A kind of milk for promoting calcium absorption and its preparation method

Abstract

The present invention relates to a milk for promoting calcium absorption and a preparation method thereof. The preparation method comprises the following steps: (1) degreasing raw milk to obtain skimmed milk and cream; (2) subjecting the skimmed milk obtained in step (1) to membrane treatment to obtain membrane-treated milk; (3) mixing the membrane-treated milk obtained in step (2) with the cream obtained in step (1) to obtain fat-backfilled milk; (4) mixing sodium hyaluronate and β-hydroxy-β-methylbutyric acid calcium to obtain a premix; mixing the premix with the fat-backfilled milk obtained in step (3), and then performing homogenization treatment and sterilization treatment to obtain the milk for promoting calcium absorption. The preparation method provided by the present invention achieves the technical effects of improving the stability of milk and enhancing the taste without any food thickeners and edible flavors, and the obtained milk simultaneously has the functional effects of promoting calcium absorption and improving bone density.

Description

Technical Field

[0001] The invention relates to the technical field of dairy products, and in particular to milk for promoting calcium absorption and a preparation method thereof. Background Art

[0002] With the intensification of aging, the nutritional bottleneck of exclusive food for the middle-aged and elderly people needs to be solved urgently. The middle-aged and elderly people mainly have the following problems: First, the hidden hunger problem of the middle-aged and elderly: There is hidden hunger in the 18-59 age group, among which 98% of the middle-aged and elderly people are seriously deficient in calcium, and the daily calcium intake accounts for only 41% of the recommended amount. Second, the problem of muscle loss in the middle-aged and elderly: From about the age of 40, the muscle mass of the human body begins to gradually decrease. Between the ages of 40 and 70, the muscle mass is lost at a rate of about 8% every decade. Therefore, the daily dietary protein intake of Chinese elderly people needs to be supplemented. Third, the problem of joint degeneration in the middle-aged and elderly: After entering middle age, all tissues and organs of the body will age and degenerate, and the joints of bones and tissues will also undergo senile degenerative changes. If fractures occur and the meniscus and soft tissues of the joints are worn, it will also cause premature degeneration and aging.

[0003] Milk and dairy products are rich in calcium and have a high absorption rate. They are the best source of dietary calcium and can effectively solve the problem of insufficient dietary calcium intake in the country and promote bone health. At the same time, the addition of calcium β-hydroxy-β-methylbutyrate (CaHMB) can prevent muscle loss and increase muscle protein synthesis. However, when this raw material is combined with protein-containing products, protein precipitation will occur.

[0004] CN114568515A discloses a method for preparing a protein solution containing calcium β-hydroxy-β-methylbutyrate, wherein the pH of the CaHMB raw material aqueous solution is adjusted to a weak acidity (6.5-7.0) by adding an acid-base regulator (citric acid, malic acid, lactic acid, tartaric acid, ascorbic acid), and then the protein solution + acid-base regulator (KOH, KOH, NaOH, sodium bicarbonate) are added to the aqueous solution to adjust the pH to 6.7-6.9, thereby solving the denaturation problem of CaHMB in the protein solution (reconstituted milk), and 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 life.

[0005] Therefore, based on the objective nutritional gaps such as insufficient dietary calcium intake and joint and muscle degeneration among the middle-aged and elderly people, as well as the subjective needs of middle-aged and elderly consumers, the design and development of native high-calcium activity-fortified milk for middle-aged and elderly people, while avoiding the use of additives, has practical significance for promoting healthy aging. Summary of the invention

[0006] To solve the above technical problems, the present invention provides a milk for promoting calcium absorption and a preparation method thereof. The preparation method provided by the present invention achieves the technical effects of improving the stability of milk and enhancing the taste without any food thickeners or edible flavors, and the obtained milk simultaneously has the functional effects of promoting calcium absorption and improving bone density.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a preparation method of a milk for promoting calcium absorption, and the preparation method includes the following steps:

[0009] (1) Degrease raw milk to obtain skim milk and cream;

[0010] (2) Perform membrane treatment on the skim milk obtained in step (1) to obtain membrane-treated milk;

[0011] (3) Mix the membrane-treated milk obtained in step (2) with the cream obtained in step (1) to obtain fat-backfilled milk;

[0012] (4) Mix sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate to obtain a premix; mix the premix with the fat-backfilled milk obtained in step (3), and then perform homogenization treatment and sterilization treatment to obtain the milk for promoting calcium absorption.

