A high internal phase emulsion ink material, and a method of making and use thereof

Abstract

The application relates to a high internal phase emulsion ink material and a preparation method and application thereof, and belongs to the technical field of emulsion ink material preparation. The preparation method of the high internal phase emulsion ink material provided by the application is as follows: a pulse electric field is used to treat a soybean protein isolate solution, then the soybean protein isolate solution is mixed with a polysaccharide solution as an aqueous phase, then vegetable oil and a bioactive substance are mixed as an oil phase, and finally the aqueous phase and the oil phase are mixed and high-speed sheared to prepare the high internal phase emulsion ink material. The high internal phase emulsion ink material prepared by the application has high stability after freeze-thaw storage and high retention rate of the bioactive substance, can effectively embed the bioactive substance, better realizes slow release of the bioactive component, achieves the purpose of targeted transport, improves the retention capacity of the emulsion to the internal phase substance under the freeze-thaw condition, has great application prospect and development potential in the preparation of 3D printing functional food, and can provide a new technical direction and technical support for the 3D printing functional food.

Description

Technical Field

[0001] This invention relates to a high internal phase emulsion ink material, its preparation method, and its application, belonging to the field of emulsion ink material preparation technology. Background Technology

[0002] 3D printing is increasingly being used in the pharmaceutical, healthcare, and food industries. It allows for highly customized food products, enabling enhanced nutritional content to meet individual dietary needs related to allergies or dietary restrictions through precise control of bioactive substances. High internal phase emulsions (HIPEs), as a two-phase system, are used to prepare ink materials for 3D printing. However, freeze-thaw instability has been a major problem in the application of HIPEs. The freeze-thaw instability of HIPEs can cause the layer around individual droplets to break down and allow the droplets to coalesce rapidly, leading to the separation of the HIPEs into the original aqueous and oil phases. This significantly compromises the encapsulation and utilization of the bioactive substances retained in the emulsion.

[0003] Soy protein isolate contains 20 essential amino acids, possessing high nutritional value and multifunctionality, and has been widely used in the food, cosmetics, and pharmaceutical industries. Soy protein isolate readily forms nano-sized protein particles, giving it a unique advantage in delivering fat-soluble nutrients. Furthermore, its amphiphilic (hydrophilic and hydrophobic) properties allow it to diffuse and adsorb at the oil droplet interface during emulsification, thus stabilizing the emulsion interface. Although numerous studies have recognized the emulsifying properties of soy protein isolate, its application in 3D printing still does not meet the high emulsifying performance requirements of food industry production, severely limiting its scope. Therefore, when using soy protein isolate alone as an emulsifier, its functional properties are generally enhanced through modification or the addition of polysaccharides.

[0004] However, current research on stable protein emulsion systems mainly involves first forming a protein-polysaccharide mixture before emulsion preparation. However, the resulting emulsions often suffer from low freeze-thaw stability and low retention of bioactive substances during application. Therefore, there is an urgent need to develop a novel method for preparing emulsion ink materials with high freeze-thaw stability and high retention of bioactive substances to comprehensively address these issues. Summary of the Invention

[0005] In view of the defects and shortcomings of the existing technology, the purpose of this invention is to provide a method for preparing high internal phase emulsion ink materials. The process is simple, suitable for industrial production, and the prepared ink material is a protein-based high internal phase emulsion with high stability after freeze-thaw storage and high retention rate of bioactive substances.

[0006] The present invention also aims to provide a high internal phase emulsion ink material prepared by the above preparation method, which has high stability after freeze-thaw storage and high retention rate of bioactive substances.

