A method for preparing a thermally reversible gel, its products and applications

Abstract

This invention relates to the field of food processing technology, providing a method for preparing a thermally reversible gel, its product, and its applications. The preparation method includes mixing a modified yeast protein solution and a gelatin solution; the gelatin has a Bloom value of 220-260. The thermally reversible gel provided by this invention exhibits good thermal stability and stable water-binding ability. It maintains its gel structure at near-oral temperatures and gradually softens and controllably disintegrates under the combined effects of body temperature and chewing shear, preventing solid-liquid separation during oral processing. Furthermore, its hardness, viscosity, and cohesion meet international dietary standards for dysphagia, achieving a balance between swallowing safety and eating comfort. This invention provides a safer and more comfortable food material for people with dysphagia, offers new material options for addressing the special dietary needs of people with dysphagia, expands the application pathways of yeast protein in high-value-added specialty foods, and promotes the high-value utilization of protein resources.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, and in particular to a method for preparing a thermally reversible gel, its product, and its application. Background Technology

[0002] Dysphagia is a common clinical symptom characterized by obstruction in the transfer of liquids or food from the mouth through the pharynx and esophagus to the stomach, increasing the risk of aspiration, choking, and aspiration pneumonia. This symptom has a high incidence in patients with stroke, neurodegenerative diseases, and those who have undergone head and neck tumor surgery. Furthermore, it is particularly prevalent in the elderly due to physiological decline. Dysphagia severely limits patients' effective food intake, and the resulting chronic protein deficiency is a key factor inducing weight loss, muscle atrophy, and even an increased risk of death. Therefore, developing nutritional supplements with appropriate textures is crucial for ensuring the quality of life for people with dysphagia.

[0003] Yeast protein (YP) is a food ingredient approved by the National Health Commission of my country. It is characterized by a high amino acid score and low allergenicity, effectively alleviating nutrient absorption disorders in the elderly caused by declining physiological function. However, industrially extracted yeast protein typically exhibits a tight, closed conformation and cannot independently form a gel under various processing conditions. Its weak gelling properties make it difficult to independently construct ideal food textures, limiting its application in the development of swallowing-friendly foods.

[0004] Gelatin (G), as a partial degradation product of collagen in animal connective tissue, has excellent gel properties and unique thermal reversibility. It can disintegrate from a stable gel network into a bolus structure with suitable fluidity at temperatures close to those in the human oral cavity. Under oral shear force and thermal induction, it can transform from a stable gel into a bolus structure with suitable fluidity, thereby optimizing the sensory experience while ensuring safe swallowing.

[0005] Currently, existing technologies mainly focus on yeast protein-polysaccharide systems or the combination of gelatin with other biopolymers. Research on using gelatin to improve the textural properties of yeast proteins is still lacking, and there are no reports on exploring the effect of gelatin Bloom value as a key regulatory parameter on the gelation properties of yeast proteins. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a method for preparing a thermally reversible gel, along with its product and applications.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This invention significantly improves the poor gelling properties of yeast proteins by introducing gelatin with different Bloom values. The two proteins induce rearrangement of the secondary structure of the gel through intermolecular interactions such as hydrogen bonds, increasing the proportion of ordered structures and promoting the formation of a structurally stable composite gel. This composite gel has typical thermally reversible gel properties.

[0008] In a first aspect, the present invention provides a method for preparing a thermally reversible gel, comprising: mixing a modified yeast protein solution and a gelatin solution; the solubility of the modified yeast protein is 48% to 53%; and the Bloom value of the gelatin is 220 to 260.

[0009] In this invention, the thermally reversible gel refers to a dual-protein gel, namely YP-G gel.

[0010] According to the method for preparing a thermally reversible gel provided by the present invention, preferably, the mass ratio of the modified yeast protein to the gelatin is (1-9):1.

[0011] More preferably, the mass ratio of the modified yeast protein to the gelatin is 1:1, 1.5:1, 7:3, 4:1 or 9:1.

[0012] More preferably, the mass ratio of the modified yeast protein to the gelatin is 1:1.

[0013] More preferably, the concentration of modified yeast protein in the modified yeast protein solution is 0.04 g / mL to 0.06 g / mL, and / or the concentration of gelatin in the gelatin solution is 0.04 g / mL to 0.06 g / mL.

[0014] More preferably, the concentration of modified yeast protein in the modified yeast protein solution is 0.04 g / mL, 0.045 g / mL, 0.05 g / mL, 0.055 g / mL, or 0.06 g / mL.

[0015] More preferably, the concentration of modified yeast protein in the modified yeast protein solution is 0.05 g / mL.

[0016] More preferably, the concentration of gelatin in the gelatin solution is 0.04 g / mL, 0.045 g / mL, 0.05 g / mL, 0.055 g / mL, or 0.06 g / mL.

[0017] More preferably, the concentration of gelatin in the gelatin solution is 0.05 g / mL.

[0018] According to a method for preparing a thermally reversible gel provided by the present invention, preferably, the method for preparing the modified yeast protein solution includes: dissolving the modified yeast protein in water at a mass concentration of 0.04 g / mL to 0.06 g / mL, and stirring at 42℃ to 48℃ for 1.5 h to 2.5 h.

[0019] More preferably, the modified yeast protein is dissolved in water at a mass concentration of 0.05 g / mL and stirred at 42℃~48℃ for 1.5 h~2.5 h.

[0020] More preferably, the modified yeast protein is dissolved in water at a mass concentration of 0.04 g / mL to 0.06 g / mL and stirred at 45°C for 1.5 h to 2.5 h.

[0021] More preferably, the modified yeast protein is dissolved in water at a mass concentration of 0.04 g / mL to 0.06 g / mL and stirred at 42°C to 48°C for 2 hours.

[0022] More preferably, the modified yeast protein is dissolved in water at a mass concentration of 0.05 g / mL and stirred at 45°C for 2 hours.

[0023] According to a method for preparing a thermally reversible gel provided by the present invention, preferably, the method for preparing the gelatin solution includes: dissolving the gelatin in water at a mass concentration of 0.04 g / mL to 0.06 g / mL, and stirring at 42℃ to 48℃ for 1.5 h to 2.5 h.

[0024] More preferably, the gelatin is dissolved in water at a mass concentration of 0.05 g / mL and stirred at 42℃~48℃ for 1.5 h~2.5 h.

[0025] More preferably, the gelatin is dissolved in water at a mass concentration of 0.04 g / mL to 0.06 g / mL and stirred at 45°C for 1.5 h to 2.5 h.

[0026] More preferably, the gelatin is dissolved in water at a mass concentration of 0.04 g / mL to 0.06 g / mL and stirred at 42°C to 48°C for 2 hours.

[0027] More preferably, the gelatin is dissolved in water at a mass concentration of 0.05 g / mL and stirred at 45°C for 2 hours.

[0028] According to the method for preparing a thermally reversible gel provided by the present invention, preferably, the solubility of the modified yeast protein is 48.5% to 52.5%.

[0029] More preferably, the solubility of the modified yeast protein is 48.58% to 52.32%.

[0030] According to the method for preparing a thermally reversible gel provided by the present invention, preferably, the modified yeast protein is obtained by modifying yeast protein with a pulsed electric field.

[0031] More preferably, the yeast protein has a protein content of ≥84%wt and a moisture content of ≤4%wt.

[0032] More preferably, the yeast protein has a protein content of ≥84.45%wt.