[0013] In the prior art, under the condition of no food additives such as stabilizers, acid-base regulators, emulsifiers or edible flavors, there are the following problems in achieving a neutral normal-temperature milk product with native high calcium, native high-index protein, and promoting bone, muscle and joint health:

[0014] First, the product stability is poor:

[0015] (1) When the native protein in milk ≥ 5.6 g / 100 mL and native high calcium ≥ 160 mg / 100 mL are subjected to ultra-high temperature instantaneous sterilization (UHT sterilization), it is easy to cause tube fouling and protein denaturation, which affects the product stability within a 6-month shelf life. During storage, fat floating or protein precipitation will occur, and even continuous production and filling cannot be completed.

[0016] (2) The functional ingredient calcium β-hydroxy-β-methylbutyrate (CaHMB) is alkaline, and the pH of its 1% aqueous solution is 7.2 - 7.5. Its water solubility and thermal stability in milk are poor. When added to neutral milk, local protein denaturation will occur when heated, thus affecting the system stability within the product shelf life. The reason is that CaHMB exists in milk in an ionic form and is very easy to form calcium bridges between protein molecules, resulting in protein precipitation.

[0017] Second, the product taste is poor:

[0018] (1) In the processing of raw high-nutrition milk (raw protein ≥ 5.6 g / 100 mL, raw high calcium ≥ 160 mg / 100 mL), the fat, protein, and lactose molecules will be concentrated, broken, and heated, resulting in a rough taste and astringency in the product.

[0019] (2) CaHMB has a bitter taste, and directly adding it to milk will cause bad flavor and is not acceptable to consumers.

[0020] Based on the above defects, the present invention provides a brand-new method for preparing milk. From the aspect of the formula, the present invention introduces sodium hyaluronate and adopts a process of premixing with CaHMB. Since sodium hyaluronate has a water-retaining effect similar to that of a thickener, it can wrap the Ca 2+ ions to form a water film, preventing proteins from forming calcium bridges with calcium, thereby causing protein denaturation; on the other hand, the ion-wrapping effect of sodium hyaluronate on CaHMB will change the triple helix structure of sodium hyaluronate, thus solving its dissolution problem in liquid milk to a certain extent; in addition, sodium hyaluronate also synergistically improves the effects of promoting calcium absorption and improving bone density with CaHMB.

[0021] From the aspect of the process, the present invention adjusts the content ratio of β-lactoglobulin and α-lactalbumin in the milk background through a membrane filtration treatment process. Macroscopically, it locks the heat-sensitive protein whey protein in neutral milk. The structures of α-lactalbumin and β-lactoglobulin unfold and decompose into monomers, exposing hydrophobic residues. Finally, a premix of sodium hyaluronate and CaHMB is added, and its linear non-sulfated structure attaches to the hydrophobic residues of milk proteins, forming a hydrophilic carrier to dissolve sodium hyaluronate in liquid milk and improve solubility; at the same time, the formed hydrophilic carrier can effectively avoid the denaturation of milk proteins caused by heat treatment and wrap the free calcium ions of CaHMB, thereby effectively ensuring the thermal stability during subsequent sterilization. The bovine colostrum after membrane treatment forms a stable hydrophilic carrier structure together with sodium hyaluronate and CaHMB. At the same time, sodium hyaluronate can selectively combine with the Ca 2+ of CaHMB to form a water film to wrap the stable neutral small units, thereby realizing the preparation of room-temperature sodium hyaluronate milk with a good tissue state within a shelf life of 6 months without any thickeners or stabilizers, and the milk can maintain the effects of no oxidation and non-enzymatic browning under the condition of being kept at 37°C. In addition, the membrane treatment process adopted by the present invention adjusts the lactose content, and combined with the addition of sodium hyaluronate, it can increase the smooth taste of the product and solve the astringency problem existing in raw high-nutrition milk.

