Blueberry composite gel system and 3D printing method thereof

Abstract

The invention discloses a blueberry composite gel system and a 3D printing method thereof.The blueberry composite gel system is prepared through the following method that 1, by weight, 12 parts of starch, 40 parts of blueberry puree and 0-4 parts of food colloid are weighed and dissolved in 44-48 parts of water to be dispersed and mixed to be uniform, and a mixed solution is obtained; and (2) fully gelatinizing the mixed solution at 90 DEG C under a stirring condition to obtain the blueberry composite gel system. The blueberry composite gel system prepared by the preparation method disclosed by the invention has relatively high flowability and self-supporting property, and can be used as a 3D printing material; the texture of the 3D printing product is changed through freeze-drying treatment, and the storage stability is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D food printing, and in particular to a blueberry composite gel system and a 3D printing method thereof. Background Art

[0002] 3D food printing is a new food manufacturing method. The characteristic of this technology is the layer-by-layer deposition of materials to accurately construct a preset physical structure. 3D food printing emphasizes the printability of materials, including fluidity, support and formability. Currently, 3D food printing research mostly uses starch and food colloids as printing materials. Starch has shear-thinning properties when dissolved in water and is often used as a base material for 3D food printing, but its mechanical strength usually cannot meet the requirements of 3D printing. Food colloids exert a cross-linking effect by forming non-covalent bonds such as hydrophobic interactions or hydrogen bonds between molecules, and are often used to improve the 3D printing properties of materials. Blueberry puree is rich in anthocyanins, vitamins, pectin, etc., and has antioxidant and immune-enhancing functions. It is expected to be widely used as a formula additive in foods with high nutritional value and health-promoting effects.

[0003] Current research on 3D food printing mainly focuses on optimizing food colloid components and process parameters. For example, patent CN119817773 A uses lotus root powder and whey protein as basic raw materials, optimizes the material ratio, gelatinization time, gelatinization temperature and rotation speed, and realizes 3D printing of lotus root powder and whey protein. Patent CN 118452445 A discloses a starch food processing method that can achieve complex 3D printed food shapes. Pregelatinized high-amylose starch, corn starch, and protein are compounded into a composite gel to obtain 3D printed products with complex shapes. However, 3D food printing still faces problems such as low printing efficiency, low mechanical strength, and poor storage stability, which limits its application in the food processing industry to ready-to-eat products. Research on post-processing to improve the texture characteristics of 3D printed products and increase storage stability is relatively scarce. Summary of the Invention

[0004] The object of the present invention is to provide a blueberry composite gel system and a 3D printing method thereof.

[0005] The technical solution adopted by the present invention to solve its technical problem is: A blueberry composite gel system is prepared by the following method: (1) According to weight, weigh 12 parts of starch, 40 parts of blueberry puree, and 0-4 parts of food colloid, dissolve them in 44-48 parts of water, and disperse and mix them to obtain a mixed solution; (2) The mixed solution was fully gelatinized at 90°C under stirring conditions to obtain a blueberry composite gel system.

[0006] Preferably, in step (1), the food colloid is 1-4 parts.

[0007] Preferably, in step (1), the starch is one or more of corn starch, potato starch, sweet potato starch, and wheat starch.

[0008] Preferably, in step (1), the food colloid is k - One or more of carrageenan, xanthan gum, guar gum, gelatin, and konjac gum.

[0009] Preferably, in step (2), the stirring speed is 450-600 rpm, and the optimal stirring speed is 500 rpm.

[0010] Preferably, in step (2), the gelatinization time is 10-15 min.

[0011] A 3D printing method for a blueberry composite gel system comprises the following steps: using Tinkercad modeling software to establish a 3D model of a printing target; pouring the blueberry composite gel system according to claim 1 into a barrel of a printer; setting printing parameters of the 3D printer; and performing printing to obtain a blueberry composite gel 3D printed product.

[0012] Preferably, the printing parameters of 3D printing are: printer nozzle size is 0.84 mm, printing speed is 15 mm / s, printing layer height is 0.8 mm, number of printing layers is 30, and filling density is 60%.

[0013] Preferably, the blueberry composite gel system is poured into the barrel of the printer, and the barrel temperature is set to 60° C. and kept constant for 20 minutes.

[0014] Preferably, a post-processing method is also included, which is: placing the obtained blueberry composite gel 3D printed product into a freezer at -80°C for 8-10 hours, and then transferring it to a vacuum freeze dryer for freeze drying for 1 day.