[0033] More preferably, the method of pulsed electric field modification includes: placing a yeast protein solution with a conductivity of 2.9 mS / cm to 3.1 mS / cm in a pulsed electric field for modification, wherein the conditions of the pulsed electric field include: an electric field strength of 18 kV / cm to 22 kV / cm.

[0034] More preferably, the conductivity of the yeast protein solution is 2.94 mS / cm to 3.02 mS / cm.

[0035] In some specific embodiments, the conductivity of the yeast protein solution is 2.94 mS / cm, 2.95 mS / cm, 2.96 mS / cm, 2.97 mS / cm, 2.98 mS / cm, 2.99 mS / cm, 3.00 mS / cm, 3.01 mS / cm or 3.02 mS / cm.

[0036] More preferably, the method for preparing the yeast protein solution includes: dissolving yeast protein in water at a mass concentration of 0.04 g / mL to 0.06 g / mL, stirring at 22℃ to 28℃ for 1.5 h to 2.5 h, and then fully hydrating at 3℃ to 5℃.

[0037] More preferably, the method for preparing the yeast protein solution includes: dissolving yeast protein in water at a mass concentration of 0.05 g / mL, stirring at 25°C for 2 h, and fully hydrating at 4°C.

[0038] More preferably, the conditions for the pulsed electric field further include: a pulse width of 8 μs to 12 μs, and / or an electric field frequency of 480 Hz to 520 Hz.

[0039] More preferably, the pulse width is 8 μs, 9 μs, 10 μs, 11 μs or 12 μs.

[0040] Most preferably, the pulse width is 10 μs.

[0041] More preferably, the electric field frequency is 480 Hz, 490 Hz, 500 Hz, 510 Hz or 520 Hz.

[0042] The most preferred electric field frequency is 500 Hz.

[0043] More preferably, the conditions for the pulsed electric field further include: an effective processing time of 0.6 ms to 1.0 ms, and / or an actual processing time of 7 min to 9 min.

[0044] In some specific implementations, the effective processing time is 0.6 ms, 0.7 ms, 0.8 ms, 0.9 ms, or 1.0 ms.

[0045] The optimal processing time is 0.8 ms.

[0046] In some specific implementations, the actual processing time is 7 min, 7.5 min, 8 min, 8.5 min, or 9 min.

[0047] The optimal processing time is 8 minutes.

[0048] More preferably, during the pulsed electric field modification process, the temperature of the yeast protein solution is controlled to be no higher than 30°C.

[0049] According to a method for preparing a thermally reversible gel provided by the present invention, preferably, a modified yeast protein solution and a gelatin solution are mixed at a temperature of 40°C to 50°C.

[0050] More preferably, the modified yeast protein solution and gelatin solution are mixed at a temperature of 42°C to 48°C.

[0051] More preferably, the modified yeast protein solution and gelatin solution are mixed at a temperature of 42°C, 43°C, 44°C, 45°C, 46°C, 47°C or 48°C.

[0052] More preferably, the modified yeast protein solution and gelatin solution are mixed at a temperature of 45°C.

[0053] More preferably, the modified yeast protein solution and gelatin solution are stirred at a temperature of 40℃~50℃ for 1.5 h~2.5 h.

[0054] More preferably, the modified yeast protein solution and gelatin solution are stirred at a temperature of 42℃~48℃ for 1.5h~2.5h.

[0055] More preferably, the modified yeast protein solution and gelatin solution are stirred at a temperature of 40℃~50℃ for 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2.0h, 2.1h, 2.2h, 2.3h, 2.4h or 2.5h.

[0056] More preferably, the modified yeast protein solution and gelatin solution are stirred at temperatures of 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, or 48°C for 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h, 2.1h, 2.2h, 2.3h, 2.4h, or 2.5h.

[0057] Most preferably, the modified yeast protein solution and gelatin solution are stirred at 45°C for 2 hours.

[0058] More preferably, the modified yeast protein solution and gelatin solution are mixed at a temperature of 40°C to 50°C, and then cooled and set.

[0059] More preferably, the temperature is cooled to ≤10°C. Under this temperature condition, the thermally reversible gel is in a stable solid state.

[0060] According to the method for preparing a thermally reversible gel provided by the present invention, preferably, the Bloom value of the gelatin is 230-250.

[0061] More preferably, the Bloom value of the gelatin is 230, 240, or 250.

[0062] More preferably, the gelatin has a Bloom value of 250.

[0063] According to the method for preparing a thermally reversible gel provided by the present invention, preferably, the weight-average molecular weight of the gelatin is 171 kg / mol to 220 kg / mol.

[0064] More preferably, the weight-average molecular weight of the gelatin is 189 kg / mol to 215 kg / mol.

[0065] More preferably, the weight-average molecular weight of the gelatin is 189 kg / mol, 201 kg / mol, or 215 kg / mol.

[0066] More preferably, the weight-average molecular weight of the gelatin is 215 kg / mol.

[0067] According to the method for preparing a thermally reversible gel provided by the present invention, preferably, the gelatin is alkali-processed gelatin.

[0068] According to the method for preparing a thermally reversible gel provided by the present invention, preferably, the gelatin is derived from pigs, cattle, sheep or fish.

[0069] More preferably, the gelatin is derived from bovine collagen.

[0070] According to the method for preparing a thermally reversible gel provided by the present invention, preferably, the gelatin is food-grade gelatin.

[0071] Secondly, the present invention also provides a thermally reversible gel, which is prepared by any of the methods described above for preparing a thermally reversible gel.

[0072] According to the present invention, a thermoreversible gel is preferably provided in a manner that corresponds to level 5 to 7 of the International Dietary Standards for Dysphagia.

[0073] More preferably, the thermoreversible gel corresponds to level 6 of the International Dietary Standards for Dysphagia.

[0074] Thirdly, the present invention also provides the application of the thermally reversible gel as a food, a food matrix, or a food additive.

[0075] The application of the thermoreversible gel provided by the present invention as a food, food matrix, or food additive is preferably suitable for people with swallowing disorders.

[0076] The present invention has the following beneficial effects: This invention provides a thermoreversible gel constructed from a blend of yeast protein and gelatin. This gel maintains its structure near oral temperature and then gradually softens and controllably disintegrates under the combined effects of body temperature and chewing shear, helping to prolong the appropriate texture maintenance time of the food bolus in the pharynx and reducing the risk of aspiration. This thermoreversible gel exhibits good thermal stability and stable water-binding capacity, preventing solid-liquid separation during oral processing. Furthermore, its hardness, viscosity, and cohesion meet international dietary standards for dysphagia. It maintains structural stability under low-shear conditions and rapidly reduces flow resistance under high-shear conditions, achieving a good balance between swallowing safety and eating comfort. This invention provides a safer and more comfortable food material for people with dysphagia, offers a new material option for addressing the special dietary needs of this population, expands the application pathway of yeast protein in high-value-added specialty foods, and promotes the high-value utilization of protein resources. Attached Figure Description

[0077] To more clearly illustrate the technical solutions in this invention 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 invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0078] Figure 1 These are morphological images of YP and various YP-G gels provided in Test Example 1 of this invention.

[0079] Figure 2The results are the particle size and zeta potential analysis results of YP and each YP-G gel provided in Test Example 2 of this invention; a is the particle size analysis result; b is the zeta potential analysis result; different lowercase letters indicate significant differences (p<0.05).

[0080] Figure 3 This is the circular dichroism spectrum of YP and each YP-G gel provided in Test Example 3 of the present invention.

