Beta-glucan-quinoa protein interpenetrating double-network gel as well as preparation method and application thereof

Abstract

The invention provides beta-glucan-quinoa protein interpenetrating double-network gel as well as a preparation method and application of the beta-glucan-quinoa protein interpenetrating double-network gel. The beta-glucan-chenopodium quinoa protein interpenetrating double-network gel is prepared from the following raw materials: chenopodium quinoa protein, beta-glucan and water, the concentration of the chenopodium quinoa protein in the gel is 5 to 25 percent, and the concentration of the beta-glucan in the gel is 3 to 5 percent. The beta-glucan is oat beta-glucan or barley beta-glucan, and the beta-glucan is beta-glucan or barley beta-glucan. The preparation method of the beta-glucan-chenopodium quinoa protein interpenetrating double-network gel comprises the following steps: uniformly mixing the chenopodium quinoa protein, the beta-glucan and water, heating in a water bath, carrying out gelation reaction, cooling after the reaction, and refrigerating and storing to obtain the beta-glucan-chenopodium quinoa protein interpenetrating double-network gel. The quinoa protein and the beta-glucan are used as raw materials, the adaptability is high, the enhanced double-network gel can be prepared under the neutral condition, and the stability is high. The gel provided by the invention has excellent water binding capacity and gel strength, and is relatively high in antioxidant activity.

Description

Technical Field

[0001] This application belongs to the field of food processing technology, specifically relating to a β-glucan-quinoa protein interpenetrating double network gel, its preparation method, and its application. Background Technology

[0002] Against the backdrop of a growing global aging population, the steady increase in the number of elderly people brings numerous health challenges, among which age-related decline in swallowing function leading to dysphagia is particularly prominent (Calligaris et al., 2022). This physiological change not only affects food intake but can also lead to food aspiration into the trachea, causing serious consequences such as choking and aspiration pneumonia (Liu et al., 2023). It is noteworthy that dysphagia is not limited to the elderly; it is also prevalent among stroke patients, Parkinson's disease patients, and Alzheimer's disease patients (Schmidt et al., 2021), making the development of specific foods for people with dysphagia especially important. Currently, texture-modified foods have received widespread attention as a solution for dysphagia. Texture-modified foods refer to foods with a soft texture or small particles that can be easily mixed and broken down in the mouth by compression of the tongue and palate without chewing (Ishihara et al., 2013). The simplest texture-modified food processing techniques involve making the food into a puree, chopping, or softening it to achieve a soft texture. However, these products often lack sensory or taste appeal, which may lead patients to refuse consumption or reduce their intake (Liu et al., 2024). Therefore, how to enhance the sensory and taste appeal of food while maintaining its soft texture has become an urgent problem to be solved. In recent years, 3D printing technology has shown great potential in the development of foods for those with difficulty swallowing due to its advantages such as personalized nutrition, customized texture, and creation of appetite structures (Liu et al., 2023). Using 3D printing technology, it is possible to create foods with diverse and appealing appearances while retaining their original texture, greatly increasing the attractiveness of foods for those with difficulty swallowing. In addition, 3D printing allows for the addition of essential nutrients during the printing process, ensuring that these special diets are nutritionally adequate (Liu et al., 2024). However, the application of 3D printing technology in foods for those with difficulty swallowing requires the development of suitable soft materials.

[0003] Plant proteins have become a popular ingredient in 3D-printed diets for patients with dysphagia due to their high nutritional value, ease of access, and environmental friendliness (Liu et al., 2024). Soft gels obtained by utilizing the gelling properties of proteins are an important source of foods for patients with dysphagia (L. Li et al., 2025). Quinoa protein, as an emerging protein source with a balanced amino acid composition, is not only nutritious but also gluten-free, making it suitable for patients with celiac disease (Xu et al., 2024). Furthermore, quinoa protein, mainly composed of 11S globulin and 2S albumin, possesses heat-induced gelation properties (Yang et al., 2022), making it an ideal source for soft gel foods. However, heat-induced gels prepared from quinoa protein under neutral conditions exhibit poor stability (Kaspchak et al., 2017), making them difficult to meet processing requirements. Therefore, there is an urgent need to develop a soft-textured, high-nutritional-value gel-type food for patients with dysphagia. Summary of the Invention

[0004] In view of this, this application provides a β-glucan-quinoa protein interpenetrating double network gel with strong gel properties, high gel strength, strong stability, and a simple and easy preparation method. It can be used to develop soft, nutritious, and 3D-printable foods for those with difficulty swallowing.

