Formula and preparation method of yak milk powder with high nutritional value

Abstract

The invention relates to the technical field of dairy product processing, and discloses a formula of yak milk powder with high nutritional value and a preparation method of the yak milk powder. Comprising 92 to 95 parts of a yak milk solid matter, 3 to 5 parts of whey protein powder, 1 to 2 parts of fructo-oligosaccharide, 0.3 to 0.6 part of a composite vitamin mineral substance, 0.05 to 0.2 part of a lactase microcapsule, 0.05 to 0.2 part of a seabuckthorn flavone extract, 0.3 to 0.8 part of a yak milk fat globule membrane, 0.1 to 0.3 part of a conjugated linoleic acid concentrate and 0.1 to 0.3 part of an emulsifier. A multi-dimensional health gain system for brain, intestine and immune functions is formed by the yak milk fat globule membrane, the sea-buckthorn flavone, the highland barley beta-glucan and the conjugated linoleic acid, the yak milk fat globule membrane promotes brain nerve development of infants, the sea-buckthorn flavone and the conjugated linoleic acid synergistically resist oxidation, the highland barley beta-glucan enhances the intestinal barrier function, and the brain, intestine and immune functions are enhanced. Nutrition and function synergism is achieved, and the limitation of single nutrition supplement of traditional milk powder is broken through.

Description

Technical Field

[0001] The present invention relates to the technical field of dairy product processing, and specifically provides a formula for high-nutrition-value yak milk powder and a preparation method thereof. Background Art

[0002] The unique yak milk resources on the Qinghai-Tibet Plateau have natural high-nutrition characteristics due to the unique plateau ecological environment. The milk naturally contains active ingredients such as immunoglobulins, lactoferrin, and conjugated linoleic acid. The protein and calcium contents are significantly higher than those of ordinary cow milk, providing a high-quality raw material basis for the development of high-nutrition-value dairy products. With the in-depth research of modern nutrition, the "three highs" characteristics of yak milk (high concentration, high specific gravity, and high active ingredients) have been gradually recognized. The balanced ratio of amino acids, vitamins, and trace elements meets the nutritional needs of the human body. At the same time, the demand for functional dairy products in the consumer market continues to grow, especially the demand for products with characteristics such as enhancing immunity, promoting bone health, and improving metabolic function has increased significantly.

[0003] However, in the current technology, the nutritional functions of the yak milk powder formula are too single. The formula design mainly focuses on the supplementation of basic nutrients, lacking the synergistic enhancement of multiple systems such as the brain, intestine, and immunity, resulting in the problem that the product function is limited to the basic nutrition supplementation level. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a formula for high-nutrition-value yak milk powder and a preparation method thereof, which solves the problem that the nutritional functions are too single, resulting in the product function being limited to the basic nutrition supplementation level.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A formula for high-nutrition-value yak milk powder includes: 92 - 95 parts of yak milk solids, 3 - 5 parts of whey protein powder, 1 - 2 parts of fructooligosaccharide, 0.3 - 0.6 parts of compound vitamins and minerals, 0.05 - 0.2 parts of lactase microcapsules, 0.05 - 0.2 parts of seabuckthorn flavonoid extract, 0.3 - 0.8 parts of yak milk fat globule membrane, 0.1 - 0.3 parts of conjugated linoleic acid concentrate, and 0.1 - 0.3 parts of emulsifier;

[0006] The yak milk solids are derived from the raw milk of yaks in pastures on the Qinghai-Tibet Plateau, with a fat content ≥ 6% and a protein content ≥ 5%. The content of immunoglobulin IgG in the milk powder is ≥ 2mg / g, and the content of lactoferrin is ≥ 80mg / 100g;

[0007] The compound vitamins and minerals include vitamin D3, vitamin K2-MK7, calcium, and iron.

