaluated the water-holding capacity of the printed products in the second formulation experimental group and the control group. To this end, we weighed the cubes immediately after printing and recorded the initial weight. Then, we placed each product under the same environmental conditions (room temperature 25℃, humidity 65%) for 24 hours, and weighed them again after 24 hours. By comparing the difference between the initial and 24-hour weights, we calculated the daily water loss rate of the product, i.e., (initial weight - weight after 24 hours) / initial weight × 100%. The daily water loss rate indirectly reflects the material's ability to retain moisture over a period of time; the lower the value, the better the water-holding capacity of the material, and the more effectively it can retain internal moisture.

[0070] Figure 4 The results showed that, compared with the control group, the finished product printed with the formula of this invention (experimental group) had a lower water loss rate after 24 hours, and the difference was statistically significant (P<0.05). This indicates that its water-holding capacity has been improved, which will help maintain the taste of the product.

[0071] Example 5

[0072] Color-changing properties of the formulation of this invention

[0073] By carefully adjusting the pH value of the two gel formulations, we can meticulously observe and record the different color changes exhibited by the gel under varying acidity and alkalinity. This process helps us to conduct an in-depth evaluation and analysis of the color-changing properties of the formulation of this invention. Next, we used a pentagram model for printing to further verify whether the finished product printed using this specific model could also exhibit similar color-changing properties. Figure 5 A and Figure 5 As demonstrated by B, the gel and its printed product exhibit a charming peach-pink color at pH 4; the color shifts to a more delicate pink at pH 6; and a striking pea-green at pH 11. This color-changing property, influenced by pH variations, not only adds interest and appeal to the product but also provides greater scope and limitless possibilities for personalized design and diverse applications.

[0074] Color stability of the formulation of this invention

[0075] An oxidative environment was simulated using 3% hydrogen peroxide. A two-variant solution containing only anthocyanins and minerals was used as the experimental group, and a solution containing only anthocyanins was used as the control group. The absorbance of both solutions was measured using a microplate reader at 520 nm (the characteristic absorption peak of anthocyanins) immediately after the addition of hydrogen peroxide and 30 minutes later. The rate of change in absorbance before and after the two time points was calculated as (initial 520 nm absorbance - 520 nm absorbance after 30 minutes) / initial 520 nm absorbance × 100%. This rate of change was used to evaluate the stability of anthocyanins in the formulation of this invention under oxidative conditions.

[0076] according to Figure 5 Data from D showed that the absorbance change rate of the experimental group was significantly lower than that of the control group, with a difference of approximately 2 times, which was statistically significant (P<0.05). This result indicates that under the strong oxidizing effect of hydrogen peroxide, the anthocyanins in the experimental group exhibited higher stability and were less prone to degradation. This, to some extent, proves that the addition of minerals can indeed protect anthocyanins.

[0077] To further verify this finding, we immersed the printed products from both the experimental and control groups (both containing inulin) in a 3% hydrogen peroxide solution after they had been stored for 4 days. After immersion for 5 minutes, we carefully observed and recorded the color changes of the two groups. Figure 5 As shown in Figure C, under the strong oxidizing effect of hydrogen peroxide, the printed products in the control group showed obvious fading (anthocyanins were oxidized and decomposed). However, in the experimental group, due to the effective protection of anthocyanins by minerals, the color fading of the printed products was significantly slowed down, demonstrating higher color stability. This result further supports the view that minerals have a protective effect on anthocyanins.

[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A color-changing 3D printing material based on inulin complex, characterized in that, The color-changing 3D printing material includes 5-8 parts inulin, 0.02-0.3 parts anthocyanin, 0.01-0.2 parts calcium chloride, 0.002-0.02 parts zinc chloride, and 0.05-1 parts magnesium chloride.

2. A printing method for the color-changing 3D printing material according to claim 1, characterized in that, Includes the following steps: S1. Mix all the raw materials, add water, heat and stir at a temperature of 50-90℃, a stirring speed of 200-600rpm, and a stirring time of 3-8min. Then, put the mixture into a printing tube and let it stand for 2-24 hours to allow it to completely form a gel. S2, set the printing parameters to perform 3D printing.

3. The printing method according to claim 2, characterized in that, The printing parameters are: nozzle diameter 0.5-1mm, extrusion volume 100%-300%, layer height 0.4-0.6mm, nozzle temperature 10-45℃, and nozzle moving speed 15-40mm / s.

4. The printing method according to claim 2, characterized in that, The amount of water added is such that the inulin concentration is 0.5-0.8 g / mL.

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