[0015] The beneficial effects of the present invention are as follows: the present invention compounds blueberry puree, food colloid, and corn starch into a blueberry composite gel system, which has high fluidity and self-supporting properties and is suitable for processing 3D printed products. At the same time, the freeze-drying process changes the texture of the 3D printed gel, thereby extending the storage stability, having distinctive characteristics and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the 3D printing process and model; Figure 2 The rheological properties of the gel system of Examples 1-5; Figure 3 is the moisture state of the gel system of Examples 1-5; Figure 4is the infrared spectrum of the gel system of Example 1-5; Figure 5 These are photos of 3D printed products of the gel systems of Examples 1-5; Figure 6 is the printing deviation value of the 3D printed product of the gel system of Examples 1-5; Figure 7 This is a freeze-dried photo of the 3D printed product of Example 2-4; Figure 8 is the freeze-dried shape fidelity of the 3D printed products of Examples 2-4; Figure 9 This is a photo of the rehydrated freeze-dried product of Example 2-4; Figure 10 This is the rehydration curve of the freeze-dried product of Example 2-4. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further described in detail below through specific embodiments.

[0018] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the following examples, unless otherwise specified, are all conventional methods in the art.

[0019] The sources of the raw materials used in the examples are: Blueberry puree: Yichun Shanye Beverage Co., Ltd. Corn starch: food grade, Foshan Haitian Flavoring & Food Co., Ltd. k -Carrageenan: food grade, Zhejiang Yinuo Biotechnology Co., Ltd.

[0020] Example 1 (1) Weigh 12 g of starch and 40 g of blueberry puree, dissolve them in 48 g of water, and mix them at 500 rpm for 300 s to obtain a mixed solution; (2) Gelatinization was performed at 90°C and 500 rpm for 10 min to fully gelatinize the corn starch and obtain a blueberry composite gel system; (3) The blueberry composite gel system prepared in step (2) was poured into the barrel of the printer, and the barrel temperature was set to 60°C and kept constant for 20 minutes; (4) Create a 3D model to be printed, with a nozzle size of 0.84 mm, a printing speed of 15 mm / s, a layer height of 0.8 mm, 30 layers, and a filling density of 60%. The process flow is as follows: Figure 1 shown.

[0021] Example 2 (1) Weigh 12 g starch and 40 g blueberry puree. k -1 g of carrageenan was dissolved in 47 g of water and dispersed and mixed at 500 rpm for 300 s to obtain a mixed solution; (2) Gelatinization was performed at 90°C and 500 rpm for 10 min to fully gelatinize the corn starch and obtain a blueberry composite gel system; (3) The blueberry composite gel system prepared in step (2) was poured into the barrel of the printer, and the barrel temperature was set to 60°C and kept constant for 20 minutes; (4) Create a 3D model to be printed. The printer nozzle size is 0.84 mm, the printing speed is 15 mm / s, the printing layer height is 0.8 mm, the number of printing layers is 30, and the filling density is 60%.

[0022] (5) The 3D printed product obtained in step (4) was placed in a -80°C freezer for 8 h before freeze-drying, and then transferred to a vacuum freeze dryer for freeze-drying for 1 day. The freeze-dried product was placed in 15 mL of water and allowed to stand at a constant temperature of 25°C for 2 min for rehydration.

[0023] Example 3 (1) Weigh 12 g starch and 40 g blueberry puree. k -2 g of carrageenan was dissolved in 46 g of water and dispersed and mixed at 500 rpm for 300 s to obtain a mixed solution; (2) Gelatinization was performed at 90°C and 500 rpm for 10 min to fully gelatinize the corn starch and obtain a blueberry composite gel system; (3) The blueberry composite gel system prepared in step (2) was poured into the barrel of the printer, and the barrel temperature was set to 60°C and kept constant for 20 minutes; (4) Create a 3D model to be printed. The printer nozzle size is 0.84 mm, the printing speed is 15 mm / s, the printing layer height is 0.8 mm, the number of printing layers is 30, and the filling density is 60%.

[0024] (5) The 3D printed product obtained in step (4) was placed in a -80°C freezer for 10 h before freeze-drying, and then transferred to a vacuum freeze dryer for freeze-drying for 1 day. The freeze-dried product was placed in 15 mL of water and allowed to stand at a constant temperature of 25°C for 2 min for rehydration.