[0007] Another objective of this invention is to provide applications of the aforementioned high internal phase emulsion ink materials.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A method for preparing a high internal phase emulsion ink material includes the following steps:

[0010] (1) The soybean protein isolate solution is subjected to pulsed electric field treatment, and then polysaccharide solution is added and stirred to obtain protein-polysaccharide composite solution, with the protein-polysaccharide composite solution as the aqueous phase; separately, bioactive substances are mixed evenly with vegetable oil as the oil phase; wherein, the polysaccharide used in the polysaccharide solution is one of high methoxyl pectin, xanthan gum, and konjac mannan;

[0011] (2) The aqueous phase and oil phase are mixed and then sheared at high speed to obtain a high internal phase emulsion ink material.

[0012] In one embodiment, in step (1), the process conditions for the pulsed electric field treatment are: pulse intensity of 20-40 kV / cm, pulse width of 40-60 μs, pulse frequency of 0.8 k-1.2 kHz, and flow rate of 8-12 mL / min.

[0013] In one embodiment, in step (1), the stirring speed is 300-500 r / min, and the stirring time is 1-3 h.

[0014] Based on the consideration of further improving the stability of emulsion ink materials after freeze-thaw storage and the retention rate of bioactive substances, in one embodiment, in step (1), the mass concentration of the soy protein isolate solution is 30-50 mg / mL; the mass concentration of the polysaccharide solution is 15-25 mg / mL; and the mixing volume ratio of the soy protein isolate solution to the polysaccharide solution is (0.8-1.2):(0.8-1.2).

[0015] In a further preferred embodiment, the mass concentration of the soy protein isolate solution is 40 mg / mL; the mass concentration of the polysaccharide solution is 20 mg / mL; the mixing volume ratio of the soy protein isolate solution to the polysaccharide solution is 1:1; and the polysaccharide used in the polysaccharide solution is high-methoxyl pectin.

[0016] After encapsulating bioactive substances in the emulsion ink material, it does not significantly affect the particle size, microstructure, or 3D printing effect of the emulsion system. Therefore, this invention does not impose special restrictions on the types of bioactive substances. Technicians can conventionally select the types of bioactive substances encapsulated in the emulsion ink material according to the functionality and nutritional requirements of 3D printed food. In one embodiment, in step (1), the bioactive substance is one of curcumin, carotenoids, and astaxanthin; the mass concentration of the bioactive substance in the oil phase is 0.05% to 0.2%, more preferably 0.1%.

[0017] The type of vegetable oil does not significantly affect the performance of the emulsion ink material of this invention. Therefore, this invention does not impose any particular restrictions on the type of vegetable oil, and those skilled in the art can conventionally select suitable types of vegetable oil. In one embodiment, in step (1), the vegetable oil is one of soybean oil, corn oil, and peanut oil.

[0018] In one embodiment, in step (2), the volume ratio of the aqueous phase to the oil phase is 1:(3-5). More preferably, the volume ratio of the aqueous phase to the oil phase is 1:4.

[0019] In one embodiment, in step (2), the rotational speed of the high-speed shearing is 10,000 to 12,000 r / min, and the high-speed shearing time is 3 to 6 min.

[0020] A high internal phase emulsion ink material prepared by the above preparation method.

[0021] An application of the above-mentioned high internal phase emulsion ink material, as an ink material in 3D printed food.

[0022] The technical solution of the present invention has the following advantages and beneficial effects:

[0023] The method for preparing high internal phase emulsion ink material provided by the present invention involves first treating a soybean protein isolate solution with a pulsed electric field, then mixing it with a polysaccharide solution as an aqueous phase, and then mixing vegetable oil with bioactive substances as an oil phase. Finally, the aqueous and oil phases are mixed and subjected to high-speed shearing to obtain the high internal phase emulsion ink material.