[0022] Preferably, the materials in step (4) include, by weight: 1000 parts of fat-backfilled milk, 0.1 - 0.2 parts of sodium hyaluronate (such as 0.1 part, 0.2 part, etc.), and 0.05 - 1 part of calcium β-hydroxy-β-methylbutyrate (such as 0.05 part, 0.1 part, 0.2 part, 0.5 part, 0.8 part, 1 part, etc.).

[0023] Preferably, the molecular weight of the sodium hyaluronate is 80000 - 400000 Da (such as 80000, 100000, 150000, 200000, 250000, 300000, 350000, 400000 Da, etc.), and preferably 80000 - 200000 Da.

[0024] In the present invention, by the formulation ratios of fat-backfilled milk, sodium hyaluronate, and calcium β-hydroxy-β-methylbutyrate in the preparation raw materials, better effects of enhancing stability and product taste can be achieved.

[0025] Preferably, the fat mass content of the skim milk in step (1) is 0.5 - 0.8% (such as 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, etc.).

[0026] Preferably, the protein mass content in the retentate after the membrane treatment in step (2) is 5.5 - 6.0% (such as 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6.0%, etc.).

[0027] In the present invention, when the protein content in the retentate is within the above-defined range, the ratio of β-lactoglobulin to α-lactalbumin in raw milk can reach 1.6 - 3.3. The raw milk system at this ratio can form a more stable hydrophilic carrier structure with CaHMB and sodium hyaluronate, thereby further enhancing the stability of milk.

[0028] Preferably, the membrane treatment in step (2) includes reverse osmosis membrane treatment and ultrafiltration membrane treatment carried out in sequence.

[0029] Preferably, the protein mass content in the retentate after the reverse osmosis membrane treatment is 3.6 - 4.0% (such as 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, etc.).

[0030] Preferably, the protein mass content in the retentate after the ultrafiltration membrane treatment is 5.5 - 6.0% (such as 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6.0%, etc.).

[0031] In the present invention, the lactose content is first adjusted by reverse osmosis (RO) membrane concentration and then concentrated by ultrafiltration (UF) membrane to filter out part of the lactose and Na + , and at the same time, the ratio of β-lactoglobulin to α-lactalbumin in raw milk is adjusted. On this basis, sodium hyaluronate with properties similar to those of an emulsifier is added, which can enhance the smooth taste of the product and solve the astringency problem existing in the original high-nutrition milk.

[0032] Preferably, the fat content in the fat-backfilled milk in step (3) is 4.0 - 4.5% (e.g., it can be 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, etc.).

[0033] Preferably, the mixing temperature of the premix in step (4) is 40 - 65°C (e.g., it can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, etc.), and the mixing speed ≤ 1 kg / min (e.g., it can be 0.1 kg / min, 0.2 kg / min, 0.3 kg / min, 0.4 kg / min, 0.8 kg / min, 0.9 kg / min, etc.).

[0034] In the present invention, under the above-mentioned addition temperature and addition speed, a better material mixing effect can be achieved, thereby ensuring the stability and taste of the milk.

[0035] Preferably, the addition of the premix in step (4) includes: mixing the premix with the fat-backfilled milk obtained in step (3) at a mass ratio of 100 - 120 times (e.g., it can be 100 times, 105 times, 110 times, 115 times, 120 times, etc.) to form a liquid mixture; then mixing the liquid mixture with the remaining fat-backfilled milk in step (3).

[0036] Preferably, the homogenization treatment and sterilization treatment in step (4) include a first homogenization treatment, pasteurization treatment, second homogenization treatment, and ultra-high temperature sterilization treatment carried out in sequence.

