A composite emulsion gel with good rigid-flexible structure and a preparation method and application thereof

Abstract

This invention discloses a composite emulsion gel with a good rigid-flexible structure, its preparation method, and its applications, belonging to the field of food processing and nutrient delivery technology. The emulsion gel prepared using the method provided by this invention forms a dense, uniform, and finely distributed three-dimensional network structure within the gel, significantly reducing oil droplet flocculation and aggregation, improving the long-term stability of the emulsion gel, and achieving efficient release and delivery of fatty acids and fat-soluble active substances. It also possesses high nutritional and probiotic value; meets the IDDSI Level 5 swallowing safety standard, has good biocompatibility, and is safe and non-toxic; the provided preparation method is mild, requires no chemical cross-linking agents, and has high safety; it also solves the technical problems of rigid texture, poor swallowing compatibility, and low nutrient delivery efficiency of specialty oils rich in polyunsaturated fatty acids during the structuring process, promoting the industrialization of functional soft materials in the field of personalized nutrition manufacturing.

Description

Technical Field

[0001] This invention relates to the field of food processing and nutrient delivery technology, and in particular to a composite emulsion gel with a good rigid-flexible structure, its preparation method, and its application. Background Technology

[0002] With the accelerating aging of the global population, dysphagia has become a major public health issue, impacting the quality of life and nutritional health of the elderly. Due to decreased chewing and swallowing abilities, patients with dysphagia often face difficulties eating, an increased risk of aspiration pneumonia, and insufficient intake of nutrients such as protein and lipids. Therefore, developing specialized foods that are safe, easy to swallow, and have appropriate nutrient density is of significant practical importance.

[0003] Emulsion gels, as semi-solid systems combining the properties of emulsions and gels, consist of an oil phase, an aqueous phase, and emulsifiers / gelling agents. They can effectively encapsulate fat-soluble bioactive substances and, by modulating their microstructure, achieve precise control over texture properties and digestive behavior. In recent years, 3D printing technology, especially direct ink writing (DIW) additive manufacturing, has provided new technological avenues for developing personalized diets for patients with dysphagia, as it allows for the design of food shape, texture, and nutritional composition on demand.

[0004] However, existing emulsion gel systems still have shortcomings in terms of printability, swallowing safety, and nutrient delivery efficiency; there is an urgent need to develop functional gel materials with good rheological properties, soft texture, and high stability through reasonable component design.

[0005] Soy protein isolate (SPI) is widely used as a scaffold material for plant-based emulsion gels due to its excellent emulsifying and gelling properties and high nutritional value. However, emulsion gels stabilized solely by SPI are prone to oil droplet aggregation and network collapse during processing or storage, thus limiting their application performance. Summary of the Invention

[0006] The purpose of this invention is to provide a composite emulsion gel with a good rigid-flexible structure, its preparation method and application, so as to solve the problems of poor printability, rigid texture, poor swallowability and low nutrient delivery efficiency of existing emulsion gel systems, and insufficient utilization of soy protein isolate performance.

[0007] To achieve the above objectives, the present invention provides a composite emulsion gel with a good rigid-flexible structure, which is prepared from the following raw materials in parts by weight: 45-50 parts vegetable oil, 4-6 parts soy protein isolate, 0.1-0.5 parts carrageenan, 0.1-0.5 parts inulin, and 40-50 parts water.

[0008] Preferably, the mass ratio of carrageenan to inulin is 1:(1~3); the total mass of carrageenan and inulin accounts for 0.2%~1.0% of the total mass of the composite emulsion gel.

[0009] Preferably, the vegetable oil is an oil containing polyunsaturated fatty acids, and is one or more of flaxseed oil, sesame oil, safflower oil, perilla seed oil, and walnut oil.

[0010] Preferably, the composite emulsion gel encapsulates active ingredients.

[0011] On the other hand, the present invention also provides a method for preparing a composite emulsion gel with a good rigid-flexible structure, the steps of which are as follows: S1. Prepare soybean protein isolate dispersion; S2. Add carrageenan and inulin to the soybean protein isolate dispersion prepared in S1, adjust the pH, and stir the reaction to obtain a composite emulsion gel with a good rigid-flexible structure.

