Milk for promoting calcium absorption and preparation method therefor

Abstract

The present invention relates to a milk for promoting calcium absorption and a preparation method therefor. The preparation method comprises the following steps: (1) skimming raw milk to obtain skimmed milk and cream; (2) subjecting the skimmed milk obtained in step (1) to membrane processing to obtain membrane-processed milk; (3) mixing the membrane-processed milk obtained in step (2) with the cream obtained in step (1) to obtain fat-reconstituted milk; and (4) mixing sodium hyaluronate with calcium β-hydroxy-β-methylbutyrate to obtain a premix, mixing the premix with the fat-reconstituted milk obtained in step (3), and then performing homogenization and sterilization to obtain a milk for promoting calcium absorption. The preparation method provided in the present invention achieves the technical effects of improving the stability and mouthfeel of milk without adding any food thickeners or edible flavors, and the obtained milk has the functional effects of promoting calcium absorption and improving bone density.

Description

Milk that promotes calcium absorption and its preparation method

[0001] This application claims priority to Chinese invention patent application filed on March 27, 2025, with application number 202510369414.X and invention title "A Milk that Promotes Calcium Absorption and a Method for Preparing the Same". Technical Field

[0002] This invention relates to the field of dairy product technology, and in particular to a type of milk that promotes calcium absorption and its preparation method. Background Technology

[0003] [Corrected according to detailed rule 91, 11.06.2026] The main problems faced by middle-aged and elderly people are as follows: First, the problem of hidden hunger in middle-aged and elderly people: Hidden hunger exists in the 18-59 age group, with 98% of middle-aged and elderly people suffering from severe calcium deficiency, and their daily calcium intake only accounting for 41% of the recommended amount. Second, the problem of muscle loss in middle-aged and elderly people: From about age 40, muscle mass begins to gradually decrease, and between 40 and 70 years old, muscle mass is lost at a rate of about 8% per decade. Therefore, middle-aged and elderly people need to supplement their daily dietary protein intake. Third, the problem of joint degeneration in middle-aged and elderly people: As people enter middle and old age, all tissues and organs in the body will age and degenerate, and joints and bones will also undergo age-related degenerative changes. Fractures and wear and tear on the menisci and soft tissues of joints can also cause premature degeneration and aging.

[0004] Milk and dairy products are rich in calcium with high absorption and utilization rates, making them the best source of dietary calcium. This effectively addresses the problem of insufficient calcium intake in the national diet, promoting bone health. The addition of calcium β-hydroxy-β-methylbutyrate (CaHMB) can help prevent muscle loss and increase muscle protein synthesis. However, this ingredient can cause protein precipitation when combined with protein-containing products.

[0005] CN114568515A discloses a method for preparing a protein solution containing calcium β-hydroxy-β-methylbutyrate. The method involves adjusting the pH of a CaHMB raw material aqueous solution to a weakly acidic level (6.5-7.0) by adding acid-base adjusters (citric acid, malic acid, lactic acid, tartaric acid, ascorbic acid), and then adding protein solution and acid-base adjusters (KOH, KOH, NaOH, sodium bicarbonate) to the above aqueous solution to adjust the pH to 6.7-6.9, thus solving the denaturation problem of CaHMB in the protein solution (reconstituted milk). The addition amount is 1-6%. However, this method requires the use of acid-base additives, which does not conform to the concept of green, low-carbon, and healthy living.

[0006] Therefore, based on the objective nutritional gaps such as insufficient dietary calcium intake and joint and muscle degeneration among middle-aged and elderly people, as well as the subjective needs of middle-aged and elderly consumers, the design and development of high-calcium activity-enhanced milk for middle-aged and elderly people, while avoiding the use of additives, is of practical significance for promoting healthy aging. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a milk (e.g., cow's milk) that promotes calcium absorption and its preparation method. The preparation method provided by this invention achieves the technical effect of improving milk stability and enhancing its taste without the use of any food thickeners or flavorings, and the resulting milk (e.g., cow's milk) also has the functional effects of promoting calcium absorption and improving bone density.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing milk that promotes calcium absorption, the method comprising the following steps:

[0010] (1) Skim the raw milk to obtain skim milk and light cream;

[0011] (2) The skim milk obtained in step (1) is subjected to membrane treatment to obtain membrane-treated milk;

[0012] (3) Mix the membrane-treated milk obtained in step (2) with the light cream obtained in step (1) to obtain fat-refilled milk;

[0013] (4) Sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate are mixed to obtain a premix; the premix is ​​mixed with the fat-refilled milk obtained in step (3), and then homogenized and sterilized to obtain the milk that promotes calcium absorption.

[0014] In some implementations, the milk that promotes calcium absorption is cow's milk that promotes calcium absorption. In some implementations, raw milk is cow's raw milk.

[0015] In existing technologies, achieving naturally high-calcium, naturally high-protein, and bone, muscle, and joint-promoting neutral room-temperature milk products without food additives such as stabilizers, pH adjusters, emulsifiers, or food flavorings presents the following problems:

[0016] First, poor product stability:

[0017] (1) Milk with native protein ≥5.6g / 100mL and native high calcium ≥160mg / 100mL is prone to tube sticking and protein denaturation during ultra-high temperature instantaneous sterilization (UHT sterilization), which affects the product stability within a 6-month shelf life. During storage, fat may float or protein may precipitate, and continuous production and filling may even be impossible.

