Preparation method of high-protein high-calcium soft food

Abstract

The invention discloses a preparation method of a high-protein high-calcium soft food, and belongs to the technical field of natural food processing. On the basis of mixing the high-concentration whey protein isolate aqueous solution and the pectin solution, calcium chloride is added, and the high-calcium high-protein instant texture-improved food is prepared. According to the method, a new compound is constructed by utilizing relatively weak electrostatic attraction force of polysaccharide and protein around an isoelectric point of the polysaccharide and the protein, the development of high-calcium high-protein structure improved food with low viscosity, good fluidity and high uniformity is realized in one step by regulating and controlling the electrostatic bonding strength between the polysaccharide and the protein, and the operation steps are simple, efficient and practical.

Description

Technical Field

[0001] The invention relates to a method for preparing high-protein and high-calcium soft food, belonging to the technical field of natural food processing. Background Art

[0002] The content of whey protein isolate in milk is second only to casein, accounting for about 18-20% of the total mass of milk protein. It mainly includes β-lactoglobulin, α-lactalbumin, bovine serum albumin, immunoglobulin, lactoferrin, etc.; among them, β-lactoglobulin and α-lactalbumin account for 50% and 20% of the total whey protein content respectively, and play a dominant role in the functional properties of whey protein isolate.

[0003] Due to the excellent balance of whey protein amino acid composition, good solubility and outstanding biological efficacy, it is the first choice for dietary protein supplementation for specific groups of people (such as fitness enthusiasts and people with dysphagia) and an important ingredient for protein-based beverages and fermented foods. As people age, they begin to lose bone calcium and their bone density gradually decreases. Calcium supplementation can help reduce bone problems. Since the Oriental diet lacks foods rich in calcium, it is usually difficult for us to get enough calcium in the existing diet and we need to take additional calcium supplements.

[0004] A large number of studies have shown that semi-solid and liquid protein-based foods are easier to digest and absorb by the human body than solid protein-based foods. However, when the whey protein aqueous solution is heated when the protein content is greater than 4%, it will form a "solid" gel state, and the addition of calcium ions will further increase the gel strength, making the current high-calcium and high-protein fluid foods all "ready-to-use" types, and there are few commercial products that can be stored at room temperature for a long shelf life.

[0005] At present, the most common commercially available high-calcium and high-protein fluid products are high-protein yogurt. For example: Patent CN108064940A discloses a method for preventing high-protein yogurt from agglomerating; Patent CN114052076B discloses a process for preparing high-protein yogurt, which uses a refinement device to prepare yogurt with a protein content of 4 to 10%; Patent CN114052260A discloses a method for using pectin and carboxymethyl cellulose aqueous solution to adjust pH and inhibit thermal gelation of protein, but the protein content in this method is still low, only 6 to 12%, which cannot meet the demand for high-protein instant fluid food.

[0006] Moreover, the processing of high-concentration whey protein fermented food needs to inactivate the non-probiotics in the system before inoculating probiotics, and traditional heat sterilization process also can cause protein gelation, thus is unfavorable for the dispersion of probiotics after inoculation and the uniformity of subsequent fermentation. Although some "cold sterilization" modes (such as high-density carbon dioxide, high static pressure, high-voltage pulse electric field, etc.) are processed and have certain effects, these technologies are not yet formed into large-scale applications due to high investment cost and maturity. Therefore, how to efficiently suppress the gelation of whey protein in high-temperature heating sterilization process is the prerequisite for developing high-calcium high-concentration protein-based fluid food and its derivative products.

[0007] In summary, in order to address the challenge of easy gelation of whey protein aqueous solution during heating, it is necessary to seek new methods to inhibit its gelation. It is of great significance to prepare high-concentration protein liquid food products to meet the demand for high-protein instant fluid food. Further exploration of effective solutions is needed to promote the development and application of high-protein liquid food products. Summary of the invention

[0008] [Technical issues]

[0009] High-concentration protein aqueous solutions will form a gel state after high-temperature heating treatment, which is a bottleneck problem in the development of high-protein fluid foods. Especially near the isoelectric point of the protein, due to the weak electrostatic repulsion between molecules, the protein concentration formed by heat-induced gel is low, and the addition of calcium ions will lead to an increase in the degree of protein aggregation.