[0037] Preferably, the temperature of the first homogenization treatment is 50 - 80°C (e.g., it can be 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc.), and the pressure is 150 - 270 bar (e.g., it can be 150 bar, 180 bar, 200 bar, 220 bar, 240 bar, 270 bar, etc.).

[0038] Preferably, the temperature of the second homogenization treatment is 60 - 90°C (e.g., it can be 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, etc.), and the pressure is 220 - 240 bar (e.g., it can be 220 bar, 225 bar, 230 bar, 235 bar, 240 bar, etc.).

[0039] Preferably, the temperature of the pasteurization treatment is 70 - 75 °C (such as 70 °C, 71 °C, 72 °C, 73 °C, 74 °C, 75 °C, etc.), and the time is 10 - 20 s (such as 10 s, 12 s, 14 s, 16 s, 18 s, 20 s, etc.).

[0040] Preferably, the temperature of the ultra-high temperature sterilization treatment is 135 - 140 °C (such as 135 °C, 136 °C, 137 °C, 138 °C, 139 °C, 140 °C, etc.), and the time is 4 - 6 s (such as 4 s, 4.5 s, 5 s, 5.5 s, 6 s, etc.).

[0041] Preferably, the preparation method further includes adding a bone health aid.

[0042] Preferably, the bone health aid includes any one or a combination of at least two of vitamin D, bovine colostrum basic protein, casein phosphopeptide, milk basic protein, magnesium, phosphorus, N-acetylglucosamine, or lactase.

[0043] Preferably, the bone health aid is added after the premix in step (4) is mixed with the fat-backfilled milk.

[0044] Preferably, the addition is carried out at a temperature of 40 - 50 °C (such as 40 °C, 42 °C, 44 °C, 46 °C, 48 °C, 50 °C, etc.).

[0045] Step (4) further includes a step of adding lactase; after adding lactase, an enzymatic hydrolysis process is further included. The temperature of the enzymatic hydrolysis is 50 - 60 °C (such as 50 °C, 52 °C, 54 °C, 56 °C, 58 °C, 60 °C, etc.), and the time of the enzymatic hydrolysis is 25 - 35 min (such as 25 min, 26 min, 28 min, 30 min, 32 min, 34 min, 35 min, etc.).

[0046] Preferably, the addition amount of the lactase is 0.001 - 0.1% of the mass of the fat-backfilled milk (such as 0.001%, 0.005%, 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, etc.).

[0047] Preferably, the preparation method includes the following steps:

[0048] (1) Skim the raw milk to obtain skim milk and cream with a fat mass content of 0.5 - 0.8%.

[0049] (2) Subject the skim milk obtained in step (1) to reverse osmosis membrane treatment until the protein mass content in the retentate is 3.6 - 4.0%, and then subject it to ultrafiltration membrane treatment until the protein mass content in the retentate is 5.5 - 6.0% to obtain membrane-treated milk;

[0050] (3) Mix the membrane-treated milk obtained in step (2) with the light cream obtained in step (1) to obtain fat-backfilled milk with a fat mass content of 4.0 - 4.5%;

[0051] (4) Mix sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate to obtain a premix; mix the premix with the fat-backfilled milk obtained in step (3) at 40 - 65°C at a rate of ≤1 kg / min, then conduct the first homogenization treatment at 50 - 80°C and 150 - 270 bar, conduct pasteurization treatment at 70 - 75°C for 10 - 20 s, conduct the second homogenization treatment at 60 - 90°C and 220 - 240 bar, and conduct ultra-high temperature sterilization treatment at 135 - 140°C for 4 - 6 s to obtain the milk for promoting calcium absorption.

[0052] In step (4), each material is included by weight parts: 1000 parts of fat-backfilled milk, 0.1 - 0.2 parts of sodium hyaluronate, and 0.05 - 1 part of calcium β-hydroxy-β-methylbutyrate.

[0053] In the second aspect, the present invention provides a milk for promoting calcium absorption prepared by the preparation method of the milk for promoting calcium absorption according to the first aspect.

