Milk-based solid beverage and preparation method thereof

Abstract

The invention discloses a milk-based solid beverage and a preparation method thereof, and relates to the technical field of solid beverages. The invention discloses a preparation method of a milk-based solid beverage, which comprises the following steps: blending raw materials according to a formula ratio to obtain the milk-based solid beverage, the milk-based solid beverage contains 1-7wt% of a calcium supplement; the calcium supplement is obtained by carrying out covalent cross-linking on carboxymethylated beta-glucan and sodium alginate and then carrying out calcium chelation treatment; plant polysaccharide oat beta-glucan is used as a raw material, the oat beta-glucan is subjected to carboxymethylation treatment and then is covalently cross-linked with carboxymethyl sodium alginate to construct a three-dimensional network, the high efficiency and stability of the product are ensured, finally calcium ions are chelated, and the calcium supplement of the solid beverage is prepared. The prepared calcium supplement is high in calcium content and easy to absorb by intestines and stomach.

Description

Technical Field

[0001] The present invention relates to the technical field of solid beverages, and particularly relates to a milk-based solid beverage and a preparation method thereof. Background Art

[0002] Calcium is the most abundant metallic element in the human body. 99% of the calcium in the human body exists in the form of hydroxyapatite in the bones, making it one of the main bone-forming minerals. Calcium can not only provide strength and support for the bones, but also participate in various metabolic processes in the human body, such as blood coagulation, cell adhesion, muscle contraction, activation of enzyme reactions, cell proliferation and differentiation, etc. Therefore, the human body needs to intake an appropriate amount of calcium every day. Among them, the recommended calcium intake for adults is 800 mg / d, and the recommended calcium intake for children, adolescents, lactating or pregnant women is 1200 mg / d. Statistics show that the actual calcium intake of Chinese residents is about 350 mg / d. The human body intakes calcium through diet. Insufficient calcium intake will lead to bone mass reduction or osteoporotic fractures, and will also increase the risks of kidney stones and colon cancer. There are many types of calcium supplementation products on the market. The earliest calcium preparations used in China are inorganic calcium such as calcium carbonate and calcium chloride, which have a high calcium content and a low price, but are difficult to be absorbed by the gastrointestinal tract. Subsequently, organic acid calcium such as calcium lactate and calcium gluconate appeared. The solubility of organic acid calcium is enhanced, but the calcium content is less and the utilization rate is low, and a large amount needs to be taken. In addition, calcium gluconate has a high sugar content and is not conducive to diabetic patients, while calcium lactate will cause human fatigue due to lactate deposition. Amino acid chelated calcium can overcome the disadvantages of inorganic calcium and organic acid calcium, but the production cost is high and the preparation process is also more complex.

[0003] Solid beverages belong to a category of soft drinks and are mainly divided into protein-type solid beverages and ordinary solid beverages. Protein-type solid beverages refer to products made mainly from milk and dairy products, eggs and egg products, etc., with or without the addition of auxiliary materials, and the protein content is greater than or equal to 4%. Common products include soy milk powder, walnut powder, malted milk essence, etc. Adding calcium supplements to solid beverages can effectively improve the nutritional components of the beverages. However, the existing calcium supplements are directly added to solid beverages, and after later brewing, the dispersion stability of the calcium supplements in the beverages is poor. Summary of the Invention

[0004] The purpose of the present invention is to provide a milk-based solid beverage and a preparation method thereof, and solve the following technical problems: The existing calcium supplements are directly added to solid beverages, and after later brewing, the dispersion stability of the calcium supplements in the beverages is poor.