[0018] (2) The functional ingredient calcium β-hydroxy-β-methylbutyrate (CaHMB) is alkaline, with a pH of 7.2-7.5 in a 1% aqueous solution. It has poor water solubility and poor thermal stability in milk. When added to neutral milk, it causes local protein denaturation when heated, thus affecting the stability of the system during the product's shelf life. This is because CaHMB exists in milk in ionic form and can easily form calcium bridges between protein molecules, leading to protein precipitation.

[0019] Second, the product has a poor taste:

[0020] (1) During the processing of raw high-nutrition milk (raw protein ≥ 5.6g / 100mL, raw high calcium ≥ 160mg / 100mL), fat, protein and lactose molecules will be concentrated, broken and heated, resulting in a rough taste and a bitter taste in the product.

[0021] (2) CaHMB has a bitter taste. Adding it directly to milk will cause an unpleasant flavor and will not be accepted by consumers.

[0022] To address the aforementioned shortcomings, this invention provides a novel method for preparing milk (e.g., cow's milk). From a formulation perspective, this invention introduces sodium hyaluronate and employs a premixing process with CaHMB. Because sodium hyaluronate has a water-retaining effect similar to a thickener, it can improve the water retention of CaHMB. 2+ Ions encapsulate and form a water film, preventing proteins from forming calcium bridges and thus causing protein denaturation. On the other hand, the ion encapsulation effect of sodium hyaluronate on CaHMB alters the triple helix structure of sodium hyaluronate, thereby solving its solubility problem in liquid milk to some extent. In addition, sodium hyaluronate and CaHMB synergistically enhance the effects of promoting calcium absorption and improving bone density function.

[0023] From a technological perspective, this invention adjusts the ratio of β-lactoglobulin and α-lactalbumin in the background of bovine milk through membrane filtration. Macroscopically, this locks in the heat-sensitive protein whey protein in neutral milk, causing the structures of α-lactalbumin and β-lactoglobulin to unfold and decompose into monomers, exposing hydrophobic residues. Finally, a premix of sodium hyaluronate and CaHMB is added, allowing its linear, non-sulfated structure to attach to the hydrophobic residues of the milk proteins, forming a hydrophilic carrier that allows sodium hyaluronate to dissolve in the liquid milk, improving solubility. Simultaneously, this formed hydrophilic carrier effectively prevents denaturation of milk proteins caused by heat processing and encapsulates free calcium ions from CaHMB, thus effectively ensuring thermal stability during subsequent sterilization. The membrane-treated raw milk (e.g., bovine colostrum) forms a stable hydrophilic carrier structure with sodium hyaluronate and CaHMB, while sodium hyaluronate selectively reacts with the CaHMB's calcium ions. 2+This process forms a water film that encapsulates stable, neutral small units, thereby enabling the preparation of room-temperature sodium hyaluronate milk that maintains a good texture within a 6-month shelf life without any thickeners or stabilizers. Furthermore, this milk can remain free from oxidation and non-enzymatic browning under 37°C conditions. In addition, the membrane treatment process employed in this invention, by adjusting the lactose content and combining it with the addition of sodium hyaluronate, can increase the smoothness of the product and eliminate the astringency present in naturally high-nutrient milk.

[0024] Preferably, the materials in step (4) include, by weight, 990-1000 parts of fat-refilled milk (e.g., 990, 992, 994, 996, 998, 1000 parts, etc.), 0.1-2 parts of sodium hyaluronate (e.g., 0.1, 0.2, 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2 parts, etc.), and 0.05-1 part of calcium β-hydroxy-β-methylbutyrate (e.g., 0.05, 0.1, 0.2, 0.5, 0.8, 1 part, etc.).

[0025] Preferably, the molecular weight of the sodium hyaluronate is 80,000-400,000 Da (e.g., 80,000, 100,000, 150,000, 200,000, 250,000, 300,000, 350,000, 400,000 Da, etc.), and more preferably 80,000-200,000 Da.

[0026] In this invention, by adjusting the formulation ratio of fat-refilled milk, sodium hyaluronate, and calcium β-hydroxy-β-methylbutyrate in the raw materials, a better effect can be achieved in improving stability and product taste.

[0027] Preferably, the fat content of the skim milk in step (1) is 0.5-0.8% (e.g., it can be 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, etc.).

[0028] Preferably, in step (2), the protein content in the retentate after membrane treatment is 5.5-6.0% (e.g., 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6.0%, etc.).

[0029] In this invention, when the protein content in the retentate is within the above-mentioned limited range, the ratio of β-lactoglobulin to α-lactalbumin in raw milk (e.g., raw cow's milk) can reach 1.6-3.3. The raw milk (e.g., raw cow's milk) system at this ratio can form a more stable hydrophilic carrier structure with CaHMB and sodium hyaluronate, thereby further improving the stability of the milk.

[0030] Preferably, the membrane treatment in step (2) includes reverse osmosis membrane treatment and ultrafiltration membrane treatment performed sequentially.

[0031] Preferably, the reverse osmosis membrane treatment results in a protein content of 3.6-4.0% in the retentate (e.g., 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, etc.).