[0054] Compared with the prior art, the present invention has at least the following beneficial effects:

[0055] The preparation method provided by the present invention introduces functional raw materials sodium hyaluronate and CaHMB, and through specific membrane treatment and premixing processes, the obtained milk has a protein content ≥5.0 g / 100mL and a native calcium content ≥160 mg / 100 mL, achieving the technical effects of improving the stability of milk and enhancing the taste without any food thickeners and edible flavors, and the obtained milk simultaneously has the functional effects of promoting calcium absorption and improving bone density. Specific Embodiments

[0056] To facilitate the understanding of the present invention, the following examples are listed. Those skilled in the art should understand that the examples are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0057] The sources of materials used in the following examples and comparative examples are as follows:

[0058] Raw cow milk: Conforms to GB 19301;

[0059] Sodium hyaluronate: Purity ≥95%;

[0060] Colostrum basic protein: The manufacturer is Keytone Enterprises in New Zealand;

[0061] Casein phosphopeptide: The manufacturer is Shanghai Daoyan Trading Co., Ltd.;

[0062] Milk basic protein: The manufacturer is Xi'an Entaiyuan Biotechnology Co., Ltd.

[0063] Example 1

[0064] This example provides a method for preparing calcium-absorbing milk, and the preparation raw materials include, by weight: 999.2 parts of fat-backfilled milk, 0.2 parts of sodium hyaluronate (molecular weight 130,000 Da), 0.1 part of calcium β-hydroxy-β-methylbutyrate, and 0.5 part of N-acetylglucosamine;

[0065] The preparation method includes the following steps:

[0066] (1) Skim the raw milk to obtain skim milk with a fat mass content of 0.7% and cream;

[0067] (2) Treat the skim milk with a reverse osmosis membrane until the protein mass content in the retentate is 3.6%, and then treat it with an ultrafiltration membrane until the protein mass content in the retentate is 5.68% to obtain membrane-treated milk. It is detected that the content ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk is 1.8:1;

[0068] (3) Add cream to the membrane-treated milk to obtain fat-backfilled milk with a fat mass content of 4.21%;

[0069] (4) Mix sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate to obtain a premix; add the premix to part of the fat-backfilled milk at 50°C and 0.5 kg / min (the dosage 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 feed liquid; add the feed liquid to the remaining fat-backfilled milk to complete the mixing;

[0070] (5) Perform the first homogenization treatment at 70°C and 200 bar, perform pasteurization treatment at 72°C for 15 s, perform the second homogenization treatment at 80°C and 230 bar, and perform ultra-high temperature sterilization treatment at 135°C for 6 s to obtain the calcium-absorbing milk.

[0071] Example 7

[0072] This embodiment provides a method for preparing milk that promotes calcium absorption. The only difference from Embodiment 1 is that in the preparation raw materials, the content of sodium hyaluronate is 0.05 parts and the content of calcium β-hydroxy-β-methylbutyrate is 1.2 parts. For the rest, refer to Embodiment 1.

[0073] Embodiment 9

[0074] This embodiment provides a method for preparing milk that promotes calcium absorption. The only difference from Embodiment 1 is that in step (2), the ultrafiltration membrane is processed until the protein mass content in the retentate is 5.3%, obtaining membrane-treated milk. It is detected that the content ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk is 1.4:1. For the rest, refer to Embodiment 1.

[0075] Embodiment 10

[0076] This embodiment provides a method for preparing milk that promotes calcium absorption. The only difference from Embodiment 1 is that in step (2), the ultrafiltration membrane is processed until the protein mass content in the retentate is 6.5%, obtaining membrane-treated milk. It is detected that the content ratio of β-lactoglobulin to α-lactalbumin in the membrane-treated milk is 3.5:1. For the rest, refer to Embodiment 1.

[0077] Comparative Example 1

[0078] This comparative example provides a method for preparing milk that promotes calcium absorption. The only difference from Embodiment 1 is that sodium hyaluronate is not added. For the rest, refer to Embodiment 1.