[0005] This application provides a β-glucan-quinoa protein interpenetrating double network gel, the raw materials of which include quinoa protein, β-glucan and water, wherein the concentration of quinoa protein in the gel is 5-25% and the concentration of β-glucan is 3-5%.

[0006] Preferably, the β-glucan is oat β-glucan or barley β-glucan.

[0007] This application also provides a method for preparing the above-mentioned β-glucan-quinoa protein interpenetrating double network gel, wherein the quinoa protein, the β-glucan and water are mixed evenly and heated in a water bath to carry out a gelation reaction, and after the reaction is cooled and stored under cold storage, a β-glucan-quinoa protein interpenetrating double network gel is obtained.

[0008] Preferably, the water bath heating temperature is 60~90°C.

[0009] Preferably, the cooling process includes ice bath cooling.

[0010] Preferably, the refrigeration temperature does not exceed 4°C and the time is 12~24h.

[0011] This application also provides the application of the above-mentioned β-glucan-quinoa protein interpenetrating double network gel in the preparation of dysphagia food, wherein the β-glucan-quinoa protein interpenetrating double network gel is prepared by 3D printing through extrusion to obtain dysphagia food.

[0012] Preferably, the amount of β-glucan added is 4-5%.

[0013] Preferably, the food causing dysphagia is classified as level 4.

[0014] This application also provides a dysphagia food for IDDSI level 4, which is prepared by 3D printing of the above-mentioned β-glucan-quinoa protein interpenetrating double network gel.

[0015] Compared with existing technologies, this application uses quinoa protein and β-glucan as raw materials, which has high compatibility and can produce an enhanced double-network gel under neutral conditions with strong stability. The gel of this application has excellent water retention and gel strength, and also has high antioxidant activity.

[0016] The preparation method of this application can obtain strong gel properties through simple mixing, heating and cooling, and has the advantages of being simple and easy to operate, having high gel strength and strong stability.

[0017] This application relates to the preparation of foods for dysphagia, which are high in protein, gluten-free, and have antioxidant properties, meeting the nutritional and safety needs of the elderly and patients with specific diseases (such as celiac disease). It also provides a novel plant-based ink formulation for 3D printing foods for dysphagia, supporting personalized nutritional design and enhanced sensory experience, and offering new ideas for the application of 3D printing technology in the field of foods for dysphagia. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The images show the appearance of different materials. In the figures, a is β-glucan gel, b is quinoa protein gel, and c is β-glucan-quinoa protein interpenetrating double network gel.

[0020] Figure 2 Results of tests on different gel properties.

[0021] Figure 3 SEM and CLSM images of different gels.

[0022] Figure 4 The results show the antioxidant properties of different gels.

[0023] Figure 5 To evaluate the 3D printing performance of different gels.

[0024] Figure 6 The results of swallowing disorder tests for different gels. Detailed Implementation

[0025] The present application will be further described in detail below with reference to specific embodiments. The embodiments given are only for illustrating the present application and are not intended to limit the scope of the present application.

[0026] A β-glucan-quinoa protein interpenetrating double network gel, the raw materials of which include quinoa protein, β-glucan and water, wherein the concentration of quinoa protein in the gel is 5-25% and the concentration of β-glucan is 3-5%.

[0027] The presence of β-glucan significantly enhances the water-holding capacity and gel strength of quinoa protein gel, attributed to its hydrophilicity, high viscosity, and interaction with proteins. β-glucan binds to quinoa protein through non-covalent bonds (hydrogen bonds, hydrophobic interactions), promoting a transformation of the protein's secondary structure from β-sheets / random coils to α-helices / β-turns, thus increasing structural order. β-glucan fills the gaps in the protein network, forming an interpenetrating network, reducing water channels, enhancing gel stability, and preventing network destruction caused by microphase separation, resulting in a denser three-dimensional network structure. Simultaneously, β-glucan dose-dependently enhances the gel's antioxidant activity, increasing the product's health benefits. However, if the β-glucan concentration exceeds this range, it leads to network structure disruption and decreased gel performance.