[0025] Example 4 (1) Weigh 12 g starch and 40 g blueberry puree. k - 3 g of carrageenan was dissolved in 45 g of water and dispersed and mixed at 500 rpm for 300 s to obtain a mixed solution; (2) Gelatinization was performed at 90°C and 500 rpm for 10 min to fully gelatinize the corn starch and obtain a blueberry composite gel system; (3) The blueberry composite gel system prepared in step (2) was poured into the barrel of the printer, and the barrel temperature was set to 60°C and kept constant for 20 minutes; (4) Create a 3D model to be printed. The printer nozzle size is 0.84 mm, the printing speed is 15 mm / s, the printing layer height is 0.8 mm, the number of printing layers is 30, and the filling density is 60%.

[0026] (5) The 3D printed product obtained in step (4) was placed in a -80°C freezer for 8 h before freeze-drying, and then transferred to a vacuum freeze dryer for freeze-drying for 1 day. The freeze-dried product was placed in 15 mL of water and allowed to stand at a constant temperature of 25°C for 2 min for rehydration.

[0027] Example 5 (1) Weigh 12 g starch and 40 g blueberry puree. k -4 g of carrageenan was dissolved in 44 g of water and dispersed and mixed at 500 rpm for 300 s to obtain a mixed solution; (2) Gelatinization was performed at 90°C and 500 rpm for 10 min to fully gelatinize the corn starch and obtain a blueberry composite gel system; (3) The blueberry composite gel system prepared in step (2) was poured into the barrel of the printer, and the barrel temperature was set to 60°C and kept constant for 20 minutes; (4) Create a 3D model to be printed. The printer nozzle size is 0.84 mm, the printing speed is 15 mm / s, the printing layer height is 0.8 mm, the number of printing layers is 30, and the filling density is 60%.

[0028] The testing method of the blueberry composite gel system obtained in the embodiment of the present invention is as follows: (1) Rheological test The rheological properties were tested by rheometer, using a 20 mm stainless steel plate, a measuring gap of 1 mm, and a measuring temperature of 25°C. −1 The steady-state shear test was performed under the fixed strain of 0.1%, and the dynamic viscoelasticity test was performed under the angular frequency of 1 to 100 rad / s to obtain different k -Storage modulus (G′), loss modulus (G″), complex modulus (G*) and loss tangent (tan δ) of the gel system with carrageenan addition.

[0029] Figure 2 The rheological properties of the gel system of Examples 1-5 are as follows. k- With the increase of carrageenan addition, G′, G″ and G* of the gel system all showed an upward trend, which may be due to k -Carrageenan is a hydroxyl-rich polysaccharide that can connect with the hydrophilic layer of amylopectin through hydrogen bonds to form amylopectin-carrageenan complex. k -The interaction between carrageenan and corn starch leads to a decrease in the water absorption of starch. k - As the amount of carrageenan added increases, the fluidity of the gel system becomes worse, making printing more difficult. k - The gel system with the highest carrageenan addition had a tan δ < 1, and the loss modulus was greater than the storage modulus, indicating that each gel system tended to be an elastic material with solid-like properties, which was beneficial for maintaining the shape of the original model design and the shape stability of the printed object.

[0030] As the shear rate increases, the apparent viscosity of each gel system decreases, indicating that all gel systems exhibit shear thinning properties, which is a necessary condition for the successful extrusion of 3D printing materials. k -The addition amount of carrageenan is positively correlated, that is, as the addition amount of carrageenan increases, the viscosity of the gel system gradually increases. This may be because k -Carrageenan has a strong affinity for water and competes with starch molecules for binding water, thereby reducing the moisture content in the material and turning it into a gradually hardening material.

[0031] On the whole, the storage modulus, loss modulus, composite modulus and apparent viscosity of the gel system of Example 1 are the lowest, indicating that the gel system has high fluidity but poor support. When Example 2 shows a similar curve to the former, the rheological properties do not change much. The storage modulus, loss modulus, composite modulus and apparent viscosity of the gel systems of Examples 3-4 are significantly increased and the curves are relatively similar, and all have good fluidity and support. The storage modulus, loss modulus, composite modulus and apparent viscosity of the gel system of Example 5 are the largest, indicating that the support of the gel system is enhanced, but at the same time the fluidity is also weakened.