[0081] Figure 4 This is the statistical result of the molecular weight percentage of the circular dichroism spectra of YP and each YP-G gel provided in Test Example 3 of the present invention.

[0082] Figure 5 The infrared spectra of YP and each YP-G gel provided in Test Example 3 of this invention are shown.

[0083] Figure 6 The fluorescence spectra of YP and each YP-G gel provided in Test Example 3 of this invention are shown.

[0084] Figure 7 The thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG) of YP provided in Test Example 4 of this invention are examples of the thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG).

[0085] Figure 8 The thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG) of YP-G220 provided in Test Example 4 of this invention are examples of the thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG).

[0086] Figure 9 The thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG) of YP-G230 provided in Test Example 4 of this invention are examples of the thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG).

[0087] Figure 10 The thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG) of YP-G240 provided in Test Example 4 of this invention are examples of the thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG).

[0088] Figure 11 The thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG) of YP-G250 provided in Test Example 4 of this invention are examples of the thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG).

[0089] Figure 12 The thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG) of YP-G260 provided in Test Example 4 of this invention are examples of the thermogravimetric curves (TGA) and derivative thermogravimetric curves (DTG).

[0090] Figure 13 The results are the strain scanning results of YP and each YP-G gel provided in Test Example 5 of this invention; a is the statistical result of storage modulus; b is the statistical result of loss modulus.

[0091] Figure 14The results are frequency scan results and dynamic temperature scan results of YP and each YP-G gel provided in Test Example 5 of this invention; a is the statistical result of storage modulus under frequency scan; b is the statistical result of loss modulus under frequency scan; c is the statistical result of loss tangent under frequency scan; d is the statistical result of storage modulus under dynamic temperature scan; e is the statistical result of loss modulus under dynamic temperature scan; f is the statistical result of melting temperature of each YP-G gel.

[0092] Figure 15 These are SEM images of the microstructures of YP and each YP-G gel provided in Test Example 6 of this invention. 100× and 500× are the magnifications of the corresponding fields of view.

[0093] Figure 16 The results are the water retention analysis results of YP and various YP-G gels provided in Test Example 7 of this invention; a is the statistical result of water retention; b is the statistical result of relaxation time; different lowercase letters indicate significant differences (p<0.05).

[0094] Figure 17 These are the textural properties analysis results of each YP-G gel provided in Test Example 8 of this invention; a is the statistical result of hardness; b is the statistical result of viscosity; c is the statistical result of cohesion; different lowercase letters indicate significant differences (p<0.05).

[0095] Figure 18 The results are the shear viscosity analysis results of YP and each YP-G gel provided in Test Example 9 of this invention.

[0096] Figure 19 The results are fork separation test results of YP-G220, YP-G230, YP-G240, YP-G250 and YP-G260 provided in Test Example 10 of the present invention.

[0097] Figure 20 These are the fork pressing test results of YP-G220, YP-G230, YP-G240, YP-G250 and YP-G260 provided in Test Example 10 of the present invention.

[0098] Figure 21 These are the spoon pressing test results of YP-G220, YP-G230, YP-G240, YP-G250 and YP-G260 provided in Test Example 10 of the present invention.

[0099] Figure 22 These are appearance diagrams of YP-G250 at different scales provided in Test Example 11 of the present invention.

[0100] Figure 23The results are the water-holding capacity analysis results of different proportions of YP-G250 provided in Test Example 11 of this invention; different lowercase letters indicate significant differences (p<0.05).

[0101] Figure 24 These are the gel strength analysis results of different proportions of YP-G250 provided in Test Example 11 of this invention; different lowercase letters indicate significant differences (p<0.05). Detailed Implementation

[0102] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0103] Unless otherwise specified, the experimental methods involved in the following embodiments are conventional methods in the art. For example, you can refer to the experimental manual in the art or follow the conditions recommended in the manufacturer's instructions.

[0104] Unless otherwise specified, all experimental materials and reagents used in the following examples are commercially available.

[0105] Example 1: Modification of yeast protein and evaluation of its processing functional properties 1. Methods for modifying yeast protein This embodiment uses a pulsed electric field (PEF) to modify yeast protein (protein ≥ 84.45% wt, moisture ≤ 4.00% wt) to improve its processing properties. The specific steps are as follows: (1) Preparation of yeast protein solution Yeast protein was dissolved in deionized water at a mass concentration of 5 g / 100 mL, stirred at 25°C for 2 h using a magnetic stirrer, and hydrated overnight at 4°C to obtain a yeast protein solution. Its conductivity was measured to be 2.98 ± 0.04 mS / cm.

[0106] (2) PEF treatment 1000 mL of yeast protein solution was subjected to PEF treatment. The pulse width was set to 10 μs, the electric field frequency to 500 Hz, the electric field strength to 20 kV / cm, the effective treatment time to 0.8 ms, and the actual treatment time to 8 min. During the PEF treatment, the temperature of the yeast protein solution was kept below 30℃ to avoid the influence of heat on the protein. After the PEF treatment, the yeast protein solution contained the modified yeast protein, denoted as YP.

[0107] (3) Freeze-drying The PEF-treated YP solution is subjected to vacuum freeze-drying, and the freeze-dried product is collected to obtain YP freeze-dried powder for subsequent use.

[0108] 2. Evaluation of YP's processing functional characteristics The solubility of unmodified yeast protein was 10.32%–12.39%, while the solubility of modified yeast protein was improved to 48.58%–52.32%, an increase of 3 to 4 times.

[0109] Example 2: A method for preparing a dual-protein (YP-G) gel In this embodiment, YP-G gel was prepared using gelatin with a Bloom value of 220 (G220, raw material source: bovine, weight-average molecular weight: 171 kg / mol, process type: alkaline method, grade: food grade). The specific steps are as follows: The YP lyophilized powder prepared in Example 1 was dissolved in deionized water at a mass concentration of 5 g / 100 mL, and stirred at 45°C for 2 h using a magnetic stirrer to obtain a YP solution.

[0110] G220 was dissolved in deionized water at a mass concentration of 5 g / 100 mL and stirred at 45 °C for 2 h using a magnetic stirrer to obtain a G220 solution.

[0111] The YP solution and G220 solution were mixed at a volume ratio of 1:1 and stirred at 45°C for 2 h to ensure thorough mixing, thus obtaining the YP-G gel, denoted as YP-G220.

[0112] After cooling the YP-G220 to room temperature, store it in a refrigerator at 4°C.

[0113] Example 3: A method for preparing a dual-protein (YP-G) gel In this embodiment, YP-G gel was prepared using gelatin with a Bloom value of 230 (G230, raw material source: bovine, weight-average molecular weight: 189 kg / mol, process type: alkaline method, grade: food grade). The specific steps are as follows: The YP lyophilized powder prepared in Example 1 was dissolved in deionized water at a mass concentration of 5 g / 100 mL, and stirred at 45°C for 2 h using a magnetic stirrer to obtain a YP solution.

[0114] G230 was dissolved in deionized water at a mass concentration of 5 g / 100 mL and stirred at 45 °C for 2 h using a magnetic stirrer to obtain a G230 solution.

[0115] The YP solution and G230 solution were mixed at a volume ratio of 1:1 and stirred at 45°C for 2 h to ensure thorough mixing, thus obtaining the YP-G gel, denoted as YP-G230.

[0116] After cooling the YP-G230 to room temperature, store it in a refrigerator at 4°C.