[0024] The preparation method described above in this invention is simple, easy to control, and suitable for industrial production. In the preparation of the high internal phase emulsion, this invention employs a pulsed electric field (PEF) to treat the soy protein isolate solution. PEF is a short-duration electrotreatment technique. Through PEF treatment, this invention alters the secondary and tertiary structures of the protein, exposes more free amino groups, and enhances protein function. Simultaneously, the free radicals generated by the pulsed electric field treatment affect the intramolecular interactions of the protein and alter the ionic interactions of the protein, increasing its apparent charge and promoting the interaction between the protein and polysaccharides to form complexes. Furthermore, the polysaccharides selected in this invention can charge the oil droplets in the system, increasing the viscosity and stability of the emulsion. This can improve emulsion stability by reducing surface tension and increasing viscosity, promoting the spontaneous formation of smaller particle sizes under mechanical stirring. Finally, this invention utilizes the combination of soy protein isolate and polysaccharides to form an aqueous phase, which is then further combined with oil, thereby obtaining a freeze-thaw resistant high internal phase emulsion with excellent viscoelastic properties and stronger stability.

[0025] Experiments have confirmed that the high internal phase emulsion ink material prepared by this invention exhibits high stability after freeze-thaw storage and a high retention rate of bioactive substances. It effectively encapsulates bioactive substances, better achieving the slow-release and targeted transport of bioactive components, and improving the emulsion's retention capacity of internal phase substances under freeze-thaw conditions. Therefore, the high internal phase emulsion ink material prepared by this invention has enormous application prospects and development potential in the preparation of 3D printed functional foods, and can also provide new technical directions and support for 3D printed functional foods. Attached Figure Description

[0026] Figure 1 The average particle size diagrams are shown for the emulsion ink materials prepared in Examples 1-3 and Comparative Examples 1-4 of this invention.

[0027] Figure 2 These are laser confocal images of the emulsion ink materials prepared in Examples 1-3 and Comparative Examples 1-4 of the present invention.

[0028] Figure 3 These are 3D printing visual images of the emulsion ink materials prepared in Examples 1-3 and Comparative Examples 1-4 of the present invention.

[0029] Figure 4 The results show the encapsulation rate of curcumin in the emulsion ink materials prepared in Examples 1-3 and Comparative Examples 1-4 of this invention. Detailed Implementation

[0030] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to specific embodiments. It should be noted that, unless otherwise specified, the features in the embodiments of the present invention can be combined with each other. Many specific details are set forth in the following description to provide a thorough understanding of the present invention; however, the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below. For those skilled in the art, other embodiments can be obtained based on the provided embodiments without any creative effort.

[0031] In the following examples and comparative examples of this invention, the soy protein isolate used is from Shandong Yuwang brand. High-methoxyl pectin (62% esterification) is from Davisco Foods, USA. Xanthan gum (USP grade) is from Aladdin, Shanghai. Konjac mannan is from Shanghai Maclean Biochemical Technology Co., Ltd. Curcumin is from Aladdin, Shanghai. Unless otherwise specified, other raw materials are commercially available materials commonly used in the art.

[0032] In the following embodiments of the present invention, curcumin is used as an example to illustrate the encapsulation effect of the emulsion ink material and the retention rate of bioactive substances. In other embodiments, those skilled in the art can conventionally select the types of bioactive substances encapsulated in the emulsion ink material according to the functionality and nutritional requirements of 3D printed food. For example, the encapsulated bioactive substances can also be carotenoids or astaxanthin.

[0033] Example 1

[0034] This embodiment provides a high internal phase emulsion ink material, the preparation method of which includes the following steps:

[0035] (1) Dissolve 4g of soy protein isolate in 100mL of deionized water, stir at room temperature for 2 hours, then hydrate at 4℃ for 12 hours. After removing from the refrigerator, allow the solution to return to room temperature to obtain a 40mg / mL soy protein isolate solution. Separately, dissolve 2g of high-methoxyl pectin in 100mL of deionized water, stir at room temperature for 2 hours, then hydrate at 4℃ for 12 hours to obtain a 20mg / mL polysaccharide solution (high-methoxyl pectin solution).