[0010] [Technical solution]

[0011] In view of the above problems, the present invention adds calcium chloride to a mixture of a high-concentration whey protein isolate aqueous solution and a polysaccharide solution to prepare a ready-to-eat food with improved texture of high calcium and high protein. The present invention utilizes the weak electrostatic attraction of polysaccharides and proteins around their isoelectric points to construct a new complex, and by regulating the electrostatic binding strength between the two, the development of a high-calcium and high-protein food with improved texture of low viscosity, good fluidity and high uniformity is achieved in one step, and the operation steps are simple, efficient and practical.

[0012] The first object of the present invention is to provide a method for preparing a high-protein and high-calcium soft food, comprising the following steps:

[0013] Mixing a whey protein isolate aqueous solution and a polysaccharide solution to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the polysaccharide in the mixture solution is 8 to 10:1, and the concentration of the whey protein is 130 to 300 g / L;

[0014] The pH of the mixture solution is adjusted to 4.5-5.0, and calcium chloride is added to the mixture solution to make the concentration of calcium chloride in the mixture solution 50-200 mM, and the mixture is heated and stirred to prepare a high-protein and high-calcium soft food.

[0015] Unless otherwise specified, the unit of w / v in the experimental scheme of the present invention is g / L, and the conversion relationship between w / v and g / L is 1% w / v=10 g / L.

[0016] In one embodiment, the pH is adjusted using a hydrochloric acid solution or an aqueous citric acid solution.

[0017] In one embodiment, the concentration of whey protein isolate in the whey protein isolate aqueous solution is 500 g / L, and the solvent is water.

[0018] In one embodiment, the concentration of the polysaccharide in the polysaccharide solution is 50 g / L, and the solvent is water.

[0019] In one embodiment, the polysaccharide in the polysaccharide solution is one or both of high methoxy pectin and sodium carboxymethyl cellulose.

[0020] In one embodiment, the method for preparing the whey protein isolate aqueous solution comprises the following steps:

[0021] The whey protein isolate powder is slowly added into water, stirred at room temperature (20-25° C.) and 600-700 rpm for 2-3 hours to make it uniformly dispersed in the water, and placed in a refrigerator at 2-6° C. overnight (10-12 hours) to ensure that the whey protein isolate is fully hydrated, thereby preparing a whey protein isolate aqueous solution.

[0022] In one embodiment, the method for preparing the polysaccharide solution comprises the following steps:

[0023] The polysaccharide powder was slowly added into water, stirred at 1000-1200 rpm for 2-3 hours in a 75-80°C water bath to make it evenly dispersed in the water, and placed in a 2-6°C refrigerator overnight (10-12 hours) to ensure that the polysaccharide was fully hydrated to prepare a polysaccharide solution.

[0024] In one embodiment, the whey protein isolate is commercially available whey powder.

[0025] In one embodiment, the pectin is commercially available high methoxyl pectin.

[0026] In one embodiment, the pH is adjusted using a 0.1-1 mol / L hydrochloric acid solution or a citric acid aqueous solution, and the solvent of the solution is water.

[0027] In one embodiment, the heating and stirring is 85-95° C. and stirring for 25-30 min.

[0028] In one embodiment, a method for preparing a high-protein and high-calcium soft food comprises the following steps:

[0029] A whey protein isolate aqueous solution and a pectin aqueous solution are mixed to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the polysaccharide in the mixture solution is 8 to 10:1, and a mixture solution containing 132 to 150 g / L of whey protein isolate and 13 to 15 g / L of pectin is obtained, and a 0.1 to 1 mol / L hydrochloric acid solution or a citric acid aqueous solution is used to adjust the pH of the mixture solution to 4.5 to 4.8; calcium chloride is added to the mixture solution to make the calcium chloride concentration in the mixture solution 50 to 200 mM, and the mixture solution is heated and stirred at 85 to 95° C. for 25 to 30 minutes to prepare a high-protein and high-calcium soft food;

[0030] Among them, the viscosity of high-protein and high-calcium soft foods is below 500mPa·s.

[0031] In one embodiment, a method for preparing a high-protein and high-calcium soft food comprises the following steps:

[0032] A whey protein isolate aqueous solution and a pectin aqueous solution are mixed to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the polysaccharide in the mixture solution is 8 to 10:1, and a mixture solution containing 150 to 200 g / L of whey protein isolate and 15 to 20 g / L of pectin is obtained; a 0.1 to 1 mol / L hydrochloric acid solution or a citric acid aqueous solution is used to adjust the pH of the mixture solution to 4.5 to 4.8; calcium chloride is added to the mixture solution to make the concentration of calcium chloride in the mixture solution 50 to 200 mM, and the mixture solution is heated and stirred at 85 to 95° C. for 25 to 30 minutes to prepare a high-protein and high-calcium soft food;

[0033] Among them, the viscosity of high-protein and high-calcium soft foods is below 900mPa·s.