[0008] Preferably, the lactase microcapsules include:

[0009] Inner layer, a complex of yak whey protein and lactase, where the proportion of lactoferrin is ≥ 10%;

[0010] Middle layer, sodium alginate, and the cross-linking agent is a composite solution of calcium chloride and calcium lactate;

[0011] Outer layer, a mixture of yak casein micelles and hulless barley β-glucan, with the purity of β-glucan ≥ 80%;

[0012] The activity of the lactase is ≥ 6000 ALU / g.

[0013] Preferably, the yak milk fat globule membrane is extracted from raw yak milk by low-temperature centrifugation separation technology, and the content of sphingomyelin is ≥ 15%.

[0014] Preferably, the conjugated linoleic acid concentrate is obtained by supercritical CO 2 extracting yak milk fat, and the proportion of the conjugated linoleic acid concentrate in the total fatty acids is ≥ 1.5%.

[0015] A method for preparing high-nutrition-value yak milk powder, the method comprising the following steps:

[0016] S1. Raw material pretreatment: After filtering the raw yak milk from the Qinghai-Tibet Plateau at 4°C, centrifugally degreasing to adjust the fat content to 4% - 6%, and extracting the yak milk fat globule membrane from the degreased raw milk by centrifugal separation;

[0017] S2. Preparation of lactase microcapsules: Mix lactase with yak whey protein solution, let it stand and cross-link at 4°C to form the inner layer. Then spray the sodium alginate solution onto the surface of the inner layer, immerse it in the composite solution of calcium chloride and calcium lactate for cross-linking to form the middle layer. Finally, coat the outer layer with a mixture of yak casein micelles and hulless barley β-glucan by fluidized bed spraying technology;

[0018] S3. Mixing and homogenization: Mix yak milk solids, whey protein powder, fructooligosaccharide, compound vitamin and mineral, seabuckthorn flavonoid extract, and conjugated linoleic acid concentrate, add them to the yak milk fat globule membrane, and perform two-stage homogenization treatment to obtain yak milk nutrient mixture;

[0019] S4. Sterilization and concentration: Sterilize the yak milk nutrient mixture by ultra-high pressure sterilization process, and then concentrate it in a vacuum concentration device to a solid content of 45% - 50%, with the evaporation temperature less than 60 degrees Celsius;

[0020] S5. Drying and granulation: After low-temperature spray drying, granulate it by fluidized bed agglomeration to obtain yak milk powder, where the particle size is 80 - 200 μm and the dissolution time is ≤ 15 seconds.

[0021] Preferably, in S1, the centrifugal separation controls the centrifugal temperature to be less than 10°C, the rotation speed is controlled at 8000 - 10000 rpm, and the retention rate of sphingomyelin is ≥90%.

[0022] Preferably, in S2, the concentration of the calcium chloride and calcium lactate composite solution is 0.5 mol / L, and the molar ratio is 1:2;

[0023] The mass ratio of the yak casein micelles to the hulless barley β-glucan mixture is 3:1, and the purity of β-glucan is ≥80%.

[0024] Preferably, in S3, the first-stage homogenization pressure for the two-stage homogenization treatment is 15 - 20 MPa, and the second-stage homogenization pressure is 5 - 8 MPa.

[0025] Preferably, in S4, the pressure for ultra-high pressure sterilization is controlled at 500 - 600 MPa, the time is 3 - 5 minutes, and the retention rate of immunoglobulin activity is ≥90%.

[0026] The present invention provides a formula for high-nutrition-value yak milk powder and its preparation method. It has the following beneficial effects:

[0027] 1. The present invention forms a multi-dimensional health enhancement system for brain, intestine and immune functions by combining yak milk fat globule membrane, seabuckthorn flavonoids, hulless barley β-glucan and conjugated linoleic acid. Among them, the yak milk fat globule membrane promotes the brain nerve development of infants and young children, seabuckthorn flavonoids and conjugated linoleic acid have synergistic antioxidant effects, and hulless barley β-glucan enhances the intestinal barrier function, realizing the enhancement of nutrition and function, and breaking through the limitation of single-nutrition supplementation of traditional milk powder.