[0036] (2) A 20 mL solution of soybean protein isolate with a concentration of 40 mg / mL was subjected to a pulsed electric field treatment. Then, a 20 mL solution of polysaccharide (high methoxylated pectin solution) with a concentration of 20 mg / mL was added. The mixture was stirred at 350 r / min for 2 h to obtain a protein-polysaccharide composite solution, which was used as the aqueous phase. The pulsed electric field treatment conditions were: pulse intensity of 30 kV / cm, pulse width of 50 μs, pulse frequency of 1.0 kHz, and flow rate of 10 mL / min. Curcumin was separately added to soybean oil and mixed evenly to obtain the oil phase. The mass concentration of curcumin in the oil phase was 0.1%.

[0037] (3) The aqueous phase and oil phase are mixed at a volume ratio of 1:4, and then sheared at high speed for 3 minutes at a speed of 12000 r / min to obtain the high internal phase emulsion ink material of this embodiment.

[0038] Example 2

[0039] This embodiment provides a high internal phase emulsion ink material, the preparation method of which includes the following steps:

[0040] (1) Dissolve 4g of soy protein isolate in 100mL of deionized water, stir at room temperature for 2 hours, then hydrate in a 4℃ refrigerator for 12 hours. After removing from the refrigerator, allow it to return to room temperature to obtain a 40mg / mL soy protein isolate solution. Dissolve 2g of xanthan gum in 100mL of deionized water, stir at room temperature for 2 hours, then hydrate in a 4℃ refrigerator for 12 hours to obtain a 20mg / mL polysaccharide solution (xanthan gum solution).

[0041] (2) A 20 mL solution of soybean protein isolate with a concentration of 40 mg / mL was subjected to a pulsed electric field treatment. Then, a 20 mL solution of polysaccharide (xanthan gum solution) with a concentration of 20 mg / mL was added, and the mixture was stirred at 350 r / min for 2 h to obtain a protein-polysaccharide composite solution. This protein-polysaccharide composite solution was used as the aqueous phase. The pulsed electric field treatment conditions were: pulse intensity of 30 kV / cm, pulse width of 50 μs, pulse frequency of 1.0 kHz, and flow rate of 10 mL / min. Curcumin was separately added to soybean oil and mixed thoroughly to obtain the oil phase. The mass concentration of curcumin in the oil phase was 0.1%.

[0042] (3) The aqueous phase and oil phase are mixed at a volume ratio of 1:4, and then sheared at high speed for 3 minutes at a speed of 12000 r / min to obtain the high internal phase emulsion ink material of this embodiment.

[0043] Example 3

[0044] This embodiment provides a high internal phase emulsion ink material, the preparation method of which includes the following steps:

[0045] (1) Dissolve 4g of soy protein isolate in 100mL of deionized water, stir at room temperature for 2 hours, then hydrate at 4℃ for 12 hours. After removing from the refrigerator, allow the solution to return to room temperature to obtain a 40mg / mL soy protein isolate solution. Dissolve 2g of konjac mannan in 100mL of deionized water, stir at room temperature for 2 hours, then hydrate at 4℃ for 12 hours to obtain a 20mg / mL polysaccharide solution (konjac mannan solution).

[0046] (2) A 20 mL solution of soybean protein isolate with a concentration of 40 mg / mL was subjected to a pulsed electric field treatment. Then, a 20 mL solution of polysaccharide (konjac mannan solution) with a concentration of 20 mg / mL was added, and the mixture was stirred at 350 r / min for 2 h to obtain a protein-polysaccharide composite solution. This protein-polysaccharide composite solution was used as the aqueous phase. The pulsed electric field treatment conditions were: pulse intensity of 30 kV / cm, pulse width of 50 μs, pulse frequency of 1.0 kHz, and flow rate of 10 mL / min. Curcumin was separately added to soybean oil and mixed evenly to obtain the oil phase. The mass concentration of curcumin in the oil phase was 0.1%.

[0047] (3) The aqueous phase and oil phase are mixed at a volume ratio of 1:4, and then sheared at high speed for 3 minutes at a speed of 12000 r / min to obtain the high internal phase emulsion ink material of this embodiment.