[0005] The purpose of the present invention can be achieved by the following technical solutions: A preparation method of a milk-based solid beverage, comprising the following steps: blending the raw materials in formula amounts to obtain a milk-based solid beverage; the milk-based solid beverage contains 1-7 wt% of calcium supplements; The preparation method of the calcium supplement comprises the following steps: S1: Blend carboxymethylated β-glucan and PBS buffer solution, add EDC / NHS activator, control the temperature at 25 - 37°C, and activate for 0.5 - 1 h under light-shielded conditions to obtain a carboxymethylated β-glucan ester intermediate; Blend carboxymethylated sodium alginate and PBS buffer solution, add EDC / NHS activator, control the temperature at 25 - 37°C, and activate for 0.5 - 1 h under light-shielded conditions to obtain a carboxymethylated sodium alginate ester intermediate; Blend the carboxymethylated β-glucan ester intermediate and the carboxymethylated sodium alginate ester intermediate, control the temperature at 25 - 40°C, carry out a heat preservation reaction for 4 - 8 h, add ethanol to terminate the reaction, centrifuge to collect the precipitate, dialyze and purify, and freeze-dry to obtain a polysaccharide material; S2: Blend CaCl2 and water, adjust the pH to 6.5 - 7.5, add the polysaccharide material, control the temperature at 50 - 60°C, carry out a heat preservation stirring for 2 - 4 h, centrifuge to collect the precipitate, wash with water, dialyze and purify, and freeze-dry to obtain a calcium supplement.

[0006] As a further scheme of the present invention: The EDC / NHS activator is composed of EDC and NHS with a molar ratio of 1:1 - 2; The addition ratio of carboxymethylated β-glucan, PBS buffer solution, and EDC / NHS activator is 1 g:50 - 100 mL:0.15 - 0.45 g; The addition ratio of carboxymethylated sodium alginate, PBS buffer solution, and EDC / NHS activator is 1 g:50 - 100 mL:0.15 - 0.45 g; The mass ratio of the carboxymethylated β-glucan used in the preparation of the carboxymethylated β-glucan ester intermediate to the carboxymethylated sodium alginate used in the carboxymethylated sodium alginate ester intermediate is 1:1 - 1.2.

[0007] As a further scheme of the present invention: The addition ratio of CaCl2, water, and the polysaccharide material in S2 is 2 - 5 g:100 - 200 mL:1 g.

[0008] As a further scheme of the present invention: The preparation method of carboxymethylated oat β-glucan comprises the following steps: Blend oat β-glucan and NaOH solution, add chloroacetic acid, control the temperature at 50 - 60°C, carry out a heat preservation reaction for 3 - 5 h under stirring conditions, purify, and freeze-dry to obtain carboxymethylated β-glucan.

[0009] As a further scheme of the present invention: The NaOH solution is a 2 - 4 mol / L NaOH aqueous solution; the addition ratio of oat β-glucan, NaOH solution, and chloroacetic acid is 1 g:50 - 100 mL:0.8 - 1.2 g.

[0010] As a further solution of the present invention: The preparation method of carboxymethylated sodium alginate comprises the following steps: Mix sodium alginate and NaOH solution, add chloroacetic acid, control the temperature at 50 - 70°C, keep the reaction under stirring conditions for 2 - 4 h, adjust the pH to neutral, pour the reaction solution into ethanol for precipitation, collect the precipitate by centrifugation, purify by dialysis, and freeze-dry to obtain carboxymethylated sodium alginate.

[0011] As a further solution of the present invention: The NaOH solution is 2 - 4 mol / L NaOH aqueous solution; the addition ratio of sodium alginate, NaOH solution, and chloroacetic acid is 1 g : 20 - 40 mL : 0.3 - 0.8 g.

[0012] As a further solution of the present invention: The milk-based solid beverage comprises the following raw materials in weight percentages: sweet whey powder 12 - 15%, milk powder 5 - 8%, hydrogenated palm kernel oil 30 - 35%, glucose syrup 42 - 48%, sodium caseinate 1.5 - 2.2%, dipotassium hydrogen phosphate 1.3 - 1.8%, compound emulsifier 1.2 - 1.9%, calcium supplement 1 - 7%; the sum of the weight percentages of each raw material is 100%.

[0013] As a further solution of the present invention: The compound emulsifier is composed of monoglyceride and diglyceride fatty acid esters and diacetyl tartaric acid monoglyceride; the monoglyceride and diglyceride fatty acid esters account for 1 - 1.5% of the total mass of the milk-based solid beverage, and the diacetyl tartaric acid monoglyceride accounts for 0.2 - 0.4% of the total mass of the milk-based solid beverage; the milk powder is skim milk powder.

[0014] A milk-based solid beverage is prepared by the preparation method of any one of the above.