[0028] The molecular structures of β-glucan from different sources vary to varying degrees. Oat β-glucan is preferred. Oat β-glucan is an active polysaccharide extracted from oats and has a variety of health benefits, such as lowering cholesterol, enhancing immunity, and preventing cancer. Among these benefits, its immunomodulatory effect may affect the immune response of the elderly and help fight common infections and inflammations in old age.

[0029] The above-described method for preparing the β-glucan-quinoa protein interpenetrating double network gel involves uniformly mixing quinoa protein, β-glucan, and water, followed by a water bath heating process to induce a gelation reaction. The preferred water bath heating temperature is 90°C for 30 minutes. After the reaction, the mixture is cooled in an ice bath and stored under refrigeration at a temperature not exceeding 4°C for 12–24 hours to obtain the β-glucan-quinoa protein interpenetrating double network gel.

[0030] Existing technologies sometimes employ high-pressure microfluidic homogenization, ultrasound-assisted enzyme cross-linking, and heating to obtain composite gels. These methods are complex, time-consuming, and energy-intensive. Some methods use chemical reagents, posing a risk of residue, while others use extreme pH values ​​that affect nutritional value. Compared to existing technologies, the preparation method described in this application is simpler and more efficient.

[0031] The application of the aforementioned β-glucan-quinoa protein interpenetrating double network gel in the preparation of dysphagia-prone foods: Specifically, the amount of β-glucan added can be 3-5%, preferably 4-5%. Dysphagia-prone foods of IDDSI grade 4 can be produced by 3D printing via extrusion. IDDSI grade 4 requires products to be free of particles, homogeneous, and have a balance between formability and flowability. The β-glucan-quinoa protein interpenetrating double network gel of this application has high gel strength, strong stability, good processing adaptability, and the material meets the IDDSI grade 4 (thick / very thick food) standard, possessing safe swallowing characteristics (no risk of adhesion, easily deformable and not prone to dripping).

[0032] Example 1 The preparation method of β-glucan-quinoa protein interpenetrating double network gel includes: dissolving 1.5g of quinoa protein and 0.5g of oat β-glucan in 10mL of water, mixing thoroughly, and stirring for 2h to fully hydrate the protein. The gelation reaction is carried out by heating in a 90℃ water bath for 30min, followed by cooling in an ice bath for 10min, and then storing at 4°C for 12h to obtain the β-glucan-quinoa protein interpenetrating double network gel, denoted as BG-5%.

[0033] Example 2 The preparation method of β-glucan-quinoa protein interpenetrating double network gel is similar to that in Example 1, except that the amount of β-glucan added is 0.4g, and the resulting β-glucan-quinoa protein interpenetrating double network gel is designated as BG-4.

[0034] Example 3 The preparation method of β-glucan-quinoa protein interpenetrating double network gel is similar to that in Example 1, except that the amount of β-glucan added is 0.3g, and the resulting β-glucan-quinoa protein interpenetrating double network gel is designated as BG-3.

[0035] Comparative Example 1 The preparation method of β-glucan-quinoa protein interpenetrating double network gel is similar to that in Example 1, except that the amount of β-glucan added is 0.2g, and the resulting β-glucan-quinoa protein interpenetrating double network gel is designated as BG-2.

[0036] Comparative Example 2 The preparation method of β-glucan-quinoa protein interpenetrating double network gel is similar to that in Example 1, except that the amount of β-glucan added is 0.1g, and the resulting β-glucan-quinoa protein interpenetrating double network gel is designated as BG-1.

[0037] Comparative Example 3 The preparation method of β-glucan-quinoa protein interpenetrating double network gel is similar to that in Example 1, except that β-glucan is not added and the resulting gel is denoted as BG-0.

[0038] I. Gel Appearance Prepare 5% β-glucan gel, 15% quinoa protein gel, and the gel from Example 1, respectively.

[0039] The results are as follows Figure 1 As shown, 5% β-glucan and 15% quinoa protein cannot form an effective gel on their own; the gel falls off when inverted, indicating weak strength. In contrast, the β-glucan-quinoa protein interpenetrating double network gel obtained in Example 1 can support the complete structure and does not fall off, demonstrating significantly improved gel strength.