[0079] The results show that directly adding calcium β-hydroxy-β-methylbutyrate in step (4) causes partial denaturation of some milk proteins, and after ultra-high temperature sterilization in step (5), the pipe gets blocked, and there are particle precipitates in the product, making it impossible to carry out sensory tests and product function verification.

[0080] Comparative Example 2

[0081] This comparative example provides a method for preparing milk that promotes calcium absorption. The only difference from Embodiment 1 is that in step (4), the preparation of the premix is not carried out, and sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate are directly added to the fat-backfilled milk in sequence. For the rest, refer to Embodiment 1.

[0082] The results show that after the product is filled and stored at room temperature for 3 days and then the package is cut open, protein precipitates appear at the bottom, making it impossible to carry out subsequent evaluation and verification.

[0083] Comparative Example 3

[0084] This comparative example provides a method for preparing milk that promotes calcium absorption. The difference from Example 1 is only that steps (1)-(3) are not carried out, and in step (4), the fat-backfilled milk is replaced with an equal amount of raw cow milk (the content ratio of β-lactoglobulin to α-lactalbumin in the raw cow milk is 1.2:1), and the rest refers to Example 1.

[0085] The results showed that directly adding calcium β-hydroxy-β-methylbutyrate in step (4) caused partial denaturation of some milk proteins, and scaling occurred during the ultra-high temperature sterilization in step (5), making it impossible to fill the product and impossible to verify the subsequent evaluation of the product.

[0086] Test Example

[0087] Quality control indicators:

[0088] (1) Stability indicators (lower limit indicators): clarification index ≤ 0.030, median particle size ≤ 0.30 μm, centrifugal sedimentation rate ≤ 2.5%.

[0089] (2) Stability indicators for a 6-month shelf life:

[0090] Δ clarification index (sample placed at room temperature for 6 months - lower limit sample, absolute value) ≤ 0.1;

[0091] Δ median particle size (sample placed at room temperature for 6 months - lower limit sample, absolute value) ≤ 0.1 μm;

[0092] Δ centrifugal sedimentation rate (sample placed at room temperature for 6 months - lower limit sample, absolute value) ≤ 1.0%.

[0093] (3) Microorganisms: commercially sterile.

[0094] (4) Sensory evaluation: sensory score ≥ 85 points.

[0095] (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 calcium carbonate control group at the corresponding dose, 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.

[0096] Test methods:

[0097] (1) Clarification index: Test using a LUMiSizer X65 stability analyzer, with a light factor of 1.00, a rotation speed of 4000 rpm, a temperature of 25 °C, a profile line of 300, and a time interval of 10 s.

[0098] (2) Median particle size in particle size analysis (μm): Test using a LA 960 laser particle size analyzer, with a light transmittance of 70 - 90%, to obtain the D50 median particle size index.

[0099] (3) Centrifugal precipitation rate (%): Weigh 50 g of the sample and place it in a centrifuge tube. Use a centrifuge to centrifuge at a speed of 3500 rpm for 15 minutes. Place the centrifuge tube with the supernatant removed in an incubator at 37°C and dry it for 2 minutes. Calculate the precipitation amount as x g. The centrifugal precipitation rate = (x / 50) * 100%.

[0100] (4) Determination of microorganisms (commercial sterility): Take 1 sample from each batch and store it in a refrigerator at 2 - 5°C as a control. After incubating the remaining samples at 36°C ± 1°C for 10 days, conduct sensory evaluation, pH measurement, smear staining and microscopic examination. If there is no sign of microbial proliferation, it is determined to be commercially sterile. For the detection method, please refer to GB 4789.26.

[0101] (5) α-Lactalbumin content: Refer to T / CSIQ 77001-2020 Determination of α-Lactalbumin Content in Dairy Products - High Performance Liquid Chromatography Method;

[0102] β-Lactoglobulin content: Refer to NY / T 1663-2008 Determination of β-Lactoglobulin in Milk and Dairy Products - Polyacrylamide Gel Electrophoresis Method.