[0032] Preferably, the protein content in the retentate after ultrafiltration is 5.5-6.0% (e.g., 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6.0%, etc.).

[0033] In this invention, the lactose content is first adjusted by reversing osmosis (RO) membrane concentration, and then further concentrated by ultrafiltration (UF) membrane to filter out some lactose and sodium. + At the same time, the ratio of β-lactoglobulin and α-lactalbumin in raw milk is adjusted, and sodium hyaluronate, which has properties similar to an emulsifier, is added to increase the smoothness of the product and solve the astringent taste of the original high-nutrient milk.

[0034] Preferably, the fat content in the fat-filled milk in step (3) is 4.0-4.5% (e.g., 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, etc.).

[0035] Preferably, the mixing temperature of the premix in step (4) is 40-65℃ (e.g., 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, etc.), and the mixing speed is ≤1kg / min (e.g., 0.1kg / min, 0.2kg / min, 0.3kg / min, 0.4kg / min, 0.8kg / min, 0.9kg / min, etc.).

[0036] In this invention, under the above-mentioned addition temperature and addition rate, a better material processing effect can be achieved, thereby ensuring the stability and taste of the milk.

[0037] Preferably, the addition of the premix in step (4) includes: mixing the premix with the fat refilled milk obtained in step (3) at a mass ratio of 100-120 times (e.g., 100 times, 105 times, 110 times, 115 times, 120 times, etc.) to form a liquid; and then mixing the liquid with the remaining fat refilled milk in step (3).

[0038] Preferably, the homogenization and sterilization process in step (4) includes a first homogenization process, a pasteurization process, a second homogenization process, and an ultra-high temperature sterilization process performed sequentially.

[0039] Preferably, the temperature of the first homogenization process is 50-80°C (e.g., 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc.), and the pressure is 150-270 bar (e.g., 150 bar, 180 bar, 200 bar, 220 bar, 240 bar, 270 bar, etc.).

[0040] Preferably, the temperature of the second homogenization process is 60-90°C (e.g., 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc.), and the pressure is 220-240 bar (e.g., 220 bar, 225 bar, 230 bar, 235 bar, 240 bar, etc.).

[0041] Preferably, the pasteurization treatment is performed at a temperature of 70-75°C (e.g., 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, etc.) for a time of 10-20 seconds (e.g., 10 seconds, 12 seconds, 14 seconds, 16 seconds, 18 seconds, 20 seconds, etc.).

[0042] Preferably, the ultra-high temperature sterilization treatment is performed at a temperature of 135-140℃ (e.g., 135℃, 136℃, 137℃, 138℃, 139℃, 140℃, etc.) for a time of 4-6s (e.g., 4s, 4.5s, 5s, 5.5s, 6s, etc.).

[0043] Preferably, the preparation method further includes adding a bone health aid.

[0044] Preferably, the amount of the bone health aid added is 0.0012-0.5% of the mass of the fat-refilled milk (e.g., it can be 0.0012%, 0.005%, 0.01%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, etc.).

[0045] Preferably, the bone health supplement comprises any one or a combination of at least two of the following: vitamin D, bovine colostrum basic protein, casein phosphopeptide, milk basic protein, magnesium, phosphorus, chondroitin sulfate, N-acetylglucosamine, glucosamine, or lactase. In this document, magnesium and phosphorus should be understood as various food-acceptable magnesium and phosphorus sources, respectively, which can be used as food fortifiers.

[0046] Preferably, the bone health aid is added after the premix is ​​mixed with the fat-refilled milk in step (4).

[0047] Preferably, the addition is performed at a temperature of 40-50°C (e.g., 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, etc.).

[0048] Step (4) also includes the addition of lactase; after the addition of lactase, there is also an enzymatic hydrolysis process, the temperature of which is 50-60℃ (for example, it can be 50℃, 52℃, 54℃, 56℃, 58℃, 60℃, etc.), and the time of which is 25-35min (for example, it can be 25min, 26min, 28min, 30min, 32min, 34min, 35min, etc.).

[0049] Preferably, the amount of lactase added is 0.001-0.1% of the mass of the fat-refilled milk (e.g., 0.001%, 0.005%, 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, etc.).

[0050] Preferably, the preparation method includes the following steps:

[0051] (1) Skim raw milk (e.g., raw cow's milk) to obtain skim milk and light cream with a fat content of 0.5-0.8% by mass;

[0052] (2) The skim milk obtained in step (1) is subjected to reverse osmosis membrane treatment until the protein content in the retentate is 3.6-4.0%, and then subjected to ultrafiltration membrane treatment until the protein content in the retentate is 5.5-6.0%, to obtain membrane-treated milk;

[0053] (3) Mix the membrane-treated milk obtained in step (2) with the light cream obtained in step (1) to obtain fat-filled milk with a fat content of 4.0-4.5%.

[0054] (4) Sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate are mixed to obtain a premix; the premix is ​​mixed with the fat-refilled milk obtained in step (3) at 40-65℃ and at a speed of ≤1kg / min, and then subjected to a first homogenization treatment at 50-80℃ and 150-270bar, pasteurized at 70-75℃ for 10-20s, subjected to a second homogenization treatment at 60-90℃ and 220-240bar, and subjected to ultra-high temperature sterilization at 135-140℃ for 4-6s to obtain the milk that promotes calcium absorption.