[0040] II. Gel water retention Weigh approximately 5g of gel sample, equilibrate at 25°C for 30 min, and then centrifuge at 4,000g for 20 min. Water-holding capacity is calculated as the ratio of the gel weight after centrifugation to the gel weight before centrifugation.

[0041] The results are as follows Figure 2 As shown, when the amount of β-glucan added increased from 0% to 5%, the water holding capacity of the composite gel significantly increased from 78.6% to 99.3%, indicating that β-glucan can significantly increase the water-holding capacity of quinoa protein gel. On the one hand, as a hydrophilic polysaccharide, β-glucan's high viscosity allows it to adsorb and retain a large amount of water, reducing the amount of mobile water within the gel and forming a stable hydration layer, thereby reducing water outflow. On the other hand, the interaction between β-glucan and quinoa protein affects the formation of the three-dimensional gel network, thus influencing the gel's water-holding capacity.

[0042] III. Gel Strength Gel strength was evaluated using a texture analyzer equipped with a TA / 0.5 probe (TA.TOUCH, Baosheng Technology, Shanghai, China). Parameters were set as follows: pre-test speed 1.0 mm / s; test speed 2.0 mm / s; post-test speed 10.0 mm / s; distance 150 mm; trigger force 5.0 g.

[0043] The results are as follows Figure 2 As shown, the addition of β-glucan significantly increased the hardness, breaking distance, and gel strength of the composite gel, which is consistent with the improvement in water holding capacity, indicating that a stronger gel network was formed within the gel.

[0044] IV. Microstructure The microstructure of the gel was observed using a scanning electron microscope (S-4800Ⅱ, Hitachi, Japan). After gold sputtering, the lyophilized gel samples were observed at an accelerating voltage of 10 kV and a magnification of 500x.

[0045] The distribution of quinoa protein and β-glucan in the gel was observed using a confocal laser scanning microscope (LSM 880NLO, Zeiss, Germany). Gel sections were stained with rhodamine B (1.0 ml, 0.05% w / v) and fluorescent calcium white (1 ml, 0.1% w / v) for 1 min before observation.

[0046] The results are as follows Figure 3 As shown, SEM revealed the microstructure of the gel cross-section at 500x magnification. The addition of β-glucan resulted in the formation of a porous structure within the gel, while water channels decreased, indicating that β-glucan absorbed excess water from the surrounding proteins, promoting the formation of a three-dimensional gel network. In BG-4% and BG-5%, a finer porous structure and a reduction in larger voids were observed, which helps enhance the gel's resistance to external forces, resulting in stronger water retention and printability. CLSM revealed the distribution of proteins and β-glucan. With the addition of β-glucan, larger protein aggregates were observed, creating some voids. With increasing β-glucan content, aggregation of β-glucan was observed in BG-4% and BG-5%, filling the gaps in the protein network and forming a network structure. This indicates that β-glucan and quinoa protein formed an interpenetrating double-network gel.

[0047] V. Antioxidant properties Dissolve 0.5 g of lyophilized gel powder in 1 mL of 0.2 mM DPPH ethanol solution. Then incubate the mixture at 25°C in the dark for 30 min. Record the absorbance of the reaction solution at 517 nm using a spectrophotometer, with the DPPH ethanol solution as a blank control.

[0048] The results are as follows Figure 4 As shown, with the addition of β-glucan, the DPPH free radical scavenging ability of the β-glucan-quinoa protein interpenetrating double network gel is significantly improved, which is of great significance for functional foods.

[0049] VI. 3D Printing Performance 3D samples were fabricated using an injection-extrusion based 3D printer (FOODBOTS2-PRO, Hangzhou Shiyin Technology Co., Ltd.). Printing parameters were set as follows: nozzle temperature 25℃, nozzle diameter 1.2mm, layer height 0.8mm, print speed 15mm / s, linear infill pattern, and infill density 100%. A cube structure (15mm×15mm×15mm) was designed and printed to evaluate the 3D printing performance of the gel.