[0015] The beneficial effects of the present invention: In this application, oat β-glucan, a plant polysaccharide, is selected as the raw material, and then natural polysaccharide sodium alginate is added; the two polysaccharides are respectively carboxymethylated to obtain carboxymethylated oat β-glucan and carboxymethylated sodium alginate; the carboxymethylated oat β-glucan and carboxymethylated sodium alginate are crosslinked by EDC / NHS, and the activated carboxyl group forms an ester bond with the hydroxyl group of another polysaccharide, which is easy to construct a three-dimensional network structure to obtain a polysaccharide material; finally, a stable chelate is formed between the carboxylate group of the polysaccharide material and calcium to obtain a calcium supplement. The calcium supplement prepared in this application effectively avoids gastric acid precipitation, targets intestinal release, and improves the absorption efficiency of the human body. In this application, carboxymethylated oat β-glucan and sodium alginate are covalently crosslinked and then calcium chelation is carried out to improve the compatibility of the polysaccharides and the uniformity of subsequent calcium chelation. This application uses two polysaccharides to composite and construct a crosslinked network, effectively realizing the slow-release effect of calcium ions, improving the absorption efficiency, and oat β-glucan itself has the function of dietary fiber, which can synergistically promote calcium absorption. Specific embodiments

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] Example 1 The preparation method of the calcium supplement comprises the following steps: S1: Mix 1 g of oat β-glucan and 50 mL of 2 mol / L NaOH aqueous solution, add 0.8 g of chloroacetic acid, control the temperature at 50 °C, and keep the reaction under stirring for 3 h. Then, purify and freeze-dry to obtain carboxymethylated β-glucan; Mix 1 g of sodium alginate and 20 mL of 2 mol / L NaOH aqueous solution, add 0.3 g of chloroacetic acid, control the temperature at 50 °C, and keep the reaction under stirring for 2 h. Adjust the pH to neutral with dilute hydrochloric acid, pour the reaction solution into ethanol for precipitation, collect the precipitate by centrifugation, purify by dialysis, and freeze-dry to obtain carboxymethylated sodium alginate; S2: Mix 1 g of carboxymethylated β-glucan and 50 mL of PBS buffer solution (0.1 M, pH 5.5), add 0.15 g of EDC / NHS activator (the molar ratio of EDC to NHS is 1:1), control the temperature at 25 °C, and activate under light-shielded conditions for 0.5 h to obtain a carboxymethylated β-glucan ester intermediate; Mix 1 g of carboxymethylated sodium alginate and 50 mL of PBS buffer solution (0.1 M, pH 5.5), add 0.15 g of EDC / NHS activator (the molar ratio of EDC to NHS is 1:1), control the temperature at 25 °C, and activate under light-shielded conditions for 0.5 h to obtain a carboxymethylated sodium alginate ester intermediate; Mix the above-prepared carboxymethylated β-glucan ester intermediate and carboxymethylated sodium alginate ester intermediate, control the temperature at 25 °C, and keep the reaction for 4 h. Add ethanol to terminate the reaction, collect the precipitate by centrifugation, purify by dialysis, and freeze-dry to obtain a polysaccharide material; S3: Mix 2 g of CaCl2 and 100 mL of water, adjust the pH to 6.5, add 1 g of the polysaccharide material, control the temperature at 50 °C, and keep stirring for 2 h. Collect the precipitate by centrifugation, wash with water, purify by dialysis, and freeze-dry to obtain the calcium supplement.