[0055] The materials in step (4) include, by weight, 990-1000 parts of fat-refilled milk, 0.1-2 parts of sodium hyaluronate and 0.05-1 parts of calcium β-hydroxy-β-methylbutyrate.

[0056] Secondly, the present invention provides a calcium-absorption-promoting milk prepared according to the method for preparing calcium-absorption-promoting milk described in the first aspect. In some embodiments, the calcium-absorption-promoting milk is cow's milk that promotes calcium absorption.

[0057] In a third aspect, the present invention provides the use of the calcium-enhancing milk according to the second aspect for non-therapeutic purposes of promoting calcium absorption and / or improving bone density.

[0058] In a fourth aspect, the present invention provides the use of the calcium-enhancing milk according to the second aspect in the preparation of products that promote calcium absorption and / or improve bone density.

[0059] In a fifth aspect, the present invention provides a method for promoting calcium absorption and / or improving bone mineral density in a subject, comprising administering to the subject a milk that promotes calcium absorption as described in the second aspect. In some embodiments, the subject is a mammal, such as a non-human mammal. In some embodiments, the subject is a human.

[0060] Compared with the prior art, the present invention has at least the following beneficial effects:

[0061] The preparation method provided by this invention introduces functional raw materials sodium hyaluronate and CaHMB, and through specific membrane treatment and premixing processes, the resulting milk has a protein content ≥5.0g / 100mL and a native calcium content ≥160mg / 100mL. This achieves the technical effect of improving milk stability and enhancing taste without the use of any food thickeners or flavorings. In addition, the resulting milk also has the functional effects of promoting calcium absorption and improving bone density. Detailed Implementation

[0062] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0063] The sources of materials used in the following embodiments and comparative examples are as follows:

[0064] Raw milk: Meets China's national food safety standard for raw milk, GB 19301;

[0065] Sodium hyaluronate: purity ≥ 95%;

[0066] Bovine colostrum basic protein: manufactured by Keytone Enterprises, New Zealand;

[0067] Casein phosphopeptide: Manufacturer: Shanghai Daoyan Trading Co., Ltd.

[0068] Milk basic protein: manufactured by Xi'an Entaiyuan Biotechnology Co., Ltd.

[0069] Example 1

[0070] This embodiment provides a method for preparing milk that promotes calcium absorption, wherein the raw materials for preparation include, by weight, 999.2 parts of fat-refilled milk, 0.2 parts of sodium hyaluronate (molecular weight 130,000 Da), 0.1 parts of calcium β-hydroxy-β-methylbutyrate, and 0.5 parts of N-acetylglucosamine.

[0071] The preparation method includes the following steps:

[0072] (1) Skim the raw milk to obtain skim milk and light cream with a fat content of 0.7% by mass;

[0073] (2) Skim milk was treated with reverse osmosis membrane until the protein content in the retentate was 3.6%, and then treated with ultrafiltration membrane until the protein content in the retentate was 5.68%, to obtain membrane-treated milk. The ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk was found to be 1.8:1.

[0074] (3) Add light cream to the membrane-treated milk to obtain fat-refilled milk with a fat content of 4.21%;

[0075] (4) Mix sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate to obtain a premix; add the premix to a portion of the fat-refilled milk at 50°C and 0.5 kg / min (the amount is 100 times the total mass of sodium hyaluronate, calcium β-hydroxy-β-methylbutyrate and N-acetylglucosamine), and stir for 10 min to dissolve it; then add N-acetylglucosamine at 40°C and stir for 3 min to dissolve it to obtain a liquid; add the liquid to the remaining fat-refilled milk to complete the mixing.

[0076] (5) The milk that promotes calcium absorption is obtained by first homogenization at 70°C and 200 bar, pasteurization at 72°C for 15 seconds, second homogenization at 80°C and 230 bar, and ultra-high temperature sterilization at 135°C for 6 seconds.

[0077] Example 2

[0078] This embodiment provides a method for preparing milk that promotes calcium absorption, wherein the raw materials for preparation include, by weight: 999.787 parts of fat-refilled milk, 0.125 parts of sodium hyaluronate (molecular weight 154000 Da), 0.050 parts of calcium β-hydroxy-β-methylbutyrate, 0.02 parts of vitamin D, and 0.018 parts of lactase;

[0079] The preparation method includes the following steps:

[0080] (1) Skim the raw milk to obtain skim milk and light cream with a fat content of 0.5% by mass;

[0081] (2) Skim milk was treated with reverse osmosis membrane until the protein content in the retentate was 3.8%, and then treated with ultrafiltration membrane until the protein content in the retentate was 5.95%, resulting in membrane-treated milk. The ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk was found to be 3:1.

[0082] (3) Add light cream to the membrane-treated milk to obtain fat-refilled milk with a fat content of 4% by mass.

[0083] (4) Mix sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate to obtain a premix; add the premix to a portion of the fat-refilled milk at 48°C and 0.3 kg / min (the amount is 100 times the total mass of sodium hyaluronate, calcium β-hydroxy-β-methylbutyrate, and vitamin D, and lactase), and stir for 10 min to dissolve it; then add vitamin D at 45°C and stir for 3 min to dissolve it to obtain a liquid; add the liquid to the remaining fat-refilled milk to complete the mixing.