[0034] In one embodiment, a method for preparing a high-protein and high-calcium soft food comprises the following steps:

[0035] A whey protein isolate solution and a pectin solution are mixed to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the polysaccharide in the mixture solution is 8 to 10:1; a mixture solution containing 220 to 250 g / L of whey protein isolate and 22 to 25 g / L of pectin is obtained, and the pH of the mixture solution is adjusted to 4.5 to 4.8 using a 0.1 to 1 mol / L hydrochloric acid solution or a citric acid aqueous solution; calcium chloride is added to the mixture solution to make the concentration of calcium chloride in the mixture solution 50 to 200 mM, and heated and stirred at 85 to 95° C. for 25 to 30 minutes to prepare a high-protein and high-calcium soft food;

[0036] Among them, the viscosity of high-protein and high-calcium soft foods is below 1190 mPa·s.

[0037] In one embodiment, the high-protein, high-calcium soft foods of different viscosities and textures can meet the needs of different groups of people; when the concentration of whey protein isolate in the mixture solution is 132-150 g / L, the sample is in a fluid state and can be drunk directly; when the concentration of whey protein isolate in the mixture solution is 150-250 g / L, the sample has a yogurt texture and can be eaten with a spoon.

[0038] The second object of the present invention is to provide a high-protein and high-calcium soft food prepared by any of the above methods.

[0039] In one embodiment, the high-protein and high-calcium soft food has the characteristics of high calcium, high protein, soft texture, and can be stored at room temperature.

[0040] In one embodiment, the high-protein and high-calcium soft food has a room temperature shelf life of more than 6 months.

[0041] The third object of the present invention is to provide the application of the high-protein and high-calcium soft food in the food field.

[0042] In one embodiment, the high-protein and high-calcium soft food is used to prepare soft gels and liquid foods.

[0043] A fourth object of the present invention is to provide a method for improving the texture of protein food, comprising the following steps:

[0044] Mixing a whey protein isolate aqueous solution and a polysaccharide solution to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the polysaccharide in the mixture solution is 8 to 10:1, and the concentration of the whey protein is 130 to 300 g / L;

[0045] The pH of the mixture solution is adjusted to 4.5-5.0, and calcium chloride is added to the mixture solution to make the concentration of calcium chloride in the mixture solution 50-200 mM, and the mixture is heated and stirred to prepare a protein product with improved texture.

[0046] A fifth object of the present invention is to provide a method for inhibiting the thermal gelation of high-concentration whey protein, comprising the steps of:

[0047] Mixing a whey protein isolate aqueous solution and a polysaccharide solution to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the polysaccharide in the mixture solution is 8 to 10:1, and the concentration of the whey protein is 130 to 300 g / L;

[0048] The pH of the mixture solution is adjusted to 4.5-5.0, and calcium chloride is added to the mixture solution to make the concentration of calcium chloride in the mixture solution 50-200 mM, and the mixture is heated and stirred to prepare a high-concentration whey protein food with weak gel property.

[0049] [Beneficial Effects]

[0050] The invention prepares a high-calcium and high-protein ready-to-eat texture-improved food by mixing a whey protein isolate aqueous solution and a pectin solution in a mass ratio of 8 to 10:1, adjusting the pH to 4.5 to 5.0, and adding 50 to 200 mM calcium chloride.

[0051] Specific:

[0052] (1) The protein content of the high-protein and high-calcium soft food prepared by the present invention reaches 150-250 g / L; and the texture is good, and the protein content is much higher than 120 g / L reported by the existing method; when the protein content is 150 g / L, the viscosity is 381 mPa·s, the texture is 45.8 Pa, and the friction coefficient is 0.0087, which is more conducive to swallowing;

[0053] (2) After high-temperature treatment, the high-protein and high-calcium soft food prepared by the present invention can be stored at room temperature for a long time without adding any preservatives;

[0054] (3) The polysaccharides selected in the present invention are all soluble dietary fibers used as required by national standards, without any potential safety hazards, without any other additives, and with simple ingredients;

[0055] (4) Compared with other "cold sterilization" methods, the method of the present invention does not require new equipment investment and is low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 The sample morphology after high-temperature heat treatment; from left to right are the ready-to-eat texture-improved foods prepared in Comparative Example 1 and Example 1;