[0018] Example 2 The preparation method of the calcium supplement comprises the following steps: S1: Mix 1 g of oat β-glucan and 70 mL of 2 mol / L NaOH aqueous solution, add 1 g of chloroacetic acid, control the temperature at 55 °C, and keep the reaction under stirring for 4 h. Then, purify and freeze-dry to obtain carboxymethylated β-glucan; Mix 1 g of sodium alginate and 30 mL of 2 mol / L aqueous sodium hydroxide solution, add 0.5 g of chloroacetic acid, control the temperature at 60 °C, keep the reaction under stirring for 3 h, adjust the pH to neutral with dilute hydrochloric acid, pour the reaction solution into ethanol for precipitation, collect the precipitate by centrifugation, purify by dialysis, and freeze-dry to obtain carboxymethylated sodium alginate; S2: Mix 1 g of carboxymethylated β-glucan and 70 mL of PBS buffer solution (0.1 M, pH 5.5), add 0.3 g of EDC / NHS activator (the molar ratio of EDC to NHS is 1:1), control the temperature at 30 °C, and activate for 0.5 h under light-shielded conditions to obtain a carboxymethylated β-glucan ester intermediate; Mix 1 g of carboxymethylated sodium alginate and 70 mL of PBS buffer solution (0.1 M, pH 5.5), add 0.3 g of EDC / NHS activator (the molar ratio of EDC to NHS is 1:1), control the temperature at 30 °C, and activate for 0.5 h under light-shielded conditions to obtain a carboxymethylated sodium alginate ester intermediate; Mix the above-prepared carboxymethylated β-glucan ester intermediate and carboxymethylated sodium alginate ester intermediate, control the temperature at 35 °C, keep the reaction for 6 h, add ethanol to terminate the reaction, collect the precipitate by centrifugation, purify by dialysis, and freeze-dry to obtain a polysaccharide material; S3: Mix 2 g of CaCl2 and 150 mL of water, adjust the pH to 7, add 1 g of the polysaccharide material, control the temperature at 55 °C, keep stirring for 3 h, collect the precipitate by centrifugation, wash with water, purify by dialysis, and freeze-dry to obtain a calcium supplement.

[0019] Example 3 The preparation method of the calcium supplement includes the following steps: S1: Mix 1 g of oat β-glucan and 100 mL of 2 mol / L aqueous sodium hydroxide solution, add 1.2 g of chloroacetic acid, control the temperature at 60 °C, keep the reaction under stirring for 5 h, purify, and freeze-dry to obtain carboxymethylated β-glucan; Mix 1 g of sodium alginate and 40 mL of 2 mol / L aqueous sodium hydroxide solution, add 0.8 g of chloroacetic acid, control the temperature at 70 °C, keep the reaction under stirring for 4 h, adjust the pH to neutral with dilute hydrochloric acid, pour the reaction solution into ethanol for precipitation, collect the precipitate by centrifugation, purify by dialysis, and freeze-dry to obtain carboxymethylated sodium alginate; S2: Mix 1 g of carboxymethylated β-glucan and 100 mL of PBS buffer solution (0.1 M, pH 5.5), add 0.45 g of EDC / NHS activator (the molar ratio of EDC to NHS is 1:1), control the temperature at 37 °C, and activate for 1 h under light-shielded conditions to obtain a carboxymethylated β-glucan ester intermediate; Mix 1 g of carboxymethylated sodium alginate and 100 mL of PBS buffer (0.1 M, pH 5.5), add 0.45 g of EDC / NHS activator (the molar ratio of EDC to NHS is 1:1), and activate at 37 °C in the dark for 1 h to obtain the carboxymethylated sodium alginate ester intermediate; Mix the prepared carboxymethylated β-glucan ester intermediate and carboxymethylated sodium alginate ester intermediate, control the temperature at 40 °C, keep the temperature and react for 8 h, add ethanol to terminate the reaction, centrifuge to collect the precipitate, dialyze and purify, and freeze-dry to obtain the polysaccharide material; S3: Mix 2 g of CaCl2 and 200 mL of water, adjust the pH to 7.5, add 1 g of the polysaccharide material, control the temperature at 60 °C, keep the temperature and stir for 4 h, centrifuge to collect the precipitate, wash with water, dialyze and purify, and freeze-dry to obtain the calcium supplement.

[0020] Example 4 A method for preparing a milk-based solid beverage, comprising the following steps: Mix the following raw materials in the following formula amounts: 14% sweet whey powder, 6% skim milk powder, 30% hydrogenated palm kernel oil, 46% glucose syrup, 2% sodium caseinate, 1.5% dipotassium hydrogen phosphate, 1.2% mono- and diglycerides, 0.3% monoglyceride diacetyl tartrate, and 3% of the calcium supplement prepared in Example 1 to obtain the milk-based solid beverage.

[0021] Example 5 Compared with Example 4, only the calcium supplement prepared in Example 1 added in Example 4 is replaced with the calcium supplement prepared in Example 2 in equal amounts, and the other components and preparation methods are exactly the same as those in Example 4.

[0022] Example 6 Compared with Example 4, only the calcium supplement prepared in Example 1 added in Example 4 is replaced with the calcium supplement prepared in Example 3 in equal amounts, and the other components and preparation methods are exactly the same as those in Example 4.