[0032] (2) Low-field nuclear magnetic resonance The water content and distribution of the gel were determined using low-field nuclear magnetic resonance (NMR). The magnetic field strength was 0.5 T and the temperature was 25°C. Before testing, an oil sample was used for calibration. A 4 g sample was placed in a 25 mm diameter glass tube. The parameters were: 119,992 sampling points, 100 kHz spectrum width, 4000 echoes, 8 repetitions, and a sampling repetition time of 1000 ms.

[0033] Table 1 Low-field NMR analysis of the gel system of Examples 1-5 .

[0034] Figure 3 As shown, the LF-NMR of the gel system has three peaks, among which T 21 Represents bound water in the material, which is tightly bound water in the system; T 22 Represents the semi-bound water in the material, which is the part of water bound in the starch matrix grid structure and shows a certain fluidity; T 23 represents free water, which is easily removed from the gel system, and the corresponding peak area percentages are P 21 、 P 22 and P 23 As shown in Table 1, with k - Increase in carrageenan addition, T 21 and T 22 The peak gradually shifts to the left. P 21 Gradually increasing, this may be due to k -Carrageenan is a polysaccharide with multiple hydroxyl groups and strong anionic properties. When its negative charges repel each other, its molecular chains form irregularly curled chain structures, which easily interact with starch molecules to form hydrogen bonds and interact with polar water molecules, thus firmly locking in moisture and increasing the water retention of the gel system. k - Increase in carrageenan addition, P 22 As the fluidity of the gel system decreases, it indicates that the hardness and viscosity of the gel system are gradually increasing, and the difficulty of extruding the material is gradually increasing. Within a certain range, the reduction in fluidity can bring more cross-linking and a dense network structure to the gel system, improving the mechanical strength of the gel system and making the appearance of the printed product more consistent with the designed model shape, which can improve the accuracy of 3D printing.

[0035] (3) Fourier transform infrared spectroscopy The sample was frozen at -80°C for 8 h and then freeze-dried in a vacuum freeze dryer for 1 day. The freeze-dried sample was mixed with KBr, ground, and pressed into thin sheets. The infrared spectrum range was 4000–400 cm −1 , resolution 4 cm −1 , scanned 32 times.

[0036] Depend on Figure 4 It can be seen that all samples have the peaks at 1128, 1645, 2921, and 3436 cm -1 There is an absorption peak near 1645 cm -1The characteristic peak near 2921 cm is attributed to the stretching vibration between water molecules and C=O in the non-crystalline region of the gel system. -1 The characteristic peak near 3436 cm is due to the antisymmetric stretching vibration of CH. -1 The absorption peak near 1128 cm is attributed to the stretching vibration of the OH bond. -1 、2921 cm -1 The characteristic peak nearby gradually redshifts to a wave number of 3436 cm -1 The characteristic peak of the gel system undergoes a red shift, which indicates that stronger hydrogen bonds are generated in the gel system, which has stronger self-support and deformation resistance, and is more conducive to the molding quality and stability of 3D printed products.

[0037] (4) Print deviation value Take a photo of the printed product and measure its actual length, width, and height. The printing accuracy of the printed product is evaluated using the length deviation value (L), width deviation value (W), and height deviation value (H). The calculation formulas are L =( l − l 0) / l 0×100% W =( w − w 0) / w 0×100% H =( h − h 0) / h 0×100% In the formula L 、 W 、 H Represent the length, width and height deviation values ​​respectively, %; l 、 w 、 h Represent the measured length, width, and height, mm; l 0. w 0. h 0 represents theoretical length, width, and height, mm respectively.

[0038] During the 3D printing process, the gel system not only needs to be smoothly extruded from a smaller nozzle, but also should have sufficient mechanical strength to maintain the stability of the printed structure, thereby forming the desired 3D printed product with higher printing accuracy. Figure 5-6 The 3D printing moldability of the gel system of the "moon cake" pattern, which is a traditional Chinese food, is shown. It is found that there are some differences in the surface properties and overall moldability of the gel systems with different formulas. k -Carrageenan gel system (Example 1) The printed product is severely deformed. This is because the low viscosity of the gel system ensures smooth extrusion, but the low storage modulus and composite modulus ( Figure 2 ) resulting in insufficient mechanical strength to maintain the stability of the printed structure, resulting in collapse. The self-supporting capacity of the gel systems of Examples 2-3 was enhanced, and the deviation of the printed product from the preset model was reduced. The gel system of Example 3 had the smallest deviations in length, width, and height, and the "FOOD LAB" logo was printed most clearly, effectively recreating the model and achieving the highest printing accuracy. The fluidity of the gel systems of Examples 4-5 weakened, and the deviation of the printed product from the preset model gradually increased. The gel system of Example 5 had too low fluidity, preventing smooth extrusion, resulting in broken lines and the inability to form the printed product.