[0028] 2. In the present invention, the lactase microcapsule is composed of an inner layer of yak whey protein, a middle layer of sodium alginate, an outer layer of yak casein micelles and hulless barley β-glucan, which can accurately target release and efficiently protect lactase, ensure that lactase plays a role in the most suitable environment, decompose lactose into glucose and galactose, and help lactose-intolerant people digest the lactose in the milk powder, expanding the applicable population of the product.

[0029] 3. The present invention combines low-temperature centrifugal separation and ultra-high pressure sterilization, so that the retention rates of sphingomyelin and immunoglobulin in the yak milk fat globule membrane are ≥90%, and with low-temperature concentration and spray drying, the oxidation rates of conjugated linoleic acid and seabuckthorn flavonoids are ≤3%, ensuring high nutritional density and high biological activity of the milk powder, enhancing the resistance of people with low immunity, and assisting people with metabolic regulation needs to maintain metabolic balance. Description of the Drawings

[0030] Figure 1 It is a flow chart of a preparation method of a high-nutrition-value yak milk powder of the present invention. Detailed Embodiments

[0031] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings of the present invention. 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.

[0032] Please refer to the attached Figure 1 , the embodiment of the present invention provides a formula for high-nutrition-value yak milk powder, including: 92-95 parts of yak milk solids, 3-5 parts of whey protein powder, 1-2 parts of fructooligosaccharide, 0.3-0.6 parts of compound vitamins and minerals, 0.05-0.2 parts of lactase microcapsules, 0.05-0.2 parts of seabuckthorn flavonoid extract, 0.3-0.8 parts of yak milk fat globule membrane, 0.1-0.3 parts of conjugated linoleic acid concentrate, and 0.1-0.3 parts of emulsifier;

[0033] The yak milk solids are derived from the raw milk of yaks in pastures on the Qinghai-Tibet Plateau, with a fat content of ≥6%, a protein content of ≥5%, and the content of immunoglobulin IgG in the milk powder of ≥2mg / g and the content of lactoferrin of ≥80mg / 100g;

[0034] The compound vitamins and minerals include vitamin D3, vitamin K2-MK7, calcium, and iron.

[0035] Specifically, yak milk solids: Yak milk solids are the core base material of the formula, derived from the raw milk of yaks in pollution-free pastures on the Qinghai-Tibet Plateau, with a natural fat content of ≥6% and a protein content of ≥5%, and rich in minerals such as calcium, iron, and zinc, as well as natural immunoglobulin (IgG) and lactoferrin, providing high-density nutritional support, optimizing the amino acid composition of proteins, and enhancing the nutritional value and physiological functions of the milk powder;

[0036] Whey protein powder: As a high-quality protein supplement, it adjusts the ratio of casein to whey protein in yak milk to 60:40, which is more easily digested and absorbed. It is rich in essential amino acids (such as leucine and isoleucine), promotes muscle synthesis and repair, and at the same time improves the solubility of the milk powder. Its synergistic effect with yak milk protein can reduce the risk of allergy;

[0037] Fructooligosaccharide: It is a kind of water-soluble dietary fiber, which selectively promotes the proliferation of intestinal Bifidobacterium and Lactobacillus as a prebiotic, inhibits the colonization of pathogenic bacteria, and can significantly improve the balance of intestinal flora, relieve constipation, and enhance the absorption rate of minerals such as calcium and magnesium when ingested 1.5g per day;

[0038] Compound vitamins and minerals: Vitamin D3 (150-250IU / 100g) can promote intestinal calcium absorption, maintain calcium homeostasis in the blood, and prevent rickets and osteoporosis;

[0039] Vitamin K2-MK7 (30 - 80 μg / 100 g) can activate osteocalcin, guide calcium deposition in bones rather than blood vessels, and reduce the risk of arterial calcification;

[0040] Calcium (600 - 1000 mg / 100 g) is added in the form of calcium phosphate to strengthen bone and dental health;