[0012] Preferably, in step S1, the soy protein isolate dispersion is prepared by dissolving soy protein isolate in deionized water, with a mass concentration of 1.5 mg / mL to 3.5 mg / mL; in step S2, the pH is adjusted to 7.0, and the mixture is stirred at 25°C for 25 min to 40 min.

[0013] Preferably, the active ingredient is encapsulated in the composite emulsion gel with a good rigid-flexible structure, and the steps are as follows: The active ingredient is dissolved in vegetable oil and then added to a composite emulsion gel with a good rigid-flexible structure. After high-speed homogenization and refrigeration, a composite emulsion gel with encapsulated active ingredient and a good rigid-flexible structure is obtained. The mass of the active ingredient is 0.1% to 0.5% of the mass of the vegetable oil. The refrigeration is carried out at 4°C for 12 to 48 hours. The high-speed homogenization speed is 12000 r / min to 18000 r / min and the time is 3 min to 5 min.

[0014] On the other hand, the present invention also provides the application of the composite emulsion gel with good rigid-flexible structure prepared by the preparation method described above in the preparation of 3D printed personalized nutritional foods.

[0015] A method for preparing 3D printed personalized nutritional foods using the composite emulsion gel with good rigid-flexible structure prepared by the above preparation method. The 3D printing parameters are: temperature 25℃~35℃, speed 15mm / s, and nozzle inner diameter 0.26mm.

[0016] The application of the composite emulsion gel with good rigid-flexible structure prepared by the above method in the preparation of food for people with dysphagia.

[0017] Therefore, the present invention provides a composite emulsion gel with a good rigid-flexible structure, its preparation method, and its application, the specific technical effects of which are as follows: (1) The composite emulsion gel system provided by the present invention utilizes the rigid helical aggregation network of carrageenan (KC) and the flexible chain filling effect of inulin to form a dense three-dimensional network structure inside the gel and construct a continuous protein-polysaccharide composite interface film at the oil-water interface; it significantly reduces the flocculation and aggregation of oil droplets and improves the long-term stability of the emulsion gel; and through the digestive regulation mechanism of "slow release without inhibition", it realizes the efficient release and delivery of fatty acids and fat-soluble active substances, providing a solid technical foundation for personalized nutritional intervention for people with dysphagia; it can also structure characteristic oils rich in polyunsaturated fatty acids to improve the nutritional value of products; (2) The emulsion gel prepared by the method provided in this invention, through the synergistic network construction mechanism of "rigid skeleton + flexible filling", ensures IDSI level 5 swallowing safety while achieving efficient encapsulation of fat-soluble active substances and ideal digestive characteristics of "slow release without inhibition". It solves the technical problems of rigid texture, poor swallowing compatibility and low nutrient delivery efficiency of characteristic oils rich in polyunsaturated fatty acids during the structuring process, and promotes the industrialization of functional soft materials in the field of personalized nutrition manufacturing. (3) The emulsion gel prepared by the method provided in this invention has a dense and uniform gel network, small and uniform oil droplet distribution, and a porosity as low as 29.7%. The storage modulus is 37% to 67% higher than that of the binary system (soy protein isolate-carrageenan). Samples with a concentration range of 0.4% to 0.8% all meet the IDDSI Level 5 swallowing safety standard. In the spoon tilt test, it can easily slide off with little residue. In the fork drop test, it maintains its shape and does not drip. In the fork pressure test, there is no whitening of the fingertips. (4) The emulsion gel prepared by the method provided by the present invention uses food-grade raw materials, which are biocompatible, safe and non-toxic. The preparation process is mild and does not require chemical cross-linking agents, which meets the food safety requirements. Inulin (IN) is a natural functional dietary fiber with prebiotic function. It can further endow the product with health benefits such as regulating intestinal flora and promoting mineral absorption. It can be widely used in the fields of special dietary foods, functional foods and personalized nutrition manufacturing.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a SEM image of the composite emulsion gel with a good rigid-flexible structure prepared in Example 1 of the effect test 1 of this invention; the magnification is 2500x; where (A) is 0.2%-SKI; (B) is 0.4%-SKI; (C) is 0.6%-SKI; (D) is 0.8%-SKI; (E) is 1.0%-SKI; (F) is the porosity result diagram; Figure 2 This is a CLSM image from the effect test 1 of this invention; the magnification is 40x; where LOEG is the composite emulsion gel with a good rigid-flexible structure prepared in Example 1; SOEG is the composite emulsion gel with a good rigid-flexible structure prepared in Example 2; Figure 3 These are the results of the IDDSI dysphagia assessment in the efficacy test 2 of this invention; where (A) is SKI-L; (B) is SKI-S; Figure 4 This is a graph showing the protein hydrolysis and fatty acid release rates in test 3 of the present invention; where (A) is the composite emulsion gel with a good rigid-flexible structure prepared in Example 1; and (B) is the composite emulsion gel with a good rigid-flexible structure prepared in Example 1. Figure 5 This is a graph showing the vitamin D3 encapsulation efficiency in test 3 of the present invention; Figure 6 These are images of the finished products 3D printed using different emulsion gels in the effect test 4 of this invention; where LO is the composite emulsion gel with a good rigid-flexible structure prepared in Example 1; and SSO is the composite emulsion gel with a good rigid-flexible structure prepared in Example 2. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] To make the objectives, technical solutions, and advantages of this application clearer, more thorough, and more complete, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. The following detailed descriptions are all illustrations of embodiments, intended to provide further detailed explanation of the present invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0023] The instruments, equipment, reagents and materials used in the embodiments were all obtained through commercial means; the methods and steps not described in detail in the embodiments are all conventional techniques in the art.