[0117] Example 4: A method for preparing a dual-protein (YP-G) gel In this embodiment, YP-G gel was prepared using gelatin with a Bloom value of 240 (G240, raw material source: bovine, weight-average molecular weight: 201 kg / mol, process type: alkaline method, grade: food grade). The specific steps are as follows: The YP lyophilized powder prepared in Example 1 was dissolved in deionized water at a mass concentration of 5 g / 100 mL, and stirred at 45°C for 2 h using a magnetic stirrer to obtain a YP solution.

[0118] G240 was dissolved in deionized water at a mass concentration of 5 g / 100 mL and stirred at 45 °C for 2 h using a magnetic stirrer to obtain a G240 solution.

[0119] The YP solution and G240 solution were mixed at a volume ratio of 1:1 and stirred at 45°C for 2 h to ensure thorough mixing, thus obtaining the YP-G gel, denoted as YP-G240.

[0120] After cooling the YP-G240 to room temperature, store it in a 4°C refrigerator.

[0121] Example 5: A method for preparing a dual-protein (YP-G) gel In this embodiment, YP-G gel was prepared using gelatin with a Bloom value of 250 (G250, raw material source: bovine, weight-average molecular weight: 215 kg / mol, process type: alkaline method, grade: food grade). The specific steps are as follows: The YP lyophilized powder prepared in Example 1 was dissolved in deionized water at a mass concentration of 5 g / 100 mL, and stirred at 45°C for 2 h using a magnetic stirrer to obtain a YP solution.

[0122] G250 was dissolved in deionized water at a mass concentration of 5 g / 100 mL and stirred at 45 °C for 2 h using a magnetic stirrer to obtain a G250 solution.

[0123] The YP solution and G250 solution were mixed at a volume ratio of 1:1 and stirred at 45°C for 2 h to ensure thorough mixing, thus obtaining the YP-G gel, denoted as YP-G250.

[0124] After cooling the YP-G250 to room temperature, store it in a refrigerator at 4°C.

[0125] Example 6: A method for preparing a dual-protein (YP-G) gel In this embodiment, YP-G gel was prepared using gelatin with a Bloom value of 260 (G260, raw material source: bovine, weight average molecular weight: 220 kg / mol, process type: alkaline method, grade: food grade). The specific steps are as follows: The YP lyophilized powder prepared in Example 1 was dissolved in deionized water at a mass concentration of 5 g / 100 mL, and stirred at 45°C for 2 h using a magnetic stirrer to obtain a YP solution.

[0126] G260 was dissolved in deionized water at a mass concentration of 5 g / 100 mL and stirred at 45 °C for 2 h using a magnetic stirrer to obtain a G260 solution.

[0127] The YP solution and G260 solution were mixed at a volume ratio of 1:1 and stirred at 45°C for 2 h to ensure thorough mixing, thus obtaining the YP-G gel, denoted as YP-G260.

[0128] After cooling the YP-G260 to room temperature, store it in a refrigerator at 4°C.

[0129] Macroscopic morphology observation of YP-G gel in Test Example 1 1. Testing Method The PEF-treated YP solution prepared in Example 1 and the YP-G220 to YP-G260 prepared in Examples 2 to 6 were placed in sample bottles and petri dishes of the same volume for macroscopic morphology observation and gelation characteristics characterization.

[0130] 2. Test Results like Figure 1 As shown, at 4℃, the single-component YP solution exhibits a typical flow state and cannot form a stable gel; however, YP-G220 to YP-G260 with the introduction of gelatin of different Bloom values ​​can all form hydrogels, indicating that gelatin is beneficial to the physical cross-linking and three-dimensional network formation in the composite system.

[0131] Furthermore, YP-G gels constructed from gelatin with different Bloom values ​​exhibited significant differences in macroscopic morphology. When the Bloom value was 220, the structure of YP-G220 was loose and prone to collapse. As the Bloom value of gelatin increased to 250, the appearance of YP-G230, YP-G240, and YP-G250 tended to be smooth and stable, and the macroscopic gelation state was significantly improved. However, when the Bloom value was further increased to 260, the surface of YP-G260 again showed depressions and collapse, which may be related to the uneven shrinkage of the system structure under excessively high Bloom values.

[0132] The above results indicate that gelatin can effectively improve the gelling properties of YP, but its Bloom value needs to be controlled within a reasonable range. Too low or too high values ​​are not conducive to the formation of a structurally stable dual-protein composite gel system.

[0133] Test Example 2: Determination of Particle Size and Potential of YP-G Gel 1. Testing Method The YP-G220 to YP-G260 prepared in Examples 2 to 6 were subjected to vacuum freeze drying to obtain the freeze-dried products of YP-G220 to YP-G260.

[0134] The YP lyophilized powder and the lyophilized products of YP-G220 to YP-G260 prepared in Example 1 were dissolved in deionized water at a concentration of 0.5 mg / mL, and the particle size and zeta potential were measured using a particle size analyzer.

[0135] 2. Test Results (1) Particle size measurement results The aggregation behavior of proteins in a gel system can be visually reflected by changes in particle size.

[0136] like Figure 2 As shown in Figure a, compared with the single-component YP system, the average particle size of the composite gel system increased overall after the introduction of gelatin, and the particle size change was significantly affected by the Bloom value of gelatin. When the Bloom value increased from 220 to 250, the particle size of YP-G220 to YP-G250 gradually increased, reaching a maximum value (335.2 nm) at YP-G250, indicating that gelatin with moderate gel strength can induce ordered assembly of YP particles. However, when the Bloom value further increased to 260, the particle size of YP-G260 decreased significantly but was still significantly higher than that of YP-G220. In the process of constructing a gel with yeast protein, there is an optimal threshold for the gel strength of gelatin. This may be because gelatin with a higher Bloom value has a longer molecular chain, which increases the steric hindrance during the gelation process of gelatin, which is not conducive to the formation of composite gel.

[0137] (2) Results of Zeta potential measurement Zeta potential can reflect the surface charge characteristics of proteins and their related behaviors; its absolute value often reflects the stability of the system.

[0138] like Figure 2 As shown in b, all six systems are negatively charged. Compared with the single-component YP system, the absolute values ​​of the Zeta potential of YP-G220 to YP-G260 show a trend of first increasing and then decreasing with the increase of Bloom value, which is basically consistent with the particle size variation. Among them, YP-G250 exhibits the highest absolute value of Zeta potential (20.12 mV), indicating that it has the best gel stability.

[0139] The results indicate that the Bloom value of gelatin significantly affects the structural stability of YP-G gels by regulating the aggregation state and charge distribution of proteins. Gelatin with a Bloom value of 250 (G250) is more effective in promoting orderly particle aggregation and maintaining charge stability.

[0140] Structural characterization of YP-G gel in Test Example 3 1. Testing Method (1) Circular dichroism (CD) spectrum The YP-G220 to YP-G260 prepared in Examples 2 to 6 were subjected to vacuum freeze drying to obtain the freeze-dried products of YP-G220 to YP-G260.

[0141] The YP lyophilized powder and the lyophilized products of YP-G220 to YP-G260 prepared in Example 1 were dissolved in deionized water at a concentration of 0.5 mg / mL. Secondary structure analysis was performed using a circular dichroism spectroscopy polarimeter with the following measurement parameters: wavelength range of 190–260 nm, bandwidth of 1 nm, and scan rate of 50 nm / min. Deionized water was used as the background. The secondary structure content of each gel sample was calculated using CDNN software.