[0023] Comparative Example 1 The preparation method of the calcium supplement comprises the following steps: S1: Mix 1 g of oat β-glucan and 70 mL of 2 mol / L NaOH aqueous solution, add 1 g of chloroacetic acid, control the temperature at 55 °C, keep the temperature and react under stirring conditions for 4 h, purify and freeze-dry to obtain carboxymethylated β-glucan; S2: Mix 2 g of CaCl2 and 150 mL of water, adjust the pH to 7, add 1 g of carboxymethylated β-glucan, control the temperature at 55 °C, keep the temperature and stir for 3 h, centrifuge to collect the precipitate, wash with water, dialyze and purify, and freeze-dry to obtain the calcium supplement.

[0024] Comparative Example 2 The preparation method of the calcium supplement comprises the following steps: S1: Mix 1 g of oat β-glucan and 70 mL of 2 mol / L NaOH aqueous solution, add 1 g of chloroacetic acid, control the temperature at 55 °C, and keep the reaction warm under stirring conditions for 4 h. Then, purify and freeze-dry to obtain carboxymethylated β-glucan; Mix 1 g of carboxymethylated β-glucan and 1 g of sodium alginate, control the temperature at 35 °C, and keep the reaction warm for 6 h. Add ethanol to terminate the reaction, centrifuge to collect the precipitate, purify by dialysis, and freeze-dry to obtain the polysaccharide material; S2: Mix 2 g of CaCl2 and 150 mL of water, adjust the pH to 7, add 1 g of the polysaccharide material, control the temperature at 55 °C, and keep stirring warm for 3 h. Centrifuge to collect the precipitate, wash with water, purify by dialysis, and freeze-dry to obtain the calcium supplement.

[0025] Comparative Example 3 The preparation method of the calcium supplement includes the following steps: S1: Mix 1 g of oat β-glucan and 70 mL of 2 mol / L NaOH aqueous solution, add 1 g of chloroacetic acid, control the temperature at 55 °C, and keep the reaction warm under stirring conditions for 4 h. Then, purify and freeze-dry to obtain carboxymethylated β-glucan; Mix 1 g of sodium alginate and 30 mL of 2 mol / L NaOH aqueous solution, add 0.5 g of chloroacetic acid, control the temperature at 60 °C, and keep the reaction warm under stirring conditions for 3 h. Adjust the pH to neutral with dilute hydrochloric acid, pour the reaction solution into ethanol to precipitate, centrifuge to collect the precipitate, purify by dialysis, and freeze-dry to obtain carboxymethylated sodium alginate; S2: Mix 1 g of carboxymethylated β-glucan and 1 g of carboxymethylated sodium alginate, control the temperature at 35 °C, and keep the reaction warm for 6 h. Add ethanol to terminate the reaction, centrifuge to collect the precipitate, purify by dialysis, and freeze-dry to obtain the polysaccharide material; S3: Mix 2 g of CaCl2 and 150 mL of water, adjust the pH to 7, add 1 g of the polysaccharide material, control the temperature at 55 °C, and keep stirring warm for 3 h. Centrifuge to collect the precipitate, wash with water, purify by dialysis, and freeze-dry to obtain the calcium supplement.

[0026] Comparative Example 4 Compared with Example 4, only the calcium supplement prepared in Example 1 added in Example 4 was replaced with the calcium supplement prepared in Comparative Example 1 in equal amount, and the other components and preparation methods were exactly the same as those in Example 4.

[0027] Comparative Example 5 Compared with Example 4, only the calcium supplement prepared in Example 1 added in Example 4 was replaced with the calcium supplement prepared in Comparative Example 2 in equal amount, and the other components and preparation methods were exactly the same as those in Example 4.

[0028] Comparative Example 6 Compared with Example 4, only the calcium supplement prepared in Example 1 added in Example 4 was replaced with the calcium supplement prepared in Comparative Example 3 in equal amount, and the other components and preparation methods were exactly the same as those in Example 4.