[0024] Example 1 The specific steps for preparing a composite emulsion gel with a good rigid-flexible structure are as follows: S1. Prepare soybean protein isolate dispersion.

[0025] Take 20g of soy protein isolate with a purity ≥98%, dissolve it in an appropriate amount of deionized water, and then make up the volume to 200mL with deionized water to prepare a soy protein isolate dispersion with a mass concentration of 100mg / mL.

[0026] S2. Preparation of soybean protein isolate-carrageenan-inulin complex.

[0027] Take 15g of the soy protein isolate dispersion prepared in step S1, disperse a quantitative amount of carrageenan and inulin in it, then adjust the pH to 7.0 with 0.5mol / L dilute hydrochloric acid, and stir the mixture at 300rpm for 30min at 25℃ to obtain the soy protein isolate-carrageenan-inulin complex.

[0028] S3. Prepare composite emulsion gels with good rigid-flexible structure.

[0029] Dissolve 0.15g of vitamin D3 in 15g of flaxseed oil (final concentration 0.5%), then mix with the soy protein isolate-carrageenan-inulin complex prepared in step S2, homogenize at 12000rpm for 5min, transfer to a 30mL mold, and store at 4℃ for 24 hours to obtain a composite emulsion gel with a good rigid-flexible structure, denoted as SKI-L.

[0030] The amount of each component added is shown in Table 1.

[0031] Table 1 Information on the amount of each component added

[0032] Example 2 The specific steps for preparing a composite emulsion gel with a good rigid-flexible structure are as follows: S1. Prepare soybean protein isolate dispersion.

[0033] Take 16g of soy protein isolate with a purity ≥98%, dissolve it in an appropriate amount of deionized water, and then make up the volume to 200mL with deionized water to prepare a soy protein isolate dispersion with a mass concentration of 100mg / mL.

[0034] S2. Preparation of soy protein isolate-carrageenan-inulin complex. Take 15g of the soy protein isolate dispersion prepared in step S1, disperse a quantitative amount of carrageenan and inulin in it, then adjust the pH to 7 with 0.5mol / L dilute hydrochloric acid, and stir the mixture at 300rpm for 30min at 25℃ to obtain the soy protein isolate-carrageenan-inulin complex.

[0035] S3. Prepare composite emulsion gels with good rigid-flexible structure.