[0142] (2) FTIR (Frequency and Infrared Spectroscopy) Potassium bromide was used as the background. The YP lyophilized powder prepared in Example 1 and the lyophilized products of YP-G220 to YP-G260 were ground into powder with potassium bromide (mass ratio 1:100) in an agate mortar. The powders were then pressed into 1 mm sheets and analyzed using a Fourier transform infrared spectroscopy spectrometer at 4000–450 cm⁻¹. -1 Within the wavenumber range of 4 cm -1 The system was scanned at a resolution of 32 times.

[0143] (3) Fluorescence spectrum The YP lyophilized powder and the lyophilized products of YP-G220 to YP-G260 prepared in Example 1 were dissolved in deionized water at a concentration of 0.5 mg / mL. The emission spectra were recorded using a fluorescence spectrophotometer with the following parameters: the excitation wavelength was adjusted to 280 nm, the slit width was 5 nm, and the scanning speed was 1200 nm / min. The emission spectra in the wavelength range of 300 to 450 nm were recorded to analyze the tertiary structure of the gel.

[0144] 2. Test Results (1) Circular dichroism spectral results The local folding and arrangement patterns of protein secondary structure are key factors that determine the functional properties of gels.

[0145] like Figure 3 As shown, YP exhibits a positive absorption band at approximately 195 nm and a negative absorption band in the 207–215 nm region, consistent with typical β-sheet structure characteristics. After introducing gelatin with different Bloom values, YP-G220–YP-G260 show negative peaks at 205–210 nm and 220–225 nm, indicating that the introduction of gelatin with different Bloom values ​​promotes the transformation of the β-sheet structure in the secondary structure of YP towards α-helices and β-turns.

[0146] To further clarify the influence of gelatin with different Bloom values ​​on the changes in the secondary structure of YP, quantitative analysis was performed on the CD spectrum.

[0147] like Figure 4 As shown, after adding gelatin with different Bloom values, the β-fold proportion of YP decreased from 41% to 30%, the α-helix proportion increased from 8% to 13%, and the β-turn proportion increased from 19% to 26%.

[0148] Generally, an increase in α-helix content signifies an increase in the density of hydrogen bonds within protein aggregates, which is beneficial for forming more rigid and compact complexes. An increase in β-turns promotes moderate stretching of peptide chains, thereby fostering the formation of a more uniform three-dimensional network structure and enhancing the gel's water retention capacity and mechanical strength. β-sheets form rigid sheet-like structures through interchain hydrogen bonding; a decrease in β-sheet content indicates a reduction in the rigid sheet stacking between protein molecules, making the gel network more flexible and contributing to improved fracture resistance.

[0149] The above results indicate that gelatin with different Bloom values ​​induces rearrangement of the secondary structure of the gel by forming hydrogen bonds with YP, thereby increasing the proportion of ordered structures such as α-helices and β-turns.

[0150] (2) Infrared spectral results To further elucidate the molecular mechanism by which gelatin induces the adjustment of the secondary structure of YP, FTIR was used to analyze the functional groups and intermolecular interactions in the YP-G system.

[0151] like Figure 5 As shown, compared with the single-component YP system, YP-G220~YP-G260 exhibit better performance in the amide A band (3800~3000cm). -1 The characteristic absorption peak of the sample shows a red shift, and this absorption band is usually associated with the stretching vibration of OH groups bonded by hydrogen bonds, indicating that the hydrogen bond interactions in the system are enhanced after the addition of gelatin with different Bloom values. Meanwhile, at 2923 cm⁻¹... -1The corresponding CH stretching vibration peak at this point shows a blue shift, indicating the presence of hydrophobic interactions in the YP-gelatin composite system.

[0152] In addition, Fourier transform infrared spectroscopy revealed a characteristic protein region: the amide I band (1700–1600 cm⁻¹). -1 This corresponds to the C=O stretching vibration and the NH bending vibration. Amide II band (1600–1500 cm⁻¹) -1 It originates from the stretching vibration of CN and the bending vibration of NH. Amide III band (1500–1200 cm) -1 The variation is attributed to a combination of NH bending vibrations and CN stretching vibrations. Compared to YP, the infrared spectra of different Bloom values ​​show a slight blue shift in these characteristic absorption peaks, indicating a complex hydrogen bonding interaction between YP and gelatin, which induces conformational changes in the protein structure. The changes in the amplitude of the infrared absorption bands and the slight shift in peak position indicate that the intermolecular interaction between gelatin and YP facilitates the internal binding of the composite gel, thereby promoting the evolution of the system into a more stable and ordered gel network.

[0153] (3) Fluorescence spectroscopy results The effects of gelatin with different Bloom values ​​on the conformational characteristics of YP-G gel were further investigated by analyzing the exposure level of aromatic amino acids using fluorescence spectroscopy.

[0154] like Figure 6 As shown, the maximum emission wavelength of all samples was located at 345 nm, with no significant shift between different samples, but the fluorescence intensity varied significantly. The single-component YP exhibited the highest fluorescence intensity, while the fluorescence intensities of YP-G220 to YP-G260 all decreased significantly, exhibiting typical fluorescence quenching. This indicates that the microenvironment of tryptophan residues in gelatin YP with different Bloom values ​​was altered. This phenomenon may be due to gelatin enhancing the intermolecular interaction between gelatin and YP. On one hand, gelatin forms a supramolecular structure with YP through physical cross-linking interactions such as hydrogen bonding, partially encapsulating or shielding the tryptophan residues in YP, leading to fluorescence quenching. On the other hand, this interaction may induce a conformational change in YP, exposing the internal tryptophan residues from their original hydrophobic core to a more polar environment.

[0155] Test Example 4: Thermal Stability Analysis of YP-G Gel 1. Testing Method The YP-G220 to YP-G260 prepared in Examples 2 to 6 were subjected to vacuum freeze drying to obtain the freeze-dried products of YP-G220 to YP-G260.

[0156] Two mg of the YP lyophilized powder prepared in Example 1 and the lyophilized products of YP-G220 to YP-G260 were weighed and heated from 40°C to 550°C at a heating rate of 15°C / min under nitrogen atmosphere. Since the thermal stability of proteins is closely related to their spatial conformational order and intermolecular interactions, thermogravimetric analysis (TGA) and derivative thermogravimetric analysis (DTG) were used to assess thermal stability. An empty crucible was used as a control in the experiment.

[0157] 2. Test Results like Figures 7-12 As shown, the two main weight losses observed in all samples during thermal decomposition can be roughly divided into two stages: the slight weight loss initially observed in the first stage (40℃~150℃) is attributed to the evaporation of water in the gel network; the significant weight loss observed in the second stage (200℃~400℃) corresponds to the thermal degradation of peptide chains and the breaking of non-covalent bonds. According to the DTG curves, the maximum degradation temperature of YP is 318℃, the maximum degradation temperature of YP-G220, YP-G230, YP-G240 and YP-G260 is 323℃, and the maximum degradation temperature of YP-G250 is 326℃.

[0158] The results indicate that introducing gelatin with different Bloom values ​​delayed the thermal degradation process of YP-G gels, thereby improving their thermal stability to some extent. This improvement may be due to the fact that the introduction of gelatin led to the formation of a stable three-dimensional gel network structure in the composite system, allowing YP to be uniformly embedded and integrated into the network, thus enhancing the heat resistance of the composite system.