[0029] Performance detection According to the flame atomic absorption spectrometry in "Determination of Calcium in Foods" (GB / T 5009.92-2016), the calcium supplements prepared in Examples 1-3 and Comparative Examples 1-3 were wet digested and the calcium content was determined. The stability of the calcium supplement was expressed by the calcium retention rate. The calculation method of the calcium retention rate is shown in the following formula: Calcium retention rate / % = (calcium content after treatment / calcium content before treatment) × 100% a. Acid-base stability: The calcium supplements prepared in Examples 1-3 and Comparative Examples 1-3 were respectively configured into 2 mg / mL solutions. After sub-packaging, 1 mol / L hydrochloric acid solution and 1 mol / L sodium hydroxide solution were used to adjust the pH of the test tubes to 2, 4, 6, 8, and 10. They were heated in a 37 °C water bath for 2 h, naturally cooled to room temperature, and the free calcium in the samples was removed by dialysis. The calcium content was determined by flame atomic absorption spectrometry, and the calcium retention rate of the samples at different pH values was calculated; the test results are shown in Table 1; Table 1: Statistical table of acid-base stability test data

[0030] As can be seen from Table 1, the calcium supplements prepared in this application have good calcium retention rates under neutral and alkaline conditions. Although the calcium retention rate is low in the acidic environment with a pH of 2, when added as a food additive to solid beverages, the acidity of the solid beverages is low, and excellent stability can be maintained.

[0031] b. Thermal stability: The calcium supplements prepared in Examples 1-3 and Comparative Examples 1-3 were respectively configured into 2 mg / mL solutions. After sub-packaging, they were placed in a water bath at 50, 60, 70, 80, and 90 °C for heating for 30 min, naturally cooled to room temperature, and the free calcium in the samples was removed by dialysis. The calcium content was determined by flame atomic absorption spectrometry, and the calcium retention rate of the samples at different temperatures was calculated; the test results are shown in Table 2; Table 2: Statistical table of thermal stability test data

[0032] As can be seen from Table 2, the calcium supplements prepared in this application have high thermal stability, and during the brewing process of solid beverages, the calcium supplements can stably exist in the beverages.

[0033] c. In vitro simulated gastric digestion: The calcium supplements prepared in Examples 1-3 and Comparative Examples 1-3 were respectively formulated into a 2 mg / mL solution, the pH was adjusted to 2 with 1 mol / L hydrochloric acid solution, 2% (E / S) pepsin was added, and digestion was carried out in a water bath at 37 °C for 2.5 h. Samples were taken every 30 min, and after inactivating the enzyme in a 100 °C water bath, free calcium was removed by dialysis. The calcium content was determined by flame atomic absorption spectrometry, and the calcium retention rate of the sample after gastric digestion was calculated; the test results are shown in Table 3; Table 3: Statistical table of test data for calcium retention rate after gastric digestion

[0034] d. In vitro simulated small intestine digestion: After 2.5 h of gastric digestion, the pH was adjusted to 6.8 with 1 mol / L sodium hydroxide solution, trypsin was added, and digestion was carried out in a water bath at 37 °C for 2.5 h. Samples were taken every 30 min, and after inactivating the enzyme in a 100 °C water bath, free calcium was removed by dialysis. The calcium content was determined by flame atomic absorption spectrometry, and the calcium retention rate of the sample after small intestine digestion was calculated; the test results are shown in Table 4; Table 4: Statistical table of test data for calcium retention rate after small intestine digestion

[0035] As can be seen from Tables 3-4, when the calcium supplement prepared in this application is digested in the human body, it remains stable in the gastrointestinal tract.

[0036] The above has described a specific embodiment of the present invention in detail, but the content described is only a preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the present invention application should still fall within the scope covered by the patent of the present invention.