[0050] The results are as follows Figure 5As shown, adding 1-2% BG enhances the gel strength, but the support capacity for the cube remains insufficient to maintain its geometry. Adding 3% BG significantly improves the ink's printing performance, allowing for the observation of a complete cube shape, but the mechanical strength against gravity is insufficient. Using BG-4% and BG-5% as printing inks results in high printing accuracy, perpendicularity to the plane, smooth sample surfaces, and good self-support. The improved printing performance caused by β-glucan addition is related to the enhanced gel strength; simultaneously, β-glucan helps improve the gel's viscosity, enabling it to maintain its shape after printing.

[0051] VII. International Initiative for Standardization of Dietary Recommendations for Dysphagia (IDDSI) Based on the IDDSI framework, IDDSI tests were conducted, including fork dripping test, spoon tilt test, and fork pressure test.

[0052] The results are as follows Figure 6 As shown, when pressure is applied to the fork, all ink-printed cubes deform easily, the thumbnail applying pressure does not turn white, and the shape does not return to its original state after the pressure is removed. All gels can pass through the gaps between the forks, and clear fork indentations are visible, indicating that the samples have a safe particle size range. Therefore, all gels can be considered to belong to Level 4 (thick / very thick food) in the IDDSI framework. In the fork drip test, BG-0% ink has some fluidity, flowing down from the gaps at the fork tip, producing a short tail. This may be related to the gel network being damaged by external force during the test, causing gel flow and indicating that the QPI gel network itself is fragile. However, BG-0% did not drip extensively and can be classified as Level 4 (thick / very thick food) in the IDDSI framework. The gel ink with added β-glucan has increased strength, does not flow, and accumulates on the fork, also belonging to Level 4 (thick / very thick food) in the IDDSI framework. The adhesive ability of different gels was tested using a spoon tilting test. Foods with higher viscosity required more effort from the tongue to push the food bolus through the throat, thus increasing the risk of choking. Results showed that BG-0%, BG-1%, and BG-2% partially fell off after the spoon was tilted, with a significant amount remaining on the spoon. This indicates that BG-0%, BG-1%, and BG-2% are highly viscous and prone to adhesion during swallowing, therefore they do not belong to the IDDSI framework. BG-3%, BG-5%, and BG-5% mostly fell off after the spoon was tilted, with only a small portion remaining on the spoon; therefore, they can be classified as Level 4 (thick / very thick food) in the IDDSI framework. Overall, quinoa protein gel is not suitable as a food for dysphagia. The addition of β-glucan can improve its accessibility to the IDDSI framework, and within the 3-5% addition range, it belongs to Level 4 (thick / very thick food).

[0053] Although this application has been described in detail above with general descriptions, specific embodiments, and experiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of this application fall within the scope of protection claimed in this application.

Claims

1. A β-glucan-quinoa protein interpenetrating dual-network gel, characterized in that, Its raw materials include quinoa protein, β-glucan and water, and the concentration of quinoa protein in the gel is 5-25% and the concentration of β-glucan is 3-5%.

2. The β-glucan-quinoa protein interpenetrating double network gel according to claim 1, characterized in that, The β-glucan is oat β-glucan or barley β-glucan.

3. The method for preparing the β-glucan-quinoa protein interpenetrating double network gel according to claim 1 or 2, characterized in that, The quinoa protein, the β-glucan, and water were mixed evenly and then heated in a water bath to carry out a gelation reaction. After the reaction, the mixture was cooled and stored under cold storage to obtain a β-glucan-quinoa protein interpenetrating double network gel.

4. The preparation method according to claim 3, characterized in that, The water bath heating temperature is 60~90°C.

5. The preparation method according to claim 3, characterized in that, The cooling process includes ice bath cooling.

6. The preparation method according to claim 3, characterized in that, The refrigeration temperature should not exceed 4°C, and the time should be 12~24 hours.

7. The application of the β-glucan-quinoa protein interpenetrating double network gel according to claim 1 or 2 in the preparation of foods for dysphagia, characterized in that, The β-glucan-quinoa protein interpenetrating double network gel was 3D printed by extrusion to prepare dysphagia-related food.

8. The application according to claim 6, characterized in that, The amount of β-glucan added is 4-5%.

9. The application according to claim 6, characterized in that, The food causing the swallowing disorder is classified as level 4.

10. A food for dysphagia with IDSI level 4, characterized in that, It is prepared by 3D printing from the β-glucan-quinoa protein interpenetrating double network gel as described in claim 1 or 2.

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