[0103] (6) Sensory evaluation: Organize personnel (n = 30 people) who have received professional sensory training, are in good health and have no lactose intolerance, and usually have the habit of drinking milk to conduct sensory evaluation on the products that have reached commercial sterility. The full score is 100 points. The evaluation criteria are shown in Table 1, and the final score result is the average value.

[0104] Table 1

[0105]

[0106] (7) Bone density function evaluation method: Refer to "Functional Test and Evaluation Method of Health Food (2023)".

[0107] Test results:

[0108] The sensory evaluation results of each example and comparative example are shown in Table 2.

[0109] Table 2

[0110]

[0111] The bone density index results of each example and comparative example are shown in Table 3.

[0112] Table 3

[0113]

[0114] The calcium absorption rate results of promoting calcium absorption of each example and comparative example are shown in Table 4.

[0115] Table 4

[0116]

[0117] The evaluation results of the enhanced immune function of each example and comparative example are shown in Table 5 as follows.

[0118] Table 5

[0119]

[0120] Summarize the above test results and stability data, as shown in Table 6.

[0121] Table 6

[0122]

[0123] It can be seen from the test results that:

[0124] (1) It can be seen from Examples 1, 7, 9 - 10 that the present invention adjusts the content ratio of β - lactoglobulin and α - lactalbumin in raw milk through a membrane treatment process, and through the process of introducing sodium hyaluronate and combining premixing, synergistically solves the problems that CaHMB causes milk denaturation due to alkalinity and has a bitter taste and poor taste, effectively realizes the preparation of milk with good stability, good taste, and functions of promoting calcium absorption and improving bone density.

[0125] (2) It can be seen from the comparison of Examples 1, 7, 9 - 10 that the present invention further optimizes the product formula and adopts a membrane treatment process, which has further improved product stability such as no precipitation, no protein denaturation, and uniform tissue state within a 6 - month shelf life at room temperature, good taste without astringency or tastelessness, and at the same time, the technical effect that sodium hyaluronate:N - acetylglucosamine = 2:5 can significantly promote calcium absorption.

[0126] (3) It can be seen from the comparison of Example 1 and Comparative Example 1 that when no sodium hyaluronate is added, the stability of the obtained milk decreases, and even if the ratio of α - lactalbumin and β - lactoglobulin in the milk is adjusted, the problem of denaturation of calcium β - hydroxy - β - methylbutyrate in the milk protein system cannot be solved, and pipe clogging occurs after ultra - high temperature sterilization, and the product has particle precipitation;

[0127] It can be seen from the comparison of Example 1 and Comparative Example 2 that when the premixing process is not adopted, the obtained milk undergoes protein precipitation after being placed at room temperature for 3 days, and the shelf - life stability is poor, and it is impossible to ensure the stability of the product with a 6 - month shelf life.

[0128] From the comparison between Example 1 and Comparative Example 3, it can be seen that when raw milk is not subjected to membrane treatment, the stability of the obtained milk decreases: the functional ingredients sodium hyaluronate, N-acetylglucosamine, and calcium β-hydroxy-β-methylbutyrate react with proteins to cause flocculation reactions, resulting in protein denaturation, causing instability in the product system, scaling and tube fouling during the ultra-high temperature sterilization stage, and the product cannot be filled.

[0129] The applicant declares that the above description is only the specific implementation manner 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 thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A preparation method of milk for promoting calcium absorption, characterized in that, The preparation method comprises the following steps: (1) Degreasing raw milk to obtain skimmed milk and cream; (2) subjecting the skimmed milk obtained in step (1) to membrane treatment to obtain membrane-treated milk; the membrane treatment is performed until the protein content in the retentate is 5.5-6.0% by mass; (3) mixing the membrane-treated milk obtained in step (2) with the cream obtained in step (1) to obtain fat-filled milk; (4) Mixing sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate to obtain a premix; mixing the premix with the fat-filled milk obtained in step (3), and then homogenizing and sterilizing to obtain the milk for promoting calcium absorption; the materials include, by weight: 1000 parts of fat-filled milk, 0.1-0.2 parts of sodium hyaluronate, and 0.05-1 parts of calcium β-hydroxy-β-methylbutyrate.