[0057] Figure 2 The sample morphology after high-temperature heat treatment; from left to right are the ready-to-eat texture-improved foods prepared in Comparative Example 2, Comparative Example 3, and Example 2;

[0058] Figure 3 It is the sample morphology after high-temperature heat treatment; from left to right are Comparative Example 4, Comparative Example 5, and Example 3 prepared ready-to-eat foods with improved texture. DETAILED DESCRIPTION

[0059] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0060] The raw materials used in the embodiment:

[0061] Whey protein isolate powder: purchased from Hilmar, USA, model 9410;

[0062] Pectin: high methoxyl pectin, purchased from Dongkang Biology, food grade;

[0063] Calcium chloride: purchased from Jiahe Xuri, food grade.

[0064] Test method:

[0065] 1. Texture testing method:

[0066] Experimental instrument: rotational rheometer, AntonPaar MCR302;

[0067] Frequency scanning range: 0.1~100rad / s, strain 0.5%;

[0068] Experimental method: Place the test sample on the base of the rheometer and then perform a frequency sweep. The frequency sweep range is 0.1-100 rad / s, the strain is set to 0.5%, the temperature is 25°C, a 50mm plate (PP50) is selected, and the gap between the plate and the base is set to 1mm.

[0069] 2. Viscosity detection method:

[0070] Similarly, the viscosity was tested using a rotational rheometer;

[0071] Experimental method: Place the test sample on the base of the rheometer and then perform shear scanning. The shear rate range is 0.1-100 rad / s, the strain is set to 0.5%, the temperature is 25°C, a 50mm plate (PP50) is selected, and the gap between the plate and the base is set to 1mm. The viscosity value in the data table is selected at a shear rate of 50s -1 , this rate is often used to classify fluid thickness.

[0072] 3. Lubricity testing method:

[0073] The tribological properties of the samples were measured using a microtraction tester. All friction measurements were performed using a 1N load and a 50% slide-to-roll ratio. The friction coefficients were measured as a function of the entrainment speed, ranging from 1 to 1000 mm / s. The temperature was controlled at 37 ± 1 °C. The friction coefficients in the data table are the test values ​​at an entrainment speed of 1000 mm / s.

[0074] Embodiment 1: Preparation method of high-protein and high-calcium soft food

[0075] A method for preparing a high-protein and high-calcium soft food comprises the following steps:

[0076] (1) Mixing whey protein isolate powder with water, stirring at 600 rpm for 2 h to uniformly disperse it in the water, preparing a 500 g / L whey protein isolate aqueous solution, and placing it in a 4° C. refrigerator overnight;

[0077] Pectin was mixed with water, and stirred at 1000 rpm for 2 h in a water bath at 80°C to uniformly disperse the mixture in water, thereby preparing a 50 g / L polysaccharide solution;

[0078] (2) Mixing a whey protein isolate aqueous solution and a polysaccharide solution to obtain a mixture solution; wherein the mass ratio of whey protein isolate to pectin in the mixture solution is 10:1, the concentration of whey protein isolate is 150 g / L, and the concentration of pectin is 15 g / L; stirring for 2 hours and adjusting the pH to 4.6 using a 1 mol / L citric acid aqueous solution; adding calcium chloride to the mixture solution so that the concentration of calcium chloride in the mixture solution is 50 mM, and stirring for 30 minutes; and heating at 90° C. for 30 minutes after stirring to prepare a high-protein and high-calcium soft food.

[0079] Embodiment 2: Preparation method of high-protein and high-calcium soft food

[0080] On the basis of Example 1, the concentration of whey protein isolate in the mixture solution of step (2) was changed to 200 g / L, and the concentration of pectin was changed to 20 g / L. The remaining steps were kept consistent with Example 1 to prepare a high-protein and high-calcium soft food.

[0081] Example 3: Preparation method of high-protein and high-calcium soft food

[0082] On the basis of Example 1, the concentration of whey protein isolate in the mixture solution of step (2) was changed to 250 g / L, and the concentration of pectin was changed to 25 g / L. The remaining steps were kept consistent with Example 1 to prepare a high-protein and high-calcium soft food.

[0083] Tested on:

[0084] The sealed high-protein and high-calcium soft foods prepared in Examples 1 to 3 have a shelf life of more than 6 months at room temperature.