[0084] (5) The first homogenization treatment was carried out at 50℃ and 150 bar, followed by pasteurization at 70℃ for 20 seconds, then the second homogenization treatment was carried out at 60℃ and 220 bar, and ultra-high temperature sterilization at 136℃ for 5 seconds. Lactase was added to each package in an aseptic online enzyme addition machine, and the package was placed at room temperature (25℃) for 5 days to complete the lactase hydrolysis and obtain the lactose-free milk that promotes calcium absorption.

[0085] Example 3

[0086] This embodiment provides a method for preparing milk that promotes calcium absorption, wherein the raw materials for preparation include, by weight, 996.9 parts of fat-refilled milk, 1 part of sodium hyaluronate (molecular weight 159000 Da), 1 part of calcium β-hydroxy-β-methylbutyrate, 0.1 part of bovine colostrum basic protein, and 1 part of lactase.

[0087] The preparation method includes the following steps:

[0088] (1) Skim the raw milk to obtain skim milk and light cream with a fat content of 0.8% by mass;

[0089] (2) Skim milk was treated with reverse osmosis membrane until the protein content in the retentate was 3.8%, and then treated with ultrafiltration membrane until the protein content in the retentate was 5.89%, resulting in membrane-treated milk. The ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk was found to be 2.3:1.

[0090] (3) Add light cream to the membrane-treated milk to obtain fat-refilled milk with a fat content of 4.43%;

[0091] (4) Sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate are mixed to obtain a premix; the premix is ​​added to a portion of the fat-refilled milk at 55°C and 0.7 kg / min (the amount is 120 times the total mass of sodium hyaluronate, calcium β-hydroxy-β-methylbutyrate, bovine colostrum basic protein and lactase), and stirred for 10 min to dissolve it; then bovine colostrum basic protein is added at 40°C and stirred for 5 min to dissolve it to obtain a liquid; the liquid is added to the remaining fat-refilled milk to complete the mixing.

[0092] (5) The milk was homogenized at 80°C and 270 bar, pasteurized at 72°C for 10 seconds, lactase was added, and the milk was hydrolyzed at 57°C for 30 minutes. Then, the milk was homogenized at 80°C and 240 bar, and ultra-high temperature sterilized at 139°C for 4 seconds to obtain the lactose-free milk that promotes calcium absorption.

[0093] Example 4

[0094] This embodiment provides a method for preparing milk that promotes calcium absorption, wherein the raw materials for preparation include, by weight, 997.8 parts of fat-refilled milk, 2 parts of sodium hyaluronate (molecular weight 80000 Da) and 0.2 parts of calcium β-hydroxy-β-methylbutyrate;

[0095] The preparation method includes the following steps:

[0096] (1) Skim the raw milk to obtain skim milk and light cream with a fat content of 0.7% by mass;

[0097] (2) Skim milk was treated with reverse osmosis membrane until the protein content in the retentate was 4%, and then treated with ultrafiltration membrane until the protein content in the retentate was 6%, resulting in membrane-treated milk. The ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk was found to be 3.3:1.

[0098] (3) Add light cream to the membrane-treated milk to obtain fat-refilled milk with a fat content of 4.5%;

[0099] (4) Mix sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate to obtain a premix; add the premix to a portion of the fat-refilled milk at 60℃ and 1kg / min (the amount is 100 times the mass of sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate), stir for 10min to dissolve it, and obtain a liquid; add the liquid to the remaining fat-refilled milk to complete the mixing.

[0100] (5) The milk that promotes calcium absorption is obtained by first homogenization at 70°C and 200 bar, pasteurization at 72°C for 15 seconds, second homogenization at 90°C and 230 bar, and ultra-high temperature sterilization at 138°C for 6 seconds.

[0101] Example 5

[0102] This embodiment provides a method for preparing milk that promotes calcium absorption, wherein the raw materials for preparation include, by weight: 997.988 parts of fat-refilled milk, 1.5 parts of sodium hyaluronate (molecular weight 400,000 Da), 0.5 parts of calcium β-hydroxy-β-methylbutyrate, and 0.012 parts of casein phosphopeptide.

[0103] The preparation method includes the following steps:

[0104] (1) Skim the raw milk to obtain skim milk and light cream with a fat content of 0.6% by mass;

[0105] (2) Skim milk was treated with reverse osmosis membrane until the protein content in the retentate was 4%, and then treated with ultrafiltration membrane until the protein content in the retentate was 5.98%, resulting in membrane-treated milk. The ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk was found to be 3.1:1.

[0106] (3) Add light cream to the membrane-treated milk to obtain fat-refilled milk with a fat content of 4.16%;

[0107] (4) Mix sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate to obtain a premix; add the premix to a portion of the fat-refilled milk at 45°C and 0.5 kg / min (the amount is 120 times the total mass of sodium hyaluronate, calcium β-hydroxy-β-methylbutyrate, and casein phosphopeptide), and stir for 10 min to dissolve it; then add casein phosphopeptide at 40°C and stir for 5 min to dissolve it to obtain a liquid; add the liquid to the remaining fat-refilled milk to complete the mixing.