[0048] Comparative Example 1

[0049] This comparative example provides an emulsion ink material, the preparation method of which includes the following steps:

[0050] (1) Dissolve 4g of soy protein isolate in 100mL of deionized water, stir at room temperature for 2h, then place in a 4℃ refrigerator for 12h to hydrate, remove and return to room temperature to obtain a 40mg / mL soy protein isolate solution.

[0051] (2) Use the soy protein isolate solution obtained in step (1) as the aqueous phase. Separately, add curcumin to soybean oil and mix well to obtain the oil phase; the mass concentration of curcumin in the oil phase is 0.1%.

[0052] (3) Mix the aqueous phase and the oil phase at a volume ratio of 1:4, and then shear at high speed for 3 minutes at a speed of 12000 r / min to obtain the emulsion ink material of the comparative example.

[0053] Comparative Example 2

[0054] This comparative example provides an emulsion ink material, the preparation method of which includes the following steps:

[0055] (1) Dissolve 4g of soy protein isolate in 100mL of deionized water, stir at room temperature for 2 hours, then hydrate at 4℃ for 12 hours. After removing from the refrigerator, allow the solution to return to room temperature to obtain a 40mg / mL soy protein isolate solution. Dissolve 2g of high-methoxyl pectin in 100mL of deionized water, stir at room temperature for 2 hours, then hydrate at 4℃ for 12 hours to obtain a polysaccharide solution (high-methoxyl pectin solution).

[0056] (2) To 20 mL of a 40 mg / mL soy protein isolate solution, add 20 mL of a 20 mg / mL polysaccharide solution (high methoxylated pectin solution). Stir and mix at 350 r / min for 2 h to obtain a protein-polysaccharide composite solution, which is used as the aqueous phase. Separately, add curcumin to soybean oil and mix thoroughly to obtain the oil phase; the mass concentration of curcumin in the oil phase is 0.1%.

[0057] (3) Mix the aqueous phase and the oil phase at a volume ratio of 1:4, and then shear at high speed for 3 minutes at a speed of 12000 r / min to obtain the emulsion ink material of the comparative example.

[0058] Comparative Example 3

[0059] This comparative example provides an emulsion ink material, the preparation method of which includes the following steps:

[0060] (1) Dissolve 4g of soy protein isolate in 100mL of deionized water, stir at room temperature for 2h, then place in a 4℃ refrigerator for 12h to hydrate, remove and return to room temperature to obtain a 40mg / mL soy protein isolate solution.

[0061] (2) 40 mL of a 40 mg / mL soy protein isolate solution was subjected to a pulsed electric field treatment to obtain a pulse-treated soy protein isolate solution, which was used as the aqueous phase. The pulsed electric field treatment conditions were: pulse intensity of 30 kV / cm, pulse width of 50 μs, pulse frequency of 1.0 kHz, and flow rate of 10 mL / min. Curcumin was separately added to soybean oil and mixed thoroughly to obtain the oil phase; the mass concentration of curcumin in the oil phase was 0.1%.

[0062] (3) Mix the aqueous phase and the oil phase at a volume ratio of 1:4, and then shear at high speed for 3 minutes at a speed of 12000 r / min to obtain the emulsion ink material of the comparative example.

[0063] Comparative Example 4

[0064] This comparative example provides an emulsion ink material, the preparation method of which includes the following steps:

[0065] (1) Dissolve 4g of soy protein isolate in 100mL of deionized water, stir at room temperature for 2 hours, then hydrate at 4℃ for 12 hours. After removing from the refrigerator, allow the solution to return to room temperature to obtain a 40mg / mL soy protein isolate solution. Dissolve 2g of high-methoxyl pectin in 100mL of deionized water, stir at room temperature for 2 hours, then hydrate at 4℃ for 12 hours to obtain a 20mg / mL polysaccharide solution (high-methoxyl pectin solution).