[0036] Dissolve 0.15g of vitamin D3 in 15g of sesame oil, then mix it with the soy protein isolate-carrageenan-inulin complex prepared in step S2. Homogenize at 12000rpm for 5min, then transfer to a 30mL mold and store at 4℃ for 24 hours to obtain a composite emulsion gel with a good rigid-flexible structure, denoted as SKI-S.

[0037] The amount of each component added is shown in Table 2.

[0038] Table 2 Information on the amount of each component added

[0039] Example 3 The specific steps for preparing a composite emulsion gel are as follows: S1. Prepare soybean protein isolate dispersion.

[0040] Take 20g of soy protein isolate with a purity ≥98%, dissolve it in an appropriate amount of deionized water, and then make up the volume to 200mL with deionized water to prepare a soy protein isolate dispersion with a mass concentration of 100mg / mL.

[0041] S2. Preparation of soybean protein isolate-carrageenan-inulin complex.

[0042] Take 15g of the soy protein isolate dispersion prepared in step S1, disperse a quantitative amount of carrageenan and inulin in it, then adjust the pH to 7.0 with 0.5mol / L dilute hydrochloric acid, and stir the mixture at 300rpm for 30min at 25℃ to obtain the soy protein isolate-carrageenan-inulin complex.

[0043] S3. Preparation of composite emulsion gel. Dissolve 0.21g of vitamin D3 in 15g of linseed oil (final concentration 0.7%), then mix with the soy protein isolate-carrageenan-inulin complex prepared in step S2, homogenize at 12000rpm for 5min, and then refrigerate at 4℃ for 24 hours to obtain composite emulsion gel, denoted as SKI.

[0044] Comparative Example 1 A composite emulsion gel was prepared using the same steps as in Example 1, except that inulin was not added. This gel is designated as SK.

[0045] Comparative Example 2 A composite emulsion gel was prepared using the same steps as in Example 1, except that the oil phase was sesame oil.

[0046] Comparative Example 3 A composite emulsion gel was prepared using the same steps as in Example 1, except that vitamin D3 was not added.

[0047] Effect Test 1 The microstructure of the composite emulsion gels with good rigid-flexible structures prepared in Examples 1 and 2 was observed, as follows: (1) Scanning electron microscopy (SEM) image of the composite emulsion gel with good rigid-flexible structure prepared in Example 1 is shown below. Figure 1 As shown, at a magnification of 2500x, the microstructure and pore distribution of the composite emulsion are revealed. The SKI emulsion with added inulin exhibits a smoother surface, a denser microstructure, higher cross-linking degree, and smaller, more regular pores. The porosity results of the samples are shown below. Figure 1 The F, 0.6% SKI-L, exhibits the smallest pore size and the most robust proteoglycan network structure, at 29.7%. Overall, this indicates that appropriate addition of total polysaccharide can effectively improve the stability of the microstructure of the emulsion gel.

[0048] (2) Laser confocal scanning microscopy (CLSM) images of the composite emulsion gels with good rigid-flexible structures prepared in Examples 1 and 2 are shown below. Figure 2 As shown, the green fluorescence is labeled with fluorescein isothiocyanate (FITC) dye, representing the aqueous phase region. Compared with the control sample (SK) without inulin, the sample with added inulin (SKI) exhibits a more continuous and uniform aqueous phase region, and the green fluorescent network is more dense, indicating that the addition of inulin promotes the formation and uniform distribution of the aqueous phase network structure. When the total concentration of gelling agent is 0.2%-0.4%, the oil droplet size is relatively large, and the distribution uniformity needs to be improved. 0.6%-SKI-L shows the optimal microstructure, with the smallest oil droplet size, the most uniform distribution, and the most continuous and dense protein-polysaccharide network structure.

[0049] Effect Test 2 The compatibility of the composite emulsion gels with good rigid-flexible structures prepared in Examples 1 and 2 with dysphagia was evaluated as follows: Approximately 2g of the composite emulsion gels with good rigid-flexible structures prepared in Examples 1 and 2 were taken respectively. Following the framework of the International Initiative for Standardization of Diets for Dysphagia (IDDSI), the texture of the emulsion gels was tested using a standard fork (4mm tooth spacing) and a standard spoon. (1) Spoon tilting test. Place the sample on a standard spoon (washed with anhydrous ethanol and air-dried naturally), tilt the spoon slowly, and observe the sample slippage and residue on the spoon surface. If the sample does not slip, you can gently shake your arm downwards.