[0108] (5) The milk that promotes calcium absorption is obtained by first homogenization at 70°C and 200 bar, pasteurization at 72°C for 15 s, second homogenization at 80°C and 230 bar, and ultra-high temperature sterilization at 137°C for 4 s.

[0109] Example 6

[0110] This embodiment provides a method for preparing milk that promotes calcium absorption, wherein the raw materials for preparation include, by weight, 993.08 parts of fat-refilled milk, 1.8 parts of sodium hyaluronate (200,000 Da), 0.1 parts of calcium β-hydroxy-β-methylbutyrate, 5 parts of milk basic protein, and 0.02 parts of lactase;

[0111] The preparation method includes the following steps:

[0112] (1) Skim the raw milk to obtain skim milk and light cream with a fat content of 0.7% by mass;

[0113] (2) Skim milk was treated with reverse osmosis membrane until the protein content in the retentate was 3.5%, and then treated with ultrafiltration membrane until the protein content in the retentate was 5.5%, to obtain membrane-treated milk. The ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk was found to be 1.6:1.

[0114] (3) Add light cream to the membrane-treated milk to obtain fat-refilled milk with a fat content of 4.15%;

[0115] (4) Mix sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate to obtain a premix; add the premix to a portion of the fat-refilled milk at 50°C and 0.5 kg / min (the amount is 100 times the total mass of sodium hyaluronate, calcium β-hydroxy-β-methylbutyrate, milk basic protein and lactase), and stir for 10 min to dissolve it; then add milk basic protein at 45°C and stir for 3 min to dissolve it to obtain a liquid; add the liquid to the remaining fat-refilled milk to complete the mixing.

[0116] (5) The milk is homogenized at 50°C and 150 bar, pasteurized at 70°C for 20 seconds, lactase is added, and the milk is hydrolyzed at 50°C for 35 minutes. Then, the milk is homogenized at 60°C and 220 bar, and ultra-high temperature sterilized at 137°C for 4 seconds to obtain the milk that promotes calcium absorption.

[0117] Example 7

[0118] This embodiment provides a method for preparing milk that promotes calcium absorption. The only difference between this embodiment and Example 1 is that the raw materials used in this embodiment contain 0.05 parts sodium hyaluronate and 1.2 parts calcium β-hydroxy-β-methylbutyrate. The other ingredients are the same as in Example 1.

[0119] Example 8

[0120] This embodiment provides a method for preparing milk that promotes calcium absorption. The only difference between this method and Example 1 is that the raw materials used in this method are sodium hyaluronate (2.2 parts) and calcium β-hydroxy-β-methylbutyrate (0.03 parts), while the other components are the same as in Example 1.

[0121] Example 9

[0122] This embodiment provides a method for preparing milk that promotes calcium absorption. The only difference between this embodiment and Example 1 is that in step (2), the milk is treated with an ultrafiltration membrane until the protein content in the retentate is 5.3%, and membrane-treated milk is obtained. The ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk is 1.4:1. Other steps are the same as in Example 1.

[0123] Example 10

[0124] This embodiment provides a method for preparing milk that promotes calcium absorption. The only difference between this embodiment and Example 1 is that in step (2), the milk is treated with an ultrafiltration membrane until the protein content in the retentate is 6.5%, and membrane-treated milk is obtained. The ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk is 3.5:1. Other steps are the same as in Example 1.

[0125] Comparative Example 1

[0126] This comparative example provides a method for preparing milk that promotes calcium absorption. The only difference between this method and Example 1 is that sodium hyaluronate is not added; otherwise, the method is the same as in Example 1.

[0127] The results showed that the direct addition of calcium β-hydroxy-β-methylbutyrate in step (4) caused denaturation of some milk proteins. After ultra-high temperature sterilization in step (5), the tubes became sticky and the product had particulate sediment, making it impossible to conduct sensory testing and product function verification.

[0128] Comparative Example 2

[0129] This comparative example provides a method for preparing milk that promotes calcium absorption. The only difference between this method and Example 1 is that step (4) does not involve the preparation of premixed materials. Instead, sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate are added sequentially to the fat-refilled milk. The rest is the same as in Example 1.

[0130] The results showed that after the product was filled and left at room temperature for 3 days, protein precipitation was found at the bottom of the package when it was cut open, making it impossible to carry out subsequent evaluation and verification.

[0131] Comparative Example 3

[0132] This comparative example provides a method for preparing milk that promotes calcium absorption. The only difference between this method and Example 1 is that steps (1)-(3) are omitted, and in step (4), fat-filled milk is replaced with an equal amount of raw milk (the ratio of β-lactoglobulin to α-lactalbumin in the raw milk is 1.2:1). Otherwise, the method is the same as in Example 1.

[0133] The results showed that the direct addition of calcium β-hydroxy-β-methylbutyrate in step (4) caused denaturation of some milk proteins, which resulted in scaling during ultra-high temperature sterilization in step (5), making it impossible to fill the product and to conduct subsequent product evaluation and verification.

[0134] Test case

[0135] Quality control indicators:

[0136] (1) Stability indicators (lower limit indicators): Clarity index ≤ 0.030, particle size median diameter ≤ 0.30 μm, centrifugal sedimentation rate ≤ 2.5%.