[0066] (2) To 20 mL of a 40 mg / mL soy protein isolate solution, add 20 mL of a 20 mg / mL polysaccharide solution (high-methoxyl pectin solution). Stir and mix at 350 r / min for 2 h to obtain a protein-polysaccharide composite solution. Treat the protein-polysaccharide composite solution with a pulsed electric field. The pulsed electric field treatment conditions are: pulse intensity 30 kV / cm, pulse width 50 μs, pulse frequency 1.0 kHz, and flow rate 10 mL / min. Use the protein-polysaccharide composite solution after pulsed electric field treatment as the aqueous phase. Separately, add curcumin to soybean oil and mix thoroughly to obtain the oil phase; the mass concentration of curcumin in the oil phase is 0.1%.

[0067] (3) Mix the aqueous phase and the oil phase at a volume ratio of 1:4, and then shear at high speed for 3 minutes at a speed of 12000 r / min to obtain the emulsion ink material of the comparative example.

[0068] Experimental Example 1: Determination of Average Particle Size of Emulsion

[0069] The particle size (D) of the emulsion ink materials prepared in Examples 1-3 and Comparative Examples 1-4 was analyzed using a Mastersizer 3000 laser particle size analyzer. 3,2 The measurement was performed. The results are as follows: Figure 1 As shown.

[0070] Depend on Figure 1 It can be seen that there is a significant difference in particle size between the emulsion ink materials of the comparative examples and the embodiments, indicating that the addition of polysaccharide solution and the change in pulsed electric field treatment both affect the particle size of the emulsion. Compared with comparative examples 1-3, the emulsions of examples 1-3 have smaller particle sizes, indicating that the emulsions prepared by adding polysaccharide solution and applying a pulsed electric field have better stability. Compared with comparative example 4, the emulsions of examples 1-3 have smaller particle sizes, indicating that the emulsions prepared by first treating the protein solution with a pulsed electric field and then preparing the protein-polysaccharide composite solution have stronger stability.

[0071] Experimental Example 2: Microstructure Analysis of Emulsions

[0072] The microstructure of the emulsion ink materials prepared by the methods in Comparative Examples 1-4 and Examples 1-3 was analyzed using laser scanning confocal microscopy (CLSM). The specific steps were as follows: 20 μL of 0.2% (w / w) Nile Red solution and 20 μL of 0.5% (w / w) Nile Blue solution were added to the samples to stain the lipids and proteins. The staining process lasted 5 minutes. After staining, excess staining solution was aspirated, the samples were covered with coverslips, and observed under an objective lens at 20x magnification. Staining and observation were performed away from light. Nile Red and Nile Blue were observed at excitation and emission wavelengths of 488 / 543 nm and 561 / 613 nm, respectively. The laser confocal microscopy images of each emulsion ink material sample are shown below. Figure 2 As shown in the image. Green represents oil droplets, and blue represents protein.

[0073] Depend on Figure 2 As can be seen, compared with Comparative Examples 1-3, the droplets in the emulsion samples of Examples 1-3 and Comparative Example 4 of this invention are densely packed and uniformly distributed, with the droplet size of Example 1 being smaller and more uniform. The reduction in average particle size can shorten the distance between oil droplets, increase the interaction between oil droplets, and thus increase the stability of the emulsion.

[0074] Experiment Example 3: 3D Printing Test

[0075] 3D printing tests were conducted using the emulsion ink materials prepared in Comparative Examples 1-4 and Examples 1-3. Each test sample was filled into a plastic syringe of the same size and printed as a cube at room temperature through a nozzle with an inner diameter of 0.84 mm. The extrusion speed was 5 mm / s, the fill rate was 90%, and the shape was cubic. All printed samples were photographed. The 3D printed visual appearance of each emulsion ink material sample is shown below. Figure 3 As shown.