[0050] The results are as follows Figure 3 As shown, the 0.2% and 1.0% emulsion gels (SKI-L and SKI-S) left a large amount of sample residue on the spoon surface, indicating excessive viscosity and increasing the risk of aspiration and choking in patients with dysphagia. In contrast, the 0.4%, 0.6%, and 0.8% emulsion gels (SKI-L and SKI-S) showed excellent viscoelasticity and potential as a food for patients with dysphagia in the spoon tilt test.

[0051] (2) Fork drip test. Place the sample on a standard dinner fork (washed with anhydrous ethanol and air-dried) and observe whether the sample retains its shape and does not drip.

[0052] The results are as follows Figure 3 As shown, all samples retained their original shape on the fork without dripping after being picked up, indicating that all samples had good cohesion and plasticity.

[0053] (3) Fork pressure test. All tests were performed by the same experimenter, who gradually applied pressure to the sample surface using the tines of a standard dinner fork and observed whether the fingertips turned white.

[0054] The results are as follows Figure 3 As shown, in the fork compression test, none of the samples exhibited fingertip whitening, indicating that the samples had a moderately soft texture and were easily broken into boluses after being compressed by the tongue and palate in the oral cavity, demonstrating their potential for preparing food suitable for patients with dysphagia. In summary, the 0.4%–0.8% samples (SKI-L and SKI-S) all met the IDDSI Grade 5 standard. The emulsion gelation phenomenon was consistent between SKI-L and SKI-S.

[0055] Effect Test 3 The vitamin D3 encapsulation efficiency of the composite emulsion gels with good rigid-flexible structures prepared in Examples 1 and 2, and the body's ability to digest the prepared emulsion gels, were investigated as follows: (1) Prepare materials.

[0056] Vitamin D3 was a solid powder (purchased from Beijing Innocare Technology Co., Ltd., purity 98%); the emulsion gels were SKI-L and SKI-S prepared in Examples 1 and 2, referred to as samples in the method description; the methods for preparing simulated saliva, simulated gastric juice, and simulated intestinal juice are as follows: Simulated saliva: Dissolve 30 mg of mucin in 10 mL of electrolyte solution (containing 1 g / L calcium chloride + 6.5 g / L sodium chloride) to make the final concentration of mucin 3 g / L, and adjust the pH to 6.8 with 0.1 M hydrochloric acid.

[0057] Simulated gastric juice: Dissolve NaCl in deionized water (final NaCl concentration 2g / L), adjust the pH to 2.0 with 0.05M HCl, then add pepsin (final concentration 3.2mg / mL) and dissolve completely.

[0058] Simulated intestinal fluid: Pig bile salts (final concentration 20 mg / mL), NaCl (final concentration 6.8 mg / mL), and CaCl2 (final concentration 1.1 mg / mL) were dissolved in deionized water in sequence. Then, lipase (final concentration 24 g / L) and trypsin (24 g / L) were added. After complete dissolution, the pH was adjusted to 7.0 with 0.05 M sodium hydroxide.

[0059] (2) Examine the degree of protein hydrolysis.

[0060] Oral administration period: Mix 0.5g of sample with SSF (5mL), adjust the pH to 6.8 with 0.05mol / L NaOH solution, and heat and stir at 37℃ for 10min.

[0061] Gastric digestion stage: 10 mL of SGF was added to 0.5 g of sample, and the pH was adjusted to 2.0 with 0.05 M hydrochloric acid. The mixture was heated and stirred at 37 °C and 300 rpm / min for 2 hours. Aliquots were collected every 30 min and immediately subjected to heat treatment at 100 °C for 5 min to inactivate the enzyme. The degree of hydrolysis of the emulsion gel samples was analyzed using the OPA method. The samples were stored at 4 °C, and during the determination, they were dissolved in a 40 °C water bath to a liquid state. The samples were centrifuged at 10,000 rpm for 10 min. 400 μL of the supernatant was mixed with 3 mL of OPA reagent (phthalaldehyde-dithiothreitol-sodium tetraborate system), and reacted at room temperature in the dark for 2 min. The absorbance was measured at 340 nm. The degree of protein hydrolysis (DH) was calculated using the following formulas I and II: (Formula I); (Formula II); Wherein, DH represents the degree of protein hydrolysis; ; ; .