[0137] (2) Stability indicators for a 6-month shelf life:

[0138] Δ Clarification Index (samples stored at room temperature for 6 months - samples removed from production line, absolute value) ≤ 0.1;

[0139] Δparticle size median (samples stored at room temperature for 6 months - samples taken after production, absolute value) ≤ 0.1 μm;

[0140] ΔCentrifugation sedimentation rate (samples stored at room temperature for 6 months - samples taken after discharge, absolute value) ≤ 1.0%.

[0141] (3) Microbiology: Commercially sterile.

[0142] (4) Sensory evaluation: Sensory score ≥ 85 points.

[0143] (5) Bone density function evaluation: If the bone calcium content or bone density is significantly higher than that of the low calcium control group and not lower than that of the corresponding dose of calcium carbonate control group, and the calcium absorption rate is not lower than that of the calcium carbonate control group, it can be determined that the test sample has the effect of helping to improve bone density.

[0144] Test method:

[0145] (1) Clarity index: tested using a LUMiSizer X65 stability analyzer, with a light factor of 1.00, a rotation speed of 4000 rpm, a temperature of 25℃, a profile of 300, and a time interval of 10s.

[0146] (2) Particle size analysis: median diameter (μm): The median diameter was obtained by using an LA 960 laser particle size analyzer with a transmittance of 70-90%.

[0147] (3) Centrifugation sedimentation rate (%): Weigh 50g of sample and place it in a centrifuge tube. Centrifuge at 3500rpm for 15min. Place the centrifuge tube with the supernatant removed in a 37℃ oven to dry for 2min. Calculate the sedimentation amount xg. Centrifugation sedimentation rate = (x / 50)*100%.

[0148] (4) Microbial determination (commercial sterility): Take one sample from each batch and store it in a refrigerator at 2-5℃ as a control. After the remaining samples are kept at 36℃±1℃ for 10 days, perform sensory, pH, and smear staining microscopic examination. If there are no signs of microbial growth, it is determined to be commercial sterility. For the test method, please refer to GB 4789.26.

[0149] (5) α-lactalbumin content: Refer to T / CSIQ 77001-2020 Determination of α-lactalbumin content in dairy products - High performance liquid chromatography;

[0150] β-lactoglobulin content: Refer to NY / T 1663-2008 Determination of β-lactoglobulin in milk and dairy products - Polyacrylamide gel electrophoresis.

[0151] (6) Sensory evaluation: Organize personnel (n=30 people) who have received professional sensory training, are in good health and have no lactose intolerance, and have a habit of drinking milk to conduct sensory evaluation of commercially sterile products. The full score is 100 points. The evaluation criteria are shown in Table 1. The final score is the average value.

[0152] Table 1

[0153] (7) Bone density function evaluation method: Refer to "Methods for Functional Testing and Evaluation of Health Foods (2023)".

[0154] Test results:

[0155] The sensory evaluation results of each embodiment and comparative example are shown in Table 2.

[0156] Table 2

[0157] The bone mineral density results for each embodiment and comparative example are shown in Table 3.

[0158] Table 3

[0159] The calcium absorption rate results of each embodiment and comparative example for promoting calcium absorption are shown in Table 4.

[0160] Table 4

[0161] The results of the enhanced immune function evaluation of each embodiment and comparative example are shown in Table 5.

[0162] Table 5

[0163] The test results and stability data are summarized in Table 6.

[0164] Table 6

[0165] The test results show that:

[0166] (1) As can be seen from Examples 1 to 10, the present invention adjusts the content ratio of β-lactoglobulin and α-lactalbumin in raw milk through membrane treatment process, and solves the problem of milk denaturation and bitter taste caused by CaHMB due to alkalinity by introducing sodium hyaluronate and combining it with premixing process. It effectively achieves the preparation of milk with good stability, good taste and function of promoting calcium absorption and improving bone density.

[0167] (2) By comparing Example 1 and Examples 7-10, it can be seen that the present invention, through further optimization of product formula and adoption of membrane treatment process, has the technical effect of further improving product stability within a shelf life of 6 months at room temperature, such as no precipitation, no protein denaturation, and uniform tissue state, and good taste without astringency or blandness. At the same time, sodium hyaluronate: N-acetylglucosamine = 2:5 can significantly promote calcium absorption.

[0168] (3) By comparing Example 1 and Comparative Example 1, it can be seen that when hyaluronic acid is not added, the stability of the obtained milk decreases. Even if the ratio of milk α-lactalbumin and β-lactoglobulin is adjusted, the problem of denaturation of β-hydroxy-β-methylbutyrate calcium in milk protein system cannot be solved. After ultra-high temperature sterilization, the tubes become sticky and the product has particulate sediment.

[0169] A comparison of Example 1 and Comparative Example 2 shows that without premixing, the resulting milk exhibits protein precipitation after 3 days at room temperature, resulting in poor shelf-life stability and failing to guarantee product stability for a 6-month shelf life. A comparison of Example 1 and Comparative Example 3 shows that without membrane treatment of raw milk, the stability of the resulting milk decreases: the functional ingredients sodium hyaluronate, N-acetylglucosamine, and calcium β-hydroxy-β-methylbutyrate react with proteins in a flocculation reaction, causing protein denaturation and product instability. This leads to scaling and tube clogging during the ultra-high temperature sterilization stage, making product filling impossible.