[0041] Iron (5 - 10 mg / 100 g), in the form of heme iron, has a bioavailability 3 times higher than that of non-heme iron, to prevent iron-deficiency anemia;

[0042] Lactase microcapsules: Designed for lactose-intolerant people, they achieve targeted release through a three-layer embedding structure, that is, the enzyme activity retention is ≥90% in the gastric acid environment with pH 2.0, and lactase (activity ≥6000 ALU / g) is released in the intestinal fluid with pH 6.8 in the intestine for activation, and then lactose is decomposed into glucose and galactose to eliminate abdominal distension and diarrhea symptoms, enabling lactose-intolerant people to drink safely and improving the tolerance of the milk powder;

[0043] Seabuckthorn flavonoid extract: Extracted from seabuckthorn fruits on the Qinghai-Tibet Plateau, with a total flavonoid content ≥30%, it has strong antioxidant activity, can scavenge free radicals, reduce the expression of inflammatory factors (such as IL-6, TNF-α), enhance immunity. Clinical studies have shown that daily intake of 50 mg of seabuckthorn flavonoids can reduce the frequency of colds by 30%, and at the same time improve cardiovascular function, reduce blood lipid and blood pressure, inhibit platelet aggregation, and prevent the occurrence of cardiovascular diseases;

[0044] Yak milk fat globule membrane: Isolated from yak milk by low-temperature centrifugation technology, it is rich in sphingomyelin, glycoprotein and sialic acid. Among them, sphingomyelin is a key component of neuron myelin sheath, which helps to promote the formation and development of nerve synapses, improve nerve conduction speed, enhance memory and cognitive ability, thus promoting the brain development of infants and young children. At the same time, it enhances the intestinal barrier function and reduces the incidence of diarrhea;

[0045] Conjugated linoleic acid concentrate: It reduces fat storage by inhibiting the activity of lipoprotein lipase and activates peroxisome proliferator-activated receptor, promotes fat decomposition, can promote fat oxidation and decomposition, reduce fat accumulation, helps to control weight. In addition, it can also enhance immunity, regulate the immune system function, and help the body resist diseases;

[0046] Emulsifier; Achieves uniform dispersion by reducing the surface tension of fat globules, repairs the cell membrane structure, improves the reconstitutability of the milk powder (solubility ≥98%), avoids the phenomenon of fat floating or stratification, ensures good stability of the milk powder during reconstitution, makes the reconstituted milk liquid have a uniform texture and delicate taste, and at the same time enhances the absorption efficiency of fat-soluble nutrients;

[0047] The emulsifier includes soy lecithin or sunflower lecithin, with a particle size ≤ 50 μm, and the solubility of the milk powder ≥ 98%.

[0048] Specifically, the emulsifier is selected from soy lecithin or sunflower lecithin (with a particle size ≤ 50 μm). Through the amphiphilicity (hydrophilic head and hydrophobic tail) of phospholipid molecules, it reduces the surface tension of fat globules, enabling the high content of natural fat in yak milk powder to be evenly dispersed in the aqueous phase, avoiding fat floating or caking, thereby improving the dispersibility. At the same time, the phosphatidylcholine component of lecithin can repair the intestinal mucosal cell membrane structure, improve the bioavailability of fat-soluble nutrients (such as compound vitamin minerals and conjugated linoleic acid concentrate), and endow the milk powder with a delicate taste.

[0049] The lactase microcapsule includes:

[0050] The inner layer is a complex of yak whey protein and lactase, in which the proportion of lactoferrin ≥ 10%;

[0051] The middle layer is sodium alginate, and the cross-linking agent is a composite solution of calcium chloride and calcium lactate;

[0052] The outer layer is a mixture of yak casein micelles and hulless barley β-glucan, with the purity of β-glucan ≥ 80%;

[0053] The lactase activity ≥ 6000 ALU / g.