2. The preparation method according to claim 1, characterized in that, The fat content of the skimmed milk in step (1) is 0.5-0.8%.

3. The preparation method according to claim 1, wherein, The membrane treatment in step (2) includes reverse osmosis membrane treatment and ultrafiltration membrane treatment performed sequentially; The reverse osmosis membrane is used to treat the retentate until the protein content is 3.6-4.0% by mass; the ultrafiltration membrane is used to treat the retentate until the protein content is 5.5-6.0% by mass.

4. The preparation method according to claim 1, wherein The fat content of the fat backfilled milk in step (3) is 4.0-4.5%.

5. The preparation method according to claim 1, characterized in that, The mixing temperature of the premix in step (4) is 40-65°C, and the mixing speed is ≤1 kg / min; The homogenization and sterilization treatments in step (4) include a first homogenization treatment, a pasteurization treatment, a second homogenization treatment, and an ultra-high temperature sterilization treatment performed in sequence; The temperature of the first homogenization treatment is 50-80°C and the pressure is 150-270 bar; The temperature of the second homogenization treatment is 60-90°C and the pressure is 220-240 bar; The pasteurization treatment is performed at a temperature of 70-75°C and a time of 10-20 seconds; The ultra-high temperature sterilization treatment is carried out at a temperature of 135-140° C. and a time of 4-6 s.

6. The preparation method according to claim 1, wherein The preparation method further comprises adding a bone health aid; The bone health aid comprises any one or a combination of at least two of vitamin D, bovine colostrum alkaline protein, casein phosphopeptide, milk alkaline protein, magnesium, phosphorus, N-acetylglucosamine or lactase; The bone health enhancer is added after the premix is mixed with the fat backfill milk in step (4), and the addition is carried out at a temperature of 40-50°C.

7. The preparation method according to claim 1, characterized in that, Step (4) further comprises the step of adding lactase; after the addition of lactase, an enzymolysis process is also included, wherein the enzymolysis temperature is 50-60° C. and the enzymolysis time is 25-35 min.

8. The preparation method according to claim 1, wherein The preparation method comprises the following steps: (1) skimming raw milk to obtain skimmed milk and cream with a fat content of 0.5-0.8% by mass; (2) treating the skimmed milk obtained in step (1) with a reverse osmosis membrane until the protein content in the retentate is 3.6-4.0% by mass, and then treating the skimmed milk with an ultrafiltration membrane until the protein content in the retentate is 5.5-6.0% by mass, thereby obtaining membrane-treated milk; (3) Mix the membrane-treated milk obtained in step (2) with the light cream obtained in step (1) to obtain fat-backfilled milk with a fat mass content of 4.0 - 4.5%; (4) Mix sodium hyaluronate and calcium β-hydroxy-β-methylbutyrate to obtain a premix; mix the premix with the fat-backfilled milk obtained in step (3) at 40 - 65 °C at a rate of ≤1 kg / min, then perform the first homogenization treatment at 50 - 80 °C and 150 - 270 bar, perform pasteurization treatment at 70 - 75 °C for 10 - 20 s, perform the second homogenization treatment at 60 - 90 °C and 220 - 240 bar, and perform ultra-high temperature sterilization treatment at 135 - 140 °C for 4 - 6 s to obtain the milk that promotes calcium absorption; In step (4), each material is included by weight parts: 1000 parts of fat-backfilled milk, 0.1 - 0.2 parts of sodium hyaluronate, and 0.05 - 1 part of calcium β-hydroxy-β-methylbutyrate.

9. A milk that promotes calcium absorption prepared by the preparation method of the milk that promotes calcium absorption according to any one of claims 1 - 8.

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