[0076] like Figure 3 As shown, all emulsion ink materials could pass smoothly through the printing nozzle; however, the accuracy and stability of the resulting cubes varied. Comparative Example 1 exhibited multi-layer fusion, structural collapse, and insufficient self-support. Comparative Example 2, by adding polysaccharides to the protein solution, improved the 3D printing properties of the protein emulsion to varying degrees, but the sample still showed insufficient self-support and partial collapse. Comparative Example 3 showed a significant improvement in texture contour, indicating that pulsed electric field treatment of the protein enhanced its adsorption at the oil-water interface, thus better stabilizing the emulsion. Comparative Example 4 and Examples 1-3 exhibited good printing performance, especially the cube printed in Example 1, which had the most accurate geometry and identifiable printing texture. Therefore, treating the protein with a pulsed electric field before forming a composite solution with polysaccharides achieves cross-linking between emulsion droplets, forming a denser three-dimensional network structure, which enhances the 3D printing properties of protein emulsions.

[0077] Experimental Example 4: Curcumin Encapsulation Efficiency Test

[0078] This experiment tested the encapsulation efficiency of curcumin. The test method was as follows: 0.2 g of the emulsion ink material samples prepared in Examples 1-3 and Comparative Examples 1-4 were mixed with 2 mL of n-hexane, and then centrifuged at 8000 rpm for 4 min to obtain free curcumin. The absorbance of the obtained supernatant was measured at 450 nm using a microplate reader, and the concentration of curcumin was measured using a standard curve. Encapsulation efficiency (%) = (1 - free curcumin / original curcumin concentration) × 100%. The encapsulation efficiency test results are as follows. Figure 4 As shown.

[0079] Depend on Figure 4 It can be seen that, compared with comparative examples 1 to 4, the present invention first treats soybean protein isolate with a pulsed electric field, and then forms a composite solution with polysaccharides as the aqueous phase. The prepared emulsion ink material has a better curcumin encapsulation rate (all reaching more than 85%), among which the curcumin encapsulation rate of Example 1 is the best (reaching 91.8%).

[0080] Experimental Example 5: Freeze-thaw stability of emulsions and curcumin retention rate test

[0081] Test method for freeze-thaw stability of emulsions: The emulsion ink materials prepared in Examples 1-3 and Comparative Examples 1-4 were respectively placed in 30mL glass vials and frozen at -22℃ for 24h, then thawed at 25℃ for 4h. This cycle was repeated 3 times to conduct the freeze-thaw test. The mass of the emulsion before each freeze-thaw was recorded as m0 (g), and the mass of the emulsion and centrifuge tube after freeze-thaw was recorded as m1 (g). The emulsion was centrifuged at 10000g for 10min, and the total mass of the emulsion and centrifuge tube after removing the leaked oil was recorded as m2 (g). Oil loss (%) = (m1-m2) / m0 × 100%. The freeze-thaw stability results of the emulsions are shown in Table 1.

[0082] Method for determining the retention rate of curcumin in emulsions after freeze-thaw cycles: The emulsion ink materials prepared in Examples 1-3 and Comparative Examples 1-4 were respectively placed in 30 mL glass vials, frozen at -22°C for 24 h, and then thawed at 25°C for 4 h. This cycle was repeated 3 times. The retention rate of curcumin in each emulsion sample was determined according to the method in Experimental Example 4. The results of the curcumin retention rate are shown in Table 2.

[0083] Table 1. Oil loss rates of emulsions from Examples 1-3 and Comparative Examples 1-4 after multiple freeze-thaw cycles.

[0084]

[0085] As shown in Table 1, comparing Comparative Example 1 and Comparative Example 2, the addition of polysaccharides significantly improved the freeze-thaw stability of the high internal phase emulsion. This may be because the freeze-thaw stability of HIPEs is related to particle size. A comprehensive comparison of the results from Examples 1-3 and Comparative Examples 1-4 demonstrates that the freeze-thaw stability of the high internal phase emulsion prepared by combining soybean protein isolate treated with a pulsed electric field with a polysaccharide solution is significantly improved. This is because the pulsed electric field improves the surface charge of the soybean protein isolate, allowing for stronger electrostatic interactions with the polysaccharide charge to stabilize the solution, achieve smaller emulsion droplet sizes, and minimize aggregation, thereby improving freeze-thaw stability.