[0062] The results are as follows Figure 4 As shown, linseed oil-based or sesame oil-based emulsion gels with added inulin have a denser gel network, which to some extent affects the diffusion of digestive enzymes in the gel matrix, thus facilitating further absorption and utilization of protein in the small intestine. Furthermore, as a soluble dietary fiber, inulin can resist the enzymatic breakdown process of pepsin, thereby promoting further absorption and utilization of protein in the small intestine.

[0063] (3) Determination of free fatty acid release rate.

[0064] Small intestinal digestion stage: Porcine bile salt solution was added to terminate the gastric phase. The pH of the mixture was adjusted to 7.0 using 0.05 mol / L NaOH solution to begin simulated intestinal digestion. An equal volume of SIF was added, and the mixture was incubated at 37°C and 300 rpm for 2 hours. The pH of the reaction system was maintained at 7.0 using 0.05 M NaOH solution, and the volume of NaOH consumed was recorded to calculate free fatty acids (…). The free fatty acid (FFA) release rate, which characterizes the degree of fat breakdown, is calculated using the formula shown in Equation III: (Formula III) Where FFA (%) represents the free fatty acid release rate; The volume of NaOH is in mL. The molar concentration of NaOH is expressed in mol / L. The average molar mass of the oil phase (g / mol); The total mass (g) of the emulsion gel.

[0065] The results are as follows Figure 4 As shown, after lipid digestion in the small intestine, the dense network structure effectively slows down the diffusion of digestive enzymes in the gel matrix, resulting in a sustained-release effect. Furthermore, the uniformly dispersed fine oil droplets increase the contact interface between lipids and lipases, leading to a higher final release rate of free fatty acids compared to liquid oil, reaching up to 68.2%. The synergistic effect of these three factors achieves the ideal digestive characteristic of "sustainable release without inhibition."

[0066] (4) Determination of vitamin D3 encapsulation efficiency.

[0067] Take 1.1 g of emulsion gel sample, add 5 mL of n-hexane, vortex extract at room temperature for 10 min, then centrifuge at 10000 rpm for 10 min, and collect the upper organic phase; repeat the extraction 3 times, combine the organic phases and make up to 25 mL with n-hexane, measure the absorbance at 264 nm, and calculate the encapsulation efficiency using the following formula IV: (Form IV) Where E represents the encapsulation efficiency of vitamin D3; A represents the total amount of vitamin D3 (mg); and U represents the total amount of unencapsulated vitamin D3 (mg).

[0068] The results are as follows Figure 5 As shown, samples containing 0.4%–0.8% SKI-L and SKI-S gradually formed a denser and more uniform gel network structure. This structure can act as a physical barrier, effectively isolating vitamin D3 from external factors such as oxygen and light, thereby reducing its degradation and achieving a high encapsulation efficiency of 86.64%.

[0069] Effect Test 4 The 3D printing performance of the composite emulsion gels with good rigid-flexible structures prepared in Examples 1 and 2 was examined, as follows: The printing was performed using the SenGong AutoBio ink direct-write 3D printer. The model was selected using MakerWorld software, and the 3D model was sliced ​​and code generated using Ultimaker Cura software. The printing parameters were as follows: print cylinder temperature 25℃, square dimensions 20mm×20mm×5mm, printing speed 15mm / s, print head inner diameter 0.26mm, and infill density 50%.

[0070] The results are as follows Figure 6 As shown, all emulsion gel samples were extruded continuously and smoothly during the 3D printing process. The 3D printed products had smooth surfaces and clear printing layers, demonstrating excellent shape retention and structural integrity. All samples showed potential for 3D printing complex models, without any blurring or collapse due to material properties. Except for the 0.8% SKI-L and SKI-S samples, which had larger printing errors, the printed products of the remaining samples all exhibited high dimensional accuracy, with the absolute value of the error controlled within 1.2%.