[0054] Specifically, for the inner layer protection: Yak whey protein binds with lactase to form a complex, in which the proportion of lactoferrin ≥ 10%. Utilizing the acid resistance and antibacterial properties of lactoferrin, a rigid protective layer is formed in the gastric acid environment, reducing the denaturation of enzyme proteins and simultaneously inhibiting the proliferation of gastric pathogens;

[0055] For the middle layer controlled release: Sodium alginate is cross-linked by a composite solution of calcium chloride - calcium lactate to form a pH-responsive gel network. It maintains the structural compactness under gastric acid conditions. After entering the intestine (pH > 6), due to the dissolution of calcium lactate and the protonation of the carboxyl group of sodium alginate, the network expands and ruptures, achieving the precise enteric release of lactase;

[0056] For the outer layer function enhancement: Yak casein micelles and hulless barley β-glucan are combined through hydrophobic interaction and hydrogen bonding to form a physical barrier against mechanical shear and enzymatic hydrolysis. Hulless barley β-glucan, as a prebiotic, synergistically promotes the proliferation of Bifidobacterium with lactase, improves the dispersion stability of the microcapsule in the milk powder system, and at the same time, the β-glucan on the outer layer of the lactase microcapsule and seabuckthorn flavonoids in the milk powder can synergistically inhibit intestinal inflammation.

[0057] The yak milk fat globule membrane is extracted from raw yak milk by low-temperature centrifugation separation technology, and the content of sphingomyelin ≥ 15%.

[0058] Specifically, as one of the important phospholipids that make up biological membranes, sphingomyelin works synergistically with other abundant phospholipids, glycoproteins, gangliosides and other bioactive substances, which helps to promote the formation and orderly development of a large number of neural synapses, can also effectively increase the nerve conduction speed, and significantly improve memory and cognitive ability.

[0059] The conjugated linoleic acid concentrate is obtained by supercritical CO 2 extraction of yak milk fat, and the proportion of conjugated linoleic acid concentrate in total fatty acids is ≥1.5%.

[0060] Specifically, the conjugated linoleic acid concentrate obtained by supercritical CO 2 extraction of yak milk fat can, at the level of fat metabolism, enhance the activity of lipoxidase, accelerate fat decomposition, convert it into energy for the body to consume, and at the same time inhibit the function of fat synthase to prevent the accumulation of new fat, helping to achieve healthy fat loss. In terms of the immune system, conjugated linoleic acid can regulate the activity of immune cells such as T lymphocytes and B lymphocytes, enhance the body's resistance to pathogens, and reduce the risk of infection.

[0061] A preparation method of high-nutrition-value yak milk powder, the method comprising the following steps:

[0062] S1. Raw material pretreatment: After filtering the raw yak milk from the Qinghai-Tibet Plateau at 4°C, centrifugally degrease it to adjust the fat content to 4% - 6%, and extract yak milk fat globule membrane from the degreased raw milk by centrifugal separation;

[0063] S2. Preparation of lactase microcapsules: Mix lactase with yak whey protein solution, let it stand and crosslink at 4°C to form the inner layer, then spray the sodium alginate solution onto the surface of the inner layer, immerse it in a composite solution of calcium chloride and calcium lactate for crosslinking to form the middle layer, and finally coat the outer layer with a mixture of yak casein micelles and hulless barley β-glucan by fluidized bed spraying technology;

[0064] S3. Mixing and homogenization: Mix yak milk solids, whey protein powder, fructooligosaccharide, compound vitamin and mineral, seabuckthorn flavonoid extract, and conjugated linoleic acid concentrate, add them to the yak milk fat globule membrane for two-stage homogenization treatment to obtain yak milk nutrient mixture;

[0065] S4. Sterilization and concentration: Sterilize the yak milk nutrient mixture by ultra-high pressure sterilization process, and then concentrate it in a vacuum concentration device to a solid content of 45% - 50%, with the evaporation temperature less than 60°C;

[0066] S5. Drying and granulation: After low-temperature spray drying, granulate it by fluidized bed agglomeration to obtain yak milk powder, where the particle size is 80 - 200 μm and the dissolution time is ≤15 seconds.