[0039] (4) Full texture analysis A P / 6 cylindrical aluminum probe was used. The test temperature was 25°C, and the speed was 1.0 mm / s before, during, and after the test. The compressive strain was 40%. The hardness, elasticity, resilience, and adhesion of the sample were measured.

[0040] Table 2 Texture characteristics of Examples 1-5 .

[0041] As shown in Table 2, k - When the amount of carrageenan added increased from 0 to 4% (Examples 1-5), the hardness, cohesiveness, adhesiveness, and resilience all increased significantly ( P <0.05), while the adhesion had no significant change ( P >0.05), which may be due to k - With the addition of carrageenan, the hydroxyl groups on it form more hydrogen bonds with starch molecules, which increases the strength of the interaction in the gel system, resulting in an increase in the hardness and cohesiveness of the gel system. Therefore, the hardness of the gel system of Examples 1-3 increases, and its printability also increases ( Figure 6 ), while the higher hardness and cohesiveness of the gel system of Examples 4-5 make it difficult to extrude during the 3D printing process, and the printability is reduced. The gel system of Example 5 cannot be printed.

[0042] (5) Determination of moisture content of freeze-dried products Refer to the direct drying method in the "National Food Safety Standard - Determination of Moisture in Food" (GB 5009.3-2016) and use a moisture meter to determine the moisture content of freeze-dried products.

[0043] Table 3 Physical properties of freeze-dried products of Examples 2-4 .

[0044] Physical properties of the freeze-dried products of Examples 2-4 are shown in Table 3. k - With the increase of carrageenan addition, the moisture content and hardness of the product showed a significant upward trend (P < 0.05). This may be due to the k - Enhanced interaction between carrageenan molecules: the diameter of the internal network pores of the product increases with k - The smaller pores formed by the increase in carrageenan addition improve the water molecule retention capacity through the capillary effect; at the same time, the reduction in the internal porosity of the product leads to a greater structural compactness and higher hardness.

[0045] like Figure 7 The following is a photo of the freeze-dried product. Example 2 has many wrinkles and cracks on the surface, which may be due to the large pores inside the product ( Figure 7 ), the ability to resist the stress concentration caused by the volatilization of water during the freeze-drying process is poor, thus causing macroscopic wrinkles and cracks. Example 3 The freeze-dried product has no obvious wrinkles and cracks on the surface, and the words "FOOD LAB" are the clearest and the appearance is best maintained. This is because k - Increased carrageenan addition, k - The cross-linking between carrageenan and amylose molecules increases, and the internal pores of the product become denser, which can better resist the stress caused by ice crystal growth and volatilization, making it have the highest shape fidelity ( Figure 8 The surface of the freeze-dried product of Example 4 also has many wrinkles. This may be due to the large internal cross-linking degree. The water volatilization is limited during the freeze-drying process and remains inside the product, resulting in a difference in pore size between the inside and outside of the freeze-dried product, causing volume shrinkage.

[0046] (5) Determination of rehydration rate Add 15 mL of water to a beaker and place it in a constant temperature water bath at 25°C. Place the freeze-dried product in the beaker for rehydration. The initial freeze-dried product mass is (5.00 ± 0.12) g. Remove the rehydrated product from the water at regular intervals, wipe off the surface moisture, and weigh it using an electronic digital balance. The rehydration rate (R) is calculated as follows: R =( m − m 0) / m 0 In the formula R represents the rehydration rate, g / g; m represents the wet weight of the freeze-dried product, g; m 0 represents the dry weight of the freeze-dried product, g.