[0085] Comparative Example 1: Preparation of high calcium and high protein food using whey protein isolate and calcium chloride

[0086] The high calcium and high protein food is prepared by using whey protein isolate and calcium chloride. The specific steps are as follows:

[0087] (1) Mixing whey protein isolate powder with water, stirring at 600 rpm for 2 h to uniformly disperse it in the water, preparing a 500 g / L whey protein isolate aqueous solution, and placing it in a 4° C. refrigerator overnight;

[0088] (2) diluting the prepared whey protein isolate aqueous solution to obtain an aqueous solution containing 150 g / L whey protein isolate, stirring for 2 h and adjusting the pH to 4.6 using a 1 mol / L citric acid aqueous solution to obtain a mixture solution; adding calcium chloride to the mixture solution to make the concentration of calcium chloride in the mixture solution 50 mM, and stirring for 30 min; and heating at 90° C. for 30 min after stirring to prepare a high-calcium and high-protein food.

[0089] Comparative Example 2: Preparation of high calcium and high protein food using whey protein isolate and calcium chloride

[0090] On the basis of Comparative Example 1, the concentration of whey protein isolate in step (2) was changed to 200 g / L, and the remaining steps were kept consistent with Comparative Example 1 to prepare a high-calcium and high-protein food.

[0091] Comparative Example 3: Calcium chloride is added before pectin

[0092] Based on Example 2, step (2) is changed to:

[0093] Add 50 mM calcium chloride to the whey protein isolate aqueous solution and stir for 30 minutes to obtain a calcium chloride whey protein isolate aqueous solution;

[0094] The calcium chloride whey protein isolate aqueous solution and the polysaccharide solution are mixed to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the pectin in the mixture solution is 10:1, the concentration of the whey protein isolate is 200 g / L, and the concentration of the pectin is 20 g / L; stirring for 30 minutes, heating at 90° C. for 30 minutes after stirring, and preparing a high-calcium and high-protein food.

[0095] Comparative Example 4: Preparation of high calcium and high protein food using whey protein isolate and calcium chloride

[0096] On the basis of Comparative Example 1, the concentration of whey protein isolate in step (2) was changed to 250 g / L, and the remaining steps were kept consistent with Comparative Example 1 to prepare a high-calcium and high-protein food.

[0097] Comparative Example 5: Calcium chloride is added before pectin

[0098] Based on Example 3, step (2) is changed to:

[0099] Add 50 mM calcium chloride to the whey protein isolate aqueous solution and stir for 30 minutes to obtain a calcium chloride whey protein isolate aqueous solution;

[0100] The calcium chloride whey protein isolate aqueous solution and the polysaccharide solution are mixed to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the pectin in the mixture solution is 10:1, the concentration of the whey protein isolate is 250 g / L, and the concentration of the pectin is 20 g / L; stirring for 30 minutes, and heating at 90° C. for 30 minutes after stirring to prepare a high-calcium and high-protein food.

[0101] Example 4: Texture testing of ready-to-eat foods with improved texture

[0102] The high calcium and high protein foods prepared in Examples 1 to 3 and Comparative Examples 1 to 5 were taken and their texture data were tested.

[0103] The high calcium and high protein food prepared in Comparative Example 1 and Example 1 is as follows Figure 1 As shown; Comparative Example 2, Comparative Example 3, Example 2 prepared high calcium and high protein food morphology as shown Figure 2 As shown; Comparative Example 4, Comparative Example 5, Example 3 prepared high calcium and high protein food morphology as shown Figure 3 shown.

[0104] The texture data of the high-calcium and high-protein foods prepared in Examples 1 to 3 and Comparative Examples 1 to 3 are shown in Table 1.

[0105] Table 1 Texture data of ready-to-eat texture-improved foods

[0106] Grouping Storage modulus G'(Pa) Viscosity (mPa·s) Friction coefficient (-) Comparative Example 1 3790 / / Comparative Example 2 6860 / / Comparative Example 3 5320 5190 0.0458 Comparative Example 4 10400 / / Comparative Example 5 5750 6150 0.0505 Example 1 45.8 381 0.0087 Example 2 194 973 0.0133 Example 3 260 2210 0.0265

[0107] Note: “ / ” means the food is in a hard solid state and is sheared and broken, so the relevant data cannot be measured

[0108] The results show that compared with Comparative Examples 1 to 5, the storage modulus of Examples 1 to 3 is significantly reduced, and the gel strength is greatly reduced. Comparing Comparative Examples 2 and 3; Comparative Examples 4 and 5, it can be seen that the addition of pectin can reduce the gel strength, but compared with Examples 2 and 3, the gel strength is still relatively high and the texture is still hard. Changing the timing of adding calcium chloride (adding after pectin, Examples 1 to 3) can significantly reduce the gel strength, improve the texture of high-protein gel, reduce the gel strength, and reduce the friction coefficient. The lubrication performance is improved, which can reduce the adsorption residue in the throat and is more conducive to swallowing.