[0170] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing milk that promotes calcium absorption, characterized in that, The preparation method includes the following steps: (1) Skim the raw milk to obtain skim milk and light cream; (2) The skim milk obtained in step (1) is subjected to membrane treatment to obtain membrane-treated milk; (3) Mix the membrane-treated milk obtained in step (2) with the light cream obtained in step (1) to obtain fat-refilled milk; (4) Sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate are mixed to obtain a premix; the premix is ​​mixed with the fat-refilled milk obtained in step (3), and then homogenized and sterilized to obtain the milk that promotes calcium absorption.

2. The preparation method according to claim 1, characterized in that, The milk that promotes calcium absorption is cow's milk, and the raw milk is raw cow's milk.

3. The preparation method according to claim 1 or 2, characterized in that, The materials in step (4) include, by weight, 990-1000 parts of fat-refilled milk, 0.1-2 parts of sodium hyaluronate and 0.05-1 parts of calcium β-hydroxy-β-methylbutyrate.

4. The preparation method according to any one of claims 1-3, characterized in that, The fat content of the skim milk in step (1) is 0.5-0.8% by mass; In step (2), the membrane treatment is carried out until the protein content in the retentate is 5.5-6.0%.

5. The preparation method according to any one of claims 1-4, characterized in that, The membrane treatment in step (2) includes reverse osmosis membrane treatment and ultrafiltration membrane treatment performed sequentially; The reverse osmosis membrane treatment results in a protein content of 3.6-4.0% in the retentate; the ultrafiltration membrane treatment results in a protein content of 5.5-6.0% in the retentate.

6. The preparation method according to any one of claims 1-5, characterized in that, The fat content in the fat-refilled milk described in step (3) is 4.0-4.5%.

7. The preparation method according to any one of claims 1-6, characterized in that, The mixing temperature of the premixed material in step (4) is 40-65℃, and the mixing speed is ≤1kg / min; The homogenization and sterilization processes in step (4) include a first homogenization process, a pasteurization process, a second homogenization process, and an ultra-high temperature sterilization process performed sequentially. Optionally, the temperature of the first homogenization process is 50-80°C and the pressure is 150-270 bar; Optionally, the temperature of the second homogenization process is 60-90°C and the pressure is 220-240 bar; Optionally, the pasteurization treatment is performed at a temperature of 70-75°C for a time of 10-20 seconds. Optionally, the ultra-high temperature sterilization process is carried out at a temperature of 135-140°C for 4-6 seconds.

8. The preparation method according to any one of claims 1-7, characterized in that, The preparation method also includes adding bone health aids; Optionally, the bone health aid includes any one or a combination of at least two of the following: vitamin D, bovine colostrum basic protein, casein phosphopeptide, milk basic protein, magnesium, phosphorus, chondroitin sulfate, N-acetylglucosamine, glucosamine, or lactase. Optionally, the bone health aid is added after the premix is ​​mixed with the fat-refilled milk in step (4), and the addition is carried out at a temperature of 40-50°C.

9. The preparation method according to any one of claims 1-8, characterized in that, Step (4) also includes the step of adding lactase; after adding lactase, there is also an enzymatic hydrolysis process, the temperature of which is 50-60℃ and the time of which is 25-35min.

10. The preparation method according to any one of claims 1-9, characterized in that, The preparation method includes the following steps: (1) Skim the raw milk to obtain skim milk and light cream with a fat content of 0.5-0.8% by mass; (2) The skim milk obtained in step (1) is subjected to reverse osmosis membrane treatment until the protein content in the retentate is 3.6-4.0%, and then subjected to ultrafiltration membrane treatment until the protein content in the retentate is 5.5-6.0%, to obtain membrane-treated milk; (3) Mix the membrane-treated milk obtained in step (2) with the light cream obtained in step (1) to obtain fat-filled milk with a fat content of 4.0-4.5%. (4) Sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate are mixed to obtain a premix; the premix is ​​mixed with the fat-refilled milk obtained in step (3) at 40-65℃ and at a speed of ≤1kg / min, and then subjected to a first homogenization treatment at 50-80℃ and 150-270bar, pasteurized at 70-75℃ for 10-20s, subjected to a second homogenization treatment at 60-90℃ and 220-240bar, and subjected to ultra-high temperature sterilization at 135-140℃ for 4-6s to obtain the milk that promotes calcium absorption; The materials in step (4) include, by weight, 990-1000 parts of fat-refilled milk, 0.1-2 parts of sodium hyaluronate and 0.05-1 parts of calcium β-hydroxy-β-methylbutyrate.

11. A milk that promotes calcium absorption, prepared by a method according to any one of claims 1-10.

12. The milk that promotes calcium absorption according to claim 11, characterized in that, The milk that promotes calcium absorption is cow's milk.

13. The use of the calcium-enhancing milk according to claim 11 or 12 for non-therapeutic purposes of promoting calcium absorption and / or improving bone density.

14. Use of the calcium-absorbing milk according to claim 11 or 12 in the preparation of products that promote calcium absorption and / or improve bone density.

15. A method for promoting calcium absorption and / or improving bone density in subjects, comprising administering to subjects a milk that promotes calcium absorption as described in claim 11 or 12.

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