[0159] Rheological property analysis of YP-G gel in Test Example 5 1. Testing Method Before the measurement, strain scanning was performed on the PEF-treated YP solution prepared in Example 1 and the YP-G220 to YP-G260 prepared in Examples 2 to 6. The scanning conditions were set as follows: frequency of 1 Hz, 0.01% to 100%, to determine the linear viscoelastic region (LVR) of the gel.

[0160] Each sample was placed on a parallel plate of a 50 mm rheometer with a slit width of 1 mm. Frequency scanning and dynamic temperature scanning were performed within the LVR.

[0161] The frequency scanning conditions were set as follows: frequency 0.1–10 Hz, strain 1%, temperature 4℃. The values ​​of G' and G'' for each gel sample as a function of frequency were recorded.

[0162] The dynamic temperature scanning conditions were set as follows: frequency 1 Hz, strain 1%, and heating and cooling rates of 5℃ / min. The sample was heated from 4℃ to 50℃, held at 50℃ for 3 min, and then cooled from 50℃ to 4℃. The storage modulus (G') and loss modulus (G'') of the sample as a function of temperature were recorded.

[0163] 2. Test Results Strain scanning is often used to evaluate gel properties and structural changes under nonlinear conditions.

[0164] like Figure 13 As shown in figures a and b, the changes in G' and G'' of YP and YP-G gels under different strain conditions are observed. Within the strain range of 0.01% to 10%, G' and G'' of YP-G220 to YP-G260 remain constant, indicating the presence of LVR in the YP-G gel. Furthermore, within the LVR, G' is significantly higher than G'', while the modulus change is not significant, reflecting a stable three-dimensional network structure. When the strain further increases to above 10%, G' of the YP-G gel begins to decrease significantly, indicating that the gel's network structure gradually deteriorates under higher strain conditions.

[0165] To further analyze the flow and structural properties of the gels, frequency scanning was performed on YP and YP-G gels within an LVR (strain of 1%).

[0166] like Figure 14 As shown in a and b, within the test frequency range, the G' of YP-G220 to YP-G260 is greater than its G'', exhibiting typical network-like solid gel structure characteristics. At the same time, compared with the single-component YP system in solution (G', G''≈0), the G' of the five YP-G gels is significantly increased, indicating that the introduction of gelatin with different Bloom values ​​can promote the rapid formation of cross-linked regions and enhance the gel network.

[0167] The relative importance of the viscous and elastic behaviors of the samples was assessed using the loss tangent (tanδ).

[0168] like Figure 14 As shown in c, the tanδ values ​​of the five YP-G gels are all between 0.005 and 0.20 (tanδ < 1), and do not change significantly with frequency, indicating that a highly stable and resilient network structure has formed inside the YP-G gel. This rheological property, which combines stability and moderate elasticity, provides a physical basis for a good taste experience.

[0169] To investigate the gelation properties of YP and YP-G gels under varying temperature conditions, dynamic temperature scanning was performed on the samples within an LVR (strain of 1%).

[0170] like Figure 14As shown in d and e, the G' and G'' values ​​of the five YP-G gels were significantly higher than those of the single-component YP system (G', G''≈0), further confirming that the introduction of gelatin with different Bloom values ​​provided key physical cross-linking sites, effectively compensating for the insufficient independent gelling ability of YP. Meanwhile, with the increase of the gelatin Bloom value, the G' and G'' values ​​of the YP-G gels generally showed a trend of first increasing and then decreasing, reaching their maximum at a Bloom value of 250, indicating that its gel network structure was more compact and stable. This may be because, compared with gelatin with a Bloom value of 250, gelatin with lower gel strength (220–240) has shorter peptide chains and weaker triple helix nucleation ability, thus limiting the effective construction of the gel network; while excessively high Bloom values ​​(260) may weaken the synergistic interaction between yeast proteins and gelatin molecules, hindering the orderly aggregation and conformational rearrangement of molecules, and weakening the cross-linking density.

[0171] Further analysis of the temperature scanning results revealed that the YP-G gels exhibited typical thermally reversible gel properties. With increasing temperature, the G' and G'' values ​​of all five YP-G gels decreased significantly, exhibiting cross-pollination during heating, indicating that the gel network gradually disintegrated under thermal action, transitioning from a gel state to a sol state. During subsequent cooling, G' and G'' increased again, and the gel network was reconstructed, confirming the system's excellent thermal reversibility.

[0172] The melting temperatures of five YP-G gels were statistically analyzed, and the results are as follows: Figure 14 As shown in f, with the increase of the gelatin Bloom value, the melting temperature of YP-G gel during the transition from gel to sol state first increases and then decreases, all remaining above 20℃, with YP-G250 exhibiting the highest melting temperature (approximately 32.4℃). This characteristic allows it to maintain its gel structure to some extent even in environments close to oral temperature (approximately 37℃). Subsequently, under the combined action of body temperature and chewing shear, it gradually softens and undergoes controlled structural disintegration, thereby helping to prolong the appropriate texture maintenance time of the food bolus in the oral cavity and pharynx, reducing the risk of aspiration, and providing a safer and more comfortable eating experience for people with dysphagia.

[0173] Test Example 6: Microstructure Characterization of YP-G Gel 1. Testing Method To gain a deeper understanding of the microstructural basis for the improved mechanical strength and thermal stability of the YP-G system, the YP lyophilized powder prepared in Example 1 and the lyophilized products of YP-G220 to YP-G260 prepared in Examples 2 to 6 were fixed on SEM columns with double-sided tape and observed by magnification at 100x and 500x under an accelerating voltage of 10 kV.

[0174] 2. Test Results like Figure 15 As shown, single-component YP exhibits irregular spherical particles accompanied by numerous irregular blocky aggregates. After the introduction of gelatin, the microstructure of the YP-G gel composite system changes significantly, forming an interconnected multilayered porous sheet-like structure. YP particles are uniformly fixed on the inner walls of the gel sheet-like structure, indicating that gelatin participates in constructing a continuous phase system during gel formation, effectively connecting and stabilizing the originally dispersed yeast protein particles. As the Bloom value of gelatin increases from 220 to 250, the pore size of YP-G220–YP-G260 decreases significantly, the sheet-like structure becomes denser, and the network distribution becomes more uniform. Among them, YP-G250 exhibits the finest and most stable network distribution, indicating that gelatin at this strength can better bind with YP particles, enhancing structural integrity. However, when the Bloom value of gelatin increases to 260, the gel network structure becomes loose and uneven, indicating that excessively high gel strength is also detrimental to the formation of a continuous network in the YP-G gel system.

[0175] In summary, the dense and uniform microstructure of YP-G250 is consistent with its superior characteristics in various characterizations such as particle size distribution, zeta potential, thermal stability and rheology, which morphologically confirms that the system has formed the most stable and continuous three-dimensional gel skeleton.

[0176] Test Example 7: Characterization of the water retention properties of YP-G gel 1. Testing Method (1) Water holding capacity test Water-holding capacity is a key indicator for measuring the stability and water-binding ability of protein gels. For the PEF-treated YP solution prepared in Example 1 and the YP-G220 to YP-G260 prepared in Examples 2 to 6, appropriate amounts of samples were placed in 50 mL centrifuge tubes. The mass of the centrifuge tubes was recorded as m1, and the total mass of the samples and centrifuge tubes was recorded as m2.

[0177] Centrifuge at 6000 rpm for 10 min, remove the supernatant, and blot the surface moisture of the sample with filter paper. Weigh the sample and the total mass of the centrifuge tube, and record it as m3. Calculate the water-holding capacity using the formula: Water-holding capacity = (m2-m3) / (m2-m1) × 100%.