[0109] The high-protein, high-calcium soft foods of different viscosities and textures prepared in Examples 1 to 3 can meet the needs of different groups of people; when the concentration of whey protein isolate in the mixed solution is lower than 150 g / L, the sample is in a fluid state and can be drunk directly; when the concentration of whey protein isolate in the mixed solution is 150 to 250 g / L, the sample has a yogurt texture and can be eaten with a spoon.

[0110] Example 5

[0111] The pectin in Example 1 was adjusted to sodium carboxymethyl cellulose, and the other parts were kept consistent with Example 1 to obtain a high-protein and high-calcium soft food.

[0112] Example 6

[0113] The citric acid aqueous solution in Example 1 was adjusted to a hydrochloric acid solution, and the other aspects were kept consistent with Example 1 to obtain a high-protein and high-calcium soft food.

[0114] The obtained high-protein and high-calcium soft food was subjected to performance testing, and the test results are as follows:

[0115] High-protein, high-calcium soft foods are in a fluid state and can be drunk directly; they can be sealed and have a shelf life of more than 6 months at room temperature.

[0116] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing a high-protein and high-calcium soft food, characterized in that: The steps include: Mixing a whey protein isolate aqueous solution and a polysaccharide solution to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the polysaccharide in the mixture solution is 8 to 10:1, and the concentration of the whey protein is 130 to 300 g / L; The pH of the mixture solution is adjusted to 4.5-5.0, and calcium chloride is added to the mixture solution to make the concentration of calcium chloride in the mixture solution 50-200 mM, and the mixture is heated and stirred to prepare a high-protein and high-calcium soft food.

2. The preparation method according to claim 1, characterized in that: The polysaccharide in the polysaccharide solution is one or two of high methoxy pectin and sodium carboxymethyl cellulose, and the solvent is water.

3. The preparation method according to claim 1, characterized in that: The heating and stirring is at 85-95°C for 25-30 minutes.

4. The preparation method according to claim 1, characterized in that: The preparation method of the whey protein isolate aqueous solution comprises the following steps: The whey protein isolate powder was slowly added into water, stirred at 600-700 rpm for 2-3 hours to make it evenly dispersed in the water, and placed at 2-6° C. overnight to prepare a whey protein isolate aqueous solution.

5. The preparation method according to claim 1, characterized in that: The preparation method of the polysaccharide solution comprises the following steps: The polysaccharide powder was slowly added into water, stirred at 1000-1200 rpm for 2-3 hours in a 75-80° C. water bath to make it uniformly dispersed in the water, and placed in a 2-6° C. refrigerator for 10-12 hours to prepare a polysaccharide solution.

6. A high-protein and high-calcium soft food prepared by the method according to any one of claims 1 to 5.

7. Use of the high-protein and high-calcium soft food according to claim 6 in the food field.

8. The use according to claim 7, characterized in that: High-protein and high-calcium soft foods are used to prepare soft gels and liquid meals.

9. A method for improving the texture of protein food, characterized in that: The steps include: Mixing a whey protein isolate aqueous solution and a polysaccharide solution to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the polysaccharide in the mixture solution is 8 to 10:1, and the concentration of the whey protein is 130 to 300 g / L; The pH of the mixture solution is adjusted to 4.5-5.0, and calcium chloride is added to the mixture solution to make the concentration of calcium chloride in the mixture solution 50-200 mM, and the mixture is heated and stirred to prepare a protein food with improved texture.

10. A method for inhibiting thermal gelation of high-concentration whey protein, characterized in that: The steps include: Mixing a whey protein isolate aqueous solution and a polysaccharide solution to obtain a mixture solution; wherein the mass ratio of the whey protein isolate to the polysaccharide in the mixture solution is 8 to 10:1, and the concentration of the whey protein is 130 to 300 g / L; The pH of the mixture solution is adjusted to 4.5-5.0, and calcium chloride is added to the mixture solution to make the concentration of calcium chloride in the mixture solution 50-200 mM, and the mixture is heated and stirred to prepare a high-concentration whey protein food with weak gel property.

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