[0067] Specifically, in S1, the raw milk of Qinghai-Tibet Plateau yaks is filtered at low temperature. The low-temperature environment can inhibit the growth and reproduction of microorganisms, and filtration is carried out to intercept impurities in the raw milk, achieving the preliminary purification of the raw milk. Then, centrifugal defatting operation is performed. While removing part of the fat, the fat content is regulated to 4% - 6%, and yak milk fat globule membrane is centrifugally extracted from the defatted raw milk, which not only effectively recovers bioactive components but also improves the nutritional value of the raw materials;

[0068] In S2, the inner layer: lactase and yak whey protein are cross-linked at 4°C to form a rigid gastric acid-resistant protective layer, ensuring that the enzyme activity retention rate in gastric juice is ≥90%;

[0069] The middle layer: sodium alginate is cross-linked through a calcium chloride-calcium lactate composite solution to form a pH-responsive gel network, controlling the intestinal targeted release of lactase;

[0070] The outer layer: yak casein micelles and hulless barley β-glucan form an anti-mechanical shear barrier through fluidized bed spraying. At the same time, β-glucan promotes the balance of intestinal flora as a prebiotic;

[0071] In S3, various raw materials such as yak milk solids and whey protein powder are fully mixed to achieve the complementary advantages of nutritional components and build a comprehensive and balanced nutritional system. Subsequently, yak milk fat globule membrane is added, and two-stage homogenization treatment is carried out. The first stage is to break fat globules under high pressure, and the second stage is to disperse and emulsify under low pressure, ensuring that the fat globule particle size is uniformly refined, and all nutritional components are evenly distributed in the system, thereby improving the reconstitutability and taste of the product and increasing the bioavailability of nutrients, enabling the human body to better absorb the nutrients in the milk powder;

[0072] In S4, the ultra-high pressure sterilization technology uses instantaneous high pressure to destroy the cell membrane and protein structure of microorganisms, achieving efficient sterilization and avoiding the destruction of heat-sensitive nutritional components by high temperature. Subsequently, the vacuum concentration process quickly evaporates water in a low-temperature environment below 60°C, reducing the energy consumption in the subsequent drying process and retaining the flavor and nutrition of the milk powder to the greatest extent, achieving the dual guarantee of safety and nutrition;

[0073] In S5, low-temperature spray drying controls the particle water content ≤4%, avoiding protein denaturation (and the oxidation of conjugated linoleic acid concentrate caused by high temperature), and fluidized bed agglomeration granulation is carried out. The hot air circulation makes the particles form a porous structure, significantly improving the dissolution speed. At the same time, lecithin is sprayed to further optimize the dispersibility, ensuring no caking during reconstitution.

[0074] In S1, the centrifugal separation controls the centrifugal temperature to be less than 10°C, the rotation speed is controlled at 8000 - 10000 rpm, and the sphingomyelin retention rate is ≥90%.

[0075] Specifically, low temperature can inhibit the activities of lipoxygenase and protease, preventing the loss of heat-sensitive components such as sphingomyelin due to thermal denaturation or hydrolysis, ensuring that the retention rate of sphingomyelin is ≥90%. The specific rotation speed stably generates centrifugal force to separate the milk fat globule membrane from the skim milk phase, while maintaining the structural integrity of the milk fat globule membrane and ensuring the biological activity of its functional glycoproteins and phospholipid bilayer structure.

[0076] In S2, the concentration of the composite solution of calcium chloride and calcium lactate is 0.5 mol / L, and the molar ratio is 1:2.

[0077] The mass ratio of yak casein micelles to hulless barley β-glucan mixture is 3:1, and the purity of β-glucan is ≥80%.