[0071] Therefore, the emulsion gel prepared by the method provided in this invention forms a dense, uniform, and finely distributed three-dimensional network structure within the gel, significantly reducing oil droplet flocculation and aggregation, improving the long-term stability of the emulsion gel, and achieving efficient release and delivery of fatty acids and fat-soluble active substances. It also has high nutritional and probiotic value; meets the IDDSI Level 5 swallowing safety standard, has good biocompatibility, and is safe and non-toxic; the preparation method provided is mild, requires no chemical cross-linking agents, and has high safety; it also solves the technical problems of rigid texture, poor swallowing compatibility, and low nutrient delivery efficiency of characteristic oils rich in polyunsaturated fatty acids during the structuring process, promoting the industrialization of functional soft materials in the field of personalized nutrition manufacturing.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A composite emulsion gel with a good rigid-flexible structure, characterized in that, It is prepared from the following raw materials in parts by weight: 45-50 parts vegetable oil, 4-6 parts soy protein isolate, 0.1-0.5 parts carrageenan, 0.1-0.5 parts inulin, and 40-50 parts water.

2. The composite emulsion gel with a good rigid-flexible structure according to claim 1, characterized in that: The mass ratio of carrageenan to inulin is 1:(1~3); the total mass of carrageenan and inulin accounts for 0.2%~1.0% of the total mass of the composite emulsion gel.

3. The composite emulsion gel with a good rigid-flexible structure according to claim 1, characterized in that: The vegetable oil is an oil containing polyunsaturated fatty acids, and is one or more of flaxseed oil, sesame oil, safflower oil, perilla seed oil, and walnut oil.

4. The composite emulsion gel with a good rigid-flexible structure according to claim 1, characterized in that: The active ingredients are encapsulated in the composite emulsion gel.

5. A method for preparing a composite emulsion gel with a good rigid-flexible structure as described in any one of claims 1 to 4, characterized in that, The steps are as follows: S1. Prepare soybean protein isolate dispersion; S2. Add carrageenan and inulin to the soybean protein isolate dispersion prepared in S1, adjust the pH, and stir the reaction to obtain a composite emulsion gel with a good rigid-flexible structure.

6. The method for preparing a composite emulsion gel with a good rigid-flexible structure according to claim 5, characterized in that: The soy protein isolate dispersion in S1 is prepared by dissolving soy protein isolate in deionized water at a concentration of 1.5 mg / mL to 3.5 mg / mL; in S2, the pH is adjusted to 7 and stirred at 25°C for 25 min to 40 min.

7. The method for preparing a composite emulsion gel with a good rigid-flexible structure according to claim 5, characterized in that, The active ingredients are encapsulated in the composite emulsion gel with a good rigid-flexible structure, and the steps are as follows: The active ingredient is dissolved in vegetable oil and then added to a composite emulsion gel with a good rigid-flexible structure. After high-speed homogenization and refrigeration, a composite emulsion gel with encapsulated active ingredient and a good rigid-flexible structure is obtained. The mass of the active ingredient is 0.1% to 0.5% of the mass of the vegetable oil. The refrigeration is carried out at 4°C for 12 to 48 hours. The high-speed homogenization speed is 12000 to 18000 r / min and the time is 3 to 5 min.

8. The application of the composite emulsion gel with good rigid-flexible structure prepared by the preparation method according to any one of claims 6-7 in the preparation of 3D printed personalized nutritional foods.

9. A method for preparing 3D-printed personalized nutritional foods using a composite emulsion gel with a good rigid-flexible structure prepared by the preparation method according to any one of claims 6-7, characterized in that, The parameters for 3D printing are: temperature 25℃~35℃, speed 15mm / s, and nozzle inner diameter 0.26mm.

10. The application of the composite emulsion gel with a good rigid-flexible structure prepared by the preparation method according to any one of claims 6-7 in the preparation of food for people with dysphagia.

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