[0178] (2) Moisture distribution measurement To reveal the distribution of water in the YP-G gel system and its interaction with the gel network, low-field nuclear magnetic resonance (NMR) was used to analyze the transverse relaxation time of water in the sample.

[0179] For the PEF-treated YP solution prepared in Example 1 and the YP-G220 to YP-G260 prepared in Examples 2 to 6, 1g of sample was placed in a nuclear magnetic resonance (NMR) spectroscopy tube, and the transverse relaxation time (T2) was measured using a CPMG pulse sequence to analyze the variation of water distribution in the sample.

[0180] 2. Test Results like Figure 16 As shown in Figure a, the water-holding capacity of single-component YP is relatively poor. After adding gelatin, the water-holding capacity of YP-G gels is significantly improved, with YP-G220 to YP-G260 all reaching over 99%. This indicates that the three-dimensional network structure constructed by gelatin possesses stable water-binding ability, which is beneficial for the uniform distribution of water in the gel matrix. Although gelatin with different Bloom values ​​has a certain regulatory effect on the density of the three-dimensional network, the water-holding capacity of YP-G220 to YP-G260 did not show significant differences. This may be related to the fact that under the current formulation conditions, the continuous physical network formed by gelatin already possesses sufficient water-binding capacity.

[0181] like Figure 16 As shown in b, YP and YP-G220 to YP-G260 all exhibit three characteristic peaks, corresponding to strongly bound water (T) tightly bound to macromolecules. 21 : 0~10 ms), and weakly bound water that is loosely bonded to the surface (T 22 (10–100 ms) and free water (T) embedded in the gel network 23 (100–10000 ms). Compared to single-component YP, the Tg of YP-G gel increased after the addition of gelatin. 21 T 22 T 23 All showed a leftward shift, indicating that the movement of water molecules was restricted, the interaction between water and the gel network was significantly enhanced, and free water was more effectively bound within the three-dimensional network structure. Meanwhile, in all YP-G gels, free water (T... 23 The peak area ratio is the highest and the signal amplitude is the strongest, indicating that free water is the main form present in YP-G gel.

[0182] Further comparison revealed that the T values ​​of YP-G220 to YP-G260... 21 T 22 and T 23 The relaxation time did not differ significantly with the Bloom value of gelatin, indicating that the introduction of gelatin is the dominant factor in enhancing the water binding capacity, while the effect of different Bloom values ​​on the water state distribution is relatively limited.

[0183] The above results indicate that YP-G gel has a stable water-binding capacity, which helps to prevent solid-liquid separation during oral processing and reduces the potential risk of aspiration during swallowing.

[0184] Test Example 8: Texture Analysis of YP-G Gel 1. Testing Method Texture properties are the core indicators for evaluating the sensory quality and swallowability of gel-based foods.

[0185] This test case references Japan's definition of "easily swallowable foods" (hardness below 15000 N / m). 2 Viscosity less than 1000 J / m 2 The effects of gelatin with different Bloom values ​​on the gel texture parameters of YP-G were investigated (with cohesiveness ranging from 0.2 to 0.9).

[0186] The parameters were set as follows: pre-test rate 0.5 mm / s, test rate 1.5 mm / s, post-test rate 2.0 mm / s, trigger force 0.15 N, and deformation 20%. The hardness, viscosity, and cohesiveness of YP-G220 to YP-G260 prepared in Examples 2 to 6 were measured. Each sample was measured 6 times and the average value was taken.

[0187] 2. Test Results like Figure 17 As shown in a to c, the hardness, viscosity, and cohesiveness of YP-G220 to YP-G260 all meet the requirements of this standard, indicating that the introduction of gelatin can significantly improve the textural properties of the YP system, making it more suitable for the dietary needs of people with dysphagia. Among them, the hardness of YP-G250 is approximately 2733 N / m (2.27 ± 0.10 N). 2 )), viscosity (3.70 ± 0.98 mJ (≈ 7.54 J / m) 2 The YP-G250 has the best cohesion (0.78 ± 0.18), which means that the food bolus can remain firm and not easily fall apart when squeezed by the tongue and palate. It has stronger resistance to deformation and can provide a safer and more comfortable eating experience for people with swallowing disorders.

[0188] Test Example 9: Shear viscosity of YP-G gel 1. Testing Method Shear viscosity reflects the structural response of food to shear stimuli during oral processing and swallowing, and is a key indicator for evaluating the rheological adaptability of dysphagia-friendly foods.

[0189] Within the LVR measured in Test Example 5, the gel shear viscosity of the PEF-treated YP solution prepared in Example 1 and the YP-G220 to YP-G260 prepared in Examples 2 to 6 was tested.

[0190] Each sample was placed on a parallel plate of a 50 mm rotational rheometer with a slit width of 1 mm. The time intervals were 0.1–100 s. -1 Steady-state scanning tests were performed at shear rates, and the shear viscosity of each sample was recorded.

[0191] 2. Test Results like Figure 18 As shown, the shear viscosity of the single-component YP system changes little with the shear rate and remains at a low level, indicating that it lacks stable structural support and is difficult to form a suitable swallowing texture. After adding gelatin, the shear viscosity of YP-G220 to YP-G260 decreases with the increase of shear rate, all exhibiting typical pseudoplastic non-Newtonian fluid characteristics, confirming that it has typical shear thinning properties.

[0192] Under low shear rate conditions (1 s -1 The shear viscosity of YP-G220 to YP-G260 showed a trend of first increasing and then decreasing with the increase of Bloom value. Among them, YP-G250 showed the highest shear viscosity, indicating that it can maintain a relatively stable gel structure under weak shear conditions, which is conducive to the food bolus maintaining its integrity in the initial stage of oral cavity, thereby compensating for the risk of leakage and aspiration caused by delayed epiglottic closure in the elderly.

[0193] As the shear rate increased to 50 s in simulated oral cavity processing -1 At that time, the viscosity of YP-G220~YP-G260 was related to the viscosity at 1 s. -1 The shear rates of all components were reduced compared to those of YP-G230 and YP-G260. Among them, YP-G250 exhibited more significant shear sensitivity, with its apparent viscosity rapidly decreasing to a level similar to other components (such as YP-G230 and YP-G260) under high shear. This efficient shear response not only reduces physical resistance during transport, facilitating the smooth passage of food boluses through the throat, but also reduces the stickiness during ingestion, enhancing the smoothness of the texture.

[0194] The above results indicate that the rheological characteristics of YP-G gel, which maintain structural stability under low shear conditions and rapidly reduce flow resistance under high shear conditions, achieve a good balance between swallowing safety and eating comfort, helping to reduce stickiness during oral processing and improve the overall swallowing experience.

[0195] Test Example 10: IDDSI Test of YP-G Gel 1. Testing Method To visually assess the applicability of YP-G gel in dysphagia diets, this test case uses the International Dysphagia Diet Standardisation Initiative (IDDSI) to evaluate the swallowing performance of YP-G220 to YP-G260 prepared in Examples 2 to 6.

[0196] To determine whether the gels met the IDDSI Level 6 criteria (i.e., soft texture and easy chewing), YP-G220 to YP-G260 were cut into 1.5cm × 1.5cm × 1.2cm cubes. Fork separation test, fork pressing test, and spoon pressing test were then performed. The structural response and separation behavior of each YP-G gel under stress conditions were observed according to the research methods in IDDSI.