Claims

1. A preparation method of a milk-based solid beverage, characterized in that, It includes the following steps: blending raw materials in formula amounts to obtain a milk-based solid beverage; the milk-based solid beverage contains 1-7 wt% of a calcium supplement; The preparation method of the calcium supplement includes the following steps: S1: Blend carboxymethylated β-glucan and PBS buffer, add EDC / NHS activator, control the temperature at 25-37 °C and activate for 0.5-1 h under light-shielded conditions to obtain a carboxymethylated β-glucan ester intermediate; Blend carboxymethylated sodium alginate and PBS buffer, add EDC / NHS activator, control the temperature at 25-37 °C and activate for 0.5-1 h under light-shielded conditions to obtain a carboxymethylated sodium alginate ester intermediate; Blend the carboxymethylated β-glucan ester intermediate and the carboxymethylated sodium alginate ester intermediate, control the temperature at 25-40 °C and carry out a heat preservation reaction for 4-8 h, add ethanol to terminate the reaction, centrifuge to collect the precipitate, dialyze and purify, and freeze-dry to obtain a polysaccharide material; S2: Blend CaCl2 and water, adjust the pH to 6.5-7.5, add the polysaccharide material, control the temperature at 50-60 °C and carry out heat preservation stirring for 2-4 h, centrifuge to collect the precipitate, wash with water, dialyze and purify, and freeze-dry to obtain a calcium supplement.

2. The preparation method of a milk-based solid beverage according to claim 1, wherein The EDC / NHS activator is composed of EDC and NHS with a molar ratio of 1:1-2; The addition ratio of carboxymethylated β-glucan, PBS buffer, and EDC / NHS activator is 1 g: 50-100 mL: 0.15-0.45 g; The addition ratio of carboxymethylated sodium alginate, PBS buffer, and EDC / NHS activator is 1 g: 50-100 mL: 0.15-0.45 g; The mass ratio of carboxymethylated β-glucan used in the preparation of the carboxymethylated β-glucan ester intermediate to carboxymethylated sodium alginate used in the carboxymethylated sodium alginate ester intermediate is 1:1-1.

2.

3. The preparation method of a milk-based solid beverage according to claim 1, characterized in that, The addition ratio of CaCl2, water, and polysaccharide material in S2 is 2-5 g: 100-200 mL: 1 g.

4. The preparation method of a milk-based solid beverage according to claim 1, characterized in that, The preparation method of carboxymethylated oat β-glucan includes the following steps: Blend oat β-glucan and NaOH solution, add chloroacetic acid, control the temperature at 50-60 °C and carry out a heat preservation reaction for 3-5 h under stirring conditions, purify and freeze-dry to obtain carboxymethylated β-glucan.

5. The preparation method of a milk-based solid beverage according to claim 4, characterized in that, The NaOH solution is a 2-4 mol / L NaOH aqueous solution; the addition ratio of oat β-glucan, NaOH solution, and chloroacetic acid is 1 g: 50-100 mL: 0.8-1.2 g.

6. The preparation method of a milk-based solid beverage according to claim 1, characterized in that, The preparation method of carboxymethylated sodium alginate includes the following steps: Blend sodium alginate and NaOH solution, add chloroacetic acid, control the temperature at 50-70 °C and carry out a heat preservation reaction for 2-4 h under stirring conditions, adjust the pH to neutral, pour the reaction solution into ethanol for precipitation, centrifuge to collect the precipitate, dialyze and purify, and freeze-dry to obtain carboxymethylated sodium alginate.

7. The preparation method of a milk-based solid beverage according to claim 6, characterized in that, The NaOH solution is a 2-4 mol / L NaOH aqueous solution; the addition ratio of sodium alginate, NaOH solution, and chloroacetic acid is 1 g: 20-40 mL: 0.3-0.8 g.

8. The preparation method of a milk-based solid beverage according to claim 1, characterized in that, The milk-based solid beverage comprises raw materials in the following weight percentages: sweet whey powder 12-15%, milk powder 5-8%, hydrogenated palm kernel oil 30-35%, glucose syrup 42-48%, sodium caseinate 1.5-2.2%, dipotassium hydrogen phosphate 1.3-1.8%, compound emulsifier 1.2-1.9%, calcium supplement 1-7%; the sum of the weight percentages of the raw materials is 100%.

9. The preparation method of a milk-based solid beverage according to claim 8, characterized in that, The compound emulsifier consists of monoglyceride and diglyceride fatty acid ester and diacetyl tartaric acid monoglyceride; the monoglyceride and diglyceride fatty acid ester accounts for 1-1.5% of the total mass of the milk-based solid beverage, and the diacetyl tartaric acid monoglyceride accounts for 0.2-0.4% of the total mass of the milk-based solid beverage; the milk powder is skimmed milk powder.

10. A milk-based solid beverage, characterized in that, It is made by the preparation method described in any one of claims 1-9.

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