[0047] The photos of the rehydrated products of Examples 2-4 are as follows Figure 9As shown in the figure, there are cracks on the surface of Example 2. This may be due to the large internal pore size. The capillary effect will accelerate the entry of water into the pores, causing the product to absorb water and expand rapidly, thereby causing the generation of cracks. The appearance retention of Example 3 is better, with no obvious cracks. This is because its internal pore size is relatively dense, which can effectively resist the stress concentration generated during water absorption and expansion. There are a large number of cracks on the surface of Example 4 and the local rehydration is uneven. This may be due to its dense network structure. The limited volatilization of water during the early freeze-drying process leads to a large difference in the internal and external pore sizes of the product, which leads to different internal and external water absorption rates during rehydration, and local rapid water absorption and expansion, leading to the generation of cracks.

[0048] like Figure 10 The rehydration curves of the rehydrated products of Examples 2-4 at 25°C are shown. It can be observed that all gel systems absorb water quickly in the initial stage of rehydration, and as the rehydration rate approaches saturation, the rehydration rate gradually decreases. k - As the amount of carrageenan added increases, the rehydration process of the gel system slows down, which may be due to k -The addition of carrageenan increases the density of the cross-linked network inside the gel system, effectively prolongs the absorption and diffusion path of water, and reduces the migration rate of water molecules.

[0049] Table 4 Weibull and Peleg model fitting parameters for the rehydrated products of Examples 2-4 .

[0050] In order to further accurately predict and optimize the rehydration kinetics, two application models, Peleg and Weibull, were established in this study. The corresponding fitting parameters are shown in Table 4. The Weibull model is only for k - The gel rehydration curve with 3% carrageenan addition has a good fit ( R 2 >0.90), while the Peleg model can well describe the rehydration behavior of the gel ( R 2 >0.90), among which Example 3 has the highest fitting degree ( R 2 = 0.9592). The rate constant of the Peleg model α The smaller the product is, the faster the water absorption rate is. β The smaller the value, the greater the final moisture content of the rehydrated product. k - Increase in carrageenan addition, α 、 βBoth show an increasing trend, indicating that the product's rehydration rate and final moisture content are on a downward trend. This is because a higher carrageenan content increases the number of intermolecular bonds in the product, making the three-dimensional network denser and increasing the water absorption and diffusion paths, thereby reducing the water absorption rate and ultimately reducing the moisture content. Overall, Example 3 maintains a better appearance than other products and also has a higher fit to the Peleg model.

[0051] The embodiment described above is only a preferred solution of the present invention and does not limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solution described in the claims.

Claims

1. A blueberry composite gel system, characterized in that: Prepared by the following method: (1) According to weight, weigh 12 parts of starch, 40 parts of blueberry puree, and 0-4 parts of food colloid, dissolve them in 44-48 parts of water, and disperse and mix them to obtain a mixed solution; (2) The mixed solution was fully gelatinized at 90°C under stirring conditions to obtain a blueberry composite gel system.

2. A blueberry composite gel system according to claim 1, characterized in that: In step (1), the food colloid is 1-4 parts.

3. The blueberry composite gel system according to claim 1, characterized in that: In step (1), the starch is one or more of corn starch, potato starch, sweet potato starch, and wheat starch.

4. The blueberry composite gel system according to claim 1, characterized in that: In step (1), the food colloid is κ - One or more of carrageenan, xanthan gum, guar gum, gelatin, and konjac gum.

5. The blueberry composite gel system according to claim 1, characterized in that: In step (2), the stirring speed is 450-600 rpm.

6. The blueberry composite gel system according to claim 1, characterized in that: In step (2), the gelatinization time is 10-15 min.

7. A 3D printing method for a blueberry composite gel system, characterized in that: A 3D stereoscopic model of a printing target is established using Tinkercad modeling software, the blueberry composite gel system according to claim 1 is poured into the barrel of a printer, the printing parameters of the 3D printer are set, and printing is performed to obtain a blueberry composite gel 3D printed product.

8. The 3D printing method according to claim 7, characterized in that: The printing parameters of 3D printing are: printer nozzle size of 0.84 mm, printing speed of 15 mm / s, printing layer height of 0.8 mm, number of printing layers of 30, and filling density of 60%.

9. The 3D printing method according to claim 7, characterized in that: The blueberry composite gel system was poured into the barrel of the printer, and the barrel temperature was set to 60°C and kept constant for 20 minutes.

10. The 3D printing method according to claim 7, wherein: The invention also includes a post-processing method, which is as follows: placing the obtained blueberry composite gel 3D printed product into a freezer at -80°C for 8-10 hours, and then transferring it into a vacuum freeze dryer for freeze drying for 1 day.

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