[0197] 2. Test Results like Figures 19-21 As shown, YP-G220 and YP-G260 can be easily cut. When pressed with a fork or spoon, water separation easily occurs on the surface, and the internal structure is uneven. Small block structures can be observed to separate under pressure, indicating that they cannot maintain a continuous and stable bolus shape under simulated swallowing conditions and fail to exhibit ideal structural integrity, consistent with the weak network support capacity shown in the aforementioned texture and rheological analyses. YP-G230, YP-G240, and YP-G250 showed more consistent performance in the IDDSI test. When pressure equivalent to that applied by the tongue to crush food (approximately 17 kPa) is applied, all three YP-G gels can be easily crushed by a fork and spoon and undergo irreversible deformation. They can be easily separated under pressure and do not elastically retract, and can be classified as IDDSI Grade 6 (soft and palatable) food, suitable for feeding scenarios of patients with swallowing disorders.

[0198] Further analysis of YP-G250, which meets the IDSI Level 6 standard, was conducted, combining the aforementioned microstructure, textural properties, and rheological behavior. The results showed that YP-G250 possesses the densest and most uniform network structure. This compact microskeleton provides effective spatial confinement for water, ensuring the stability of the food bolus during oral processing. Correspondingly, its high cohesion and hardness, as observed in the textural analysis, indicate that the gel can maintain good bolus integrity without excessive fragmentation under tongue compression and mild chewing conditions. Rheological results further demonstrate that the thermally reversible YP-G250 exhibits good structural support under low shear conditions, while showing significant shear thinning behavior under high shear conditions, effectively adapting to the changes in the mechanical environment from static to dynamic during swallowing. In conclusion, YP-G250 achieves a high degree of synergy between its micronetwork, mechanical cohesion, and rheological response, demonstrating greater potential as a swallowing-friendly food while strictly adhering to the IDSI Level 6 standard.

[0199] Test Example 11: Effect of Changes in the Amounts of Yeast Protein and Gelatin on YP-G250 1. Testing Method (1) Preparation of YP-G250 with different proportions This test set up six different ratios of yeast protein to G250 gelatin, which, by mass ratio, were 10:0, 9:1, 8:2, 7:3, 6:4 and 5:5 (i.e., 1:1).

[0200] Based on the above proportions, the method of Example 5 was followed, except that the YP solution and G250 solution were mixed in volume ratios of 10:0, 9:1, 8:2, 7:3, 6:4, and 5:5. The resulting products were subsequently designated as YP-G-10 / 0, YP-G-9 / 1, YP-G-8 / 2, YP-G-7 / 3, YP-G-6 / 4, and YP-G-5 / 5.

[0201] (2) Macroscopic morphological observation Follow the method described in Test Example 1.

[0202] (3) Water holding capacity test Follow the method described in Test Example 7.

[0203] (4) Gel strength determination The test parameters were set as follows: pre-test speed 0.5 mm / s, test speed 1.5 mm / s, post-test speed 2.0 mm / s, and trigger force 15 g. The force required under these conditions is expressed as gel strength (g). The gel strength of YP-G250 gels with different volume ratios was measured. Each sample was measured 6 times and the average value was taken.

[0204] 2. Test Results like Figure 22 As shown, at 4℃, YP-G-10 / 0 could not form a stable gel because only the YP solution exhibited a typical flow state. However, after introducing gelatin, YP-G-9 / 1, YP-G-8 / 2, YP-G-7 / 3, YP-G-6 / 4, and YP-G-5 / 5 all formed hydrogels, indicating that gelatin helps promote physical cross-linking and the formation of a three-dimensional network structure in the composite system. Furthermore, the YP-G250 gels constructed with different gelatin ratios showed no significant differences in macroscopic morphology.

[0205] like Figure 23 As shown, the strength properties of YP-G250 gels are highly dependent on the amount of gelatin added. With a stepwise increase in the amount of gelatin added, the strength of YP-G-9 / 1, YP-G-8 / 2, YP-G-7 / 3, YP-G-6 / 4, and YP-G-5 / 5 gradually increases, confirming the positive role of gelatin as a structural reinforcing component in the gel formation process. Particularly in the YP-G-5 / 5 sample, its gel strength was significantly higher than the other control groups, reaching the highest level in the entire experimental series. This indicates that the formulation ratio of YP-G-5 / 5 may have precisely achieved the optimal balance point for the interaction between gelatin and the YP-G250 backbone, thus significantly improving the textural properties of the gel.

[0206] like Figure 24 As shown, YP-G-10 / 0 exhibited poor water-holding capacity, at only 14.91%. After adding gelatin, the water-holding capacity of YP-G-9 / 1, YP-G-8 / 2, YP-G-7 / 3, YP-G-6 / 4, and YP-G-5 / 5 were significantly improved, with a positive correlation between water-holding capacity and the proportion of gelatin added. The water-holding capacity ranged from 89.33±0.82% to 99.78±0.01%. Among all samples, the double-protein gel of YP-G-5 / 5 showed the highest water-holding capacity, while the water-holding capacities of YP-G-6 / 4, YP-G-7 / 3, and YP-G-8 / 2 all exceeded 90%. This indicates that the three-dimensional network structure constructed with gelatin possesses stable water-binding capabilities.

[0207] The above results indicate that YP-G250 exhibits the best overall performance when the ratio of yeast protein to gelatin is 5:5.

[0208] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for the preparation of a thermoreversible gel, characterized in that, include: The modified yeast protein solution and gelatin solution were mixed; The solubility of modified yeast protein is 48%–53%; Gelatin has a Bloom value of 220–260.

2. The production method according to claim 1, characterized by, The mass ratio of the modified yeast protein to the gelatin is (1-9):

1.

3. The production method according to claim 2, characterized by, The modified yeast protein concentration in the modified yeast protein solution is 0.04 g / mL to 0.06 g / mL, and / or the gelatin concentration in the gelatin solution is 0.04 g / mL to 0.06 g / mL.

4. The process according to any one of claims 1 to 3, characterized in that, The modified yeast protein is obtained by modifying yeast protein with a pulsed electric field.

5. The preparation method according to claim 4, characterized in that, The yeast protein has a protein content of ≥84%wt and a moisture content of ≤4%wt.

6. The production method according to claim 4 or 5, characterized by, The method for modifying the pulsed electric field includes: A yeast protein solution with an electrical conductivity of 2.9 mS / cm to 3.1 mS / cm was placed in a pulsed electric field for modification. The conditions of the pulsed electric field included an electric field strength of 18 kV / cm to 22 kV / cm. Preferably, the conditions for the pulsed electric field further include: a pulse width of 8 μs to 12 μs, and / or an electric field frequency of 480 Hz to 520 Hz; More preferably, the conditions for the pulsed electric field further include: an effective processing time of 0.6 ms to 1.0 ms, and / or an actual processing time of 7 min to 9 min.

7. The process according to any one of claims 1 to 6, characterized in that, The modified yeast protein solution and gelatin solution were mixed at a temperature of 40℃~50℃.

8. The process according to any one of claims 1 to 7, characterized in that, The Bloom value of the gelatin is 230-250.

9. A thermoreversible gel, characterized in that, It is prepared by the method described in any one of claims 1 to 8; Preferably, the thermoreversible gel corresponds to level 5 to 7 of the International Dietary Standards for Dysphagia, and more preferably level 6.

10. The application of the thermally reversible gel of claim 9 as a food, a food matrix, or a food additive; Preferably, the food, food matrix, or food additive is suitable for people with swallowing disorders.

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