[0086] Table 2. Curcumin retention rates of emulsions from Examples 1-3 and Comparative Examples 1-4 after multiple freeze-thaw cycles.

[0087]

[0088] As shown in Table 2, compared with the emulsion ink materials prepared in Comparative Examples 1-4, the emulsions prepared in Examples 1-3 of this invention can effectively retain curcumin. After three freeze-thaw cycles, the curcumin retention rate is still as high as 86.32%-91.63%, with Example 1 showing the best curcumin retention rate. This may be because in Comparative Examples 1-3, the emulsion leakage was more severe, and after leakage, more curcumin came into direct contact with oxygen, causing oxidation and loss of curcumin.

[0089] The experimental results above demonstrate that the high internal phase emulsion ink material prepared by this invention exhibits high stability after freeze-thaw storage and a high retention rate of bioactive substances. It effectively encapsulates bioactive substances, better achieving the slow-release and targeted transport of bioactive components, and improving the emulsion's retention capacity of internal phase substances under freeze-thaw conditions. Therefore, the high internal phase emulsion ink material prepared by this invention has enormous application prospects and development potential in the preparation of 3D printed functional foods, and can also provide new technical directions and support for 3D printed functional foods.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art can make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for preparing a high internal phase emulsion ink material, characterized in that, Includes the following steps: (1) The soybean protein isolate solution is subjected to pulsed electric field treatment, and then polysaccharide solution is added and stirred to obtain protein-polysaccharide composite solution, with the protein-polysaccharide composite solution as the aqueous phase; separately, bioactive substances are mixed evenly with vegetable oil as the oil phase; wherein, the polysaccharide used in the polysaccharide solution is one of high methoxyl pectin, xanthan gum, and konjac mannan; (2) The aqueous phase and oil phase are mixed and then sheared at high speed to obtain a high internal phase emulsion ink material; In step (1), the process conditions for pulsed electric field treatment are as follows: pulse intensity is 20~40kV / cm, pulse width is 40~60μs, pulse frequency is 0.8k~1.2kHz, and flow rate is 8~12mL / min; the mass concentration of the soy protein isolate solution is 30~50mg / mL; the mass concentration of the polysaccharide solution is 15~25mg / mL; and the mixing volume ratio of the soy protein isolate solution to the polysaccharide solution is (0.8~1.2)∶(0.8~1.2).

2. The method for preparing the high internal phase emulsion ink material according to claim 1, characterized in that, In step (1), the stirring speed is 300~500 r / min and the stirring time is 1~3 h.

3. The method for preparing the high internal phase emulsion ink material according to claim 1 or 2, characterized in that, In step (1), the bioactive substance is one of curcumin, carotenoids, and astaxanthin; the mass concentration of the bioactive substance in the oil phase is 0.05%~0.2%.

4. The method for preparing the high internal phase emulsion ink material according to claim 1 or 2, characterized in that, In step (1), the vegetable oil is one of soybean oil, corn oil, and peanut oil.

5. The method for preparing the high internal phase emulsion ink material according to claim 1 or 2, characterized in that, In step (2), the volume ratio of the aqueous phase to the oil phase is 1:(3~5).

6. The method for preparing the high internal phase emulsion ink material according to claim 1 or 2, characterized in that, In step (2), the rotation speed of the high-speed shearing is 10000~12000 r / min, and the high-speed shearing time is 3~6 min.

7. A high internal phase emulsion ink material prepared by the preparation method according to any one of claims 1 to 6.

8. An application of the high internal phase emulsion ink material as described in claim 7, characterized in that, Application of ink materials in 3D printed food.

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