[0078] Specifically, the composite solution of calcium chloride and calcium lactate achieves gradient crosslinking by regulating the calcium ion release rate. Among them, calcium chloride rapidly releases calcium ions and combines with the carboxyl groups of sodium alginate to form a dense crosslinked network, enhancing the stability of the intermediate layer in the gastric acid environment. Among them, calcium lactate slowly releases calcium ions, and due to the competitive chelation of lactate ions under alkaline intestinal conditions, the gel network is gradually dissociated, triggering the targeted release of lactase and avoiding premature loss of enzyme activity.

[0079] In the mixture of yak casein micelles and hulless barley β-glucan, casein micelles form a dense outer barrier through hydrophobic interactions and hydrogen bonds, resisting mechanical shear and digestion enzyme degradation, and balancing the requirements of structural strength and functional release.

[0080] In S3, the first-stage homogenization pressure of the two-stage homogenization treatment is 15 - 20 MPa, and the second-stage homogenization pressure is 5 - 8 MPa.

[0081] Specifically, the first-stage high-pressure homogenization (15 - 20 MPa): uses high shear force to break natural fat globules to a particle size of ≤1 μm, breaks the aggregation trend of fat globules, prevents fat from floating and stratifying, and at the same time increases the specific surface area of fat globules, improving the uniform dispersion and absorption rate of fat-soluble components.

[0082] The second-stage low-pressure homogenization (5 - 8 MPa): stabilizes the emulsion system through gentle shear force, repairs the protein-phospholipid membrane structure on the surface of fat globules after the first-stage homogenization, reduces the interfacial tension fluctuation, and ensures the thermal stability of the emulsion during subsequent sterilization and concentration processes.

[0083] In S4, the pressure of ultra-high pressure sterilization is controlled at 500 - 600 MPa, the time is 3 - 5 minutes, and the retention rate of immunoglobulin activity is ≥90%.

[0084] Specifically, ultra-high hydrostatic pressure destroys the cell membranes, cell walls and enzyme systems of microorganisms, with an inactivation rate of ≥99.9% for Gram-negative bacteria and ≥90% for spores, and the safety meets the commercial sterility standard.

[0085] Example 1

[0086] Formula:

[0087] Yak milk solids: 93 parts

[0088] Whey protein powder: 4 parts

[0089] Fructooligosaccharide (FOS): 1.5 parts

[0090] Compound vitamin and mineral: 0.5 part

[0091] Lactase microcapsule: 0.1 part

[0092] Yak milk fat globule membrane (MFGM): 0.6 part

[0093] Conjugated linoleic acid: 0.2 part

[0094] Soybean lecithin: 0.2 part

[0095] Process:

[0096] S101, Centrifugal separation: Temperature 8°C, rotation speed 9000 rpm, retention rate of sphingomyelin in yak milk fat globule membrane 92%;

[0097] S102, Lactase microcapsule: Calcium chloride - calcium lactate composite solution (0.5 mol / L, molar ratio 1:2), outer layer β - glucan purity 85%;

[0098] S103, Mixing and homogenization, Mix yak milk solids, whey protein powder, fructooligosaccharide, compound vitamin and mineral, seabuckthorn flavonoid extract, conjugated linoleic acid concentrate, add to yak milk fat globule membrane and conduct two - stage homogenization treatment to obtain yak milk nutrient mixture;

[0099] S104, Ultra - high pressure sterilization: Pressure 550 MPa, time 4 minutes, retention rate of immunoglobulin activity 92%.

[0100] S105, Drying and granulation, After low - temperature spray drying, obtain yak milk powder through fluidized bed agglomeration granulation.

[0101] Example 2

[0102] Formula:

[0103] Yak milk solids: 94 parts (partially skimmed, fat content 4.5%)

[0104] Whey protein powder: 3.5 parts

[0105] Fructooligosaccharide: 1.8 parts

[0106] Compound vitamin and mineral: 0.6 part

[0107] Lactase microcapsule: 0.15 parts

[0108] Yak milk fat globule membrane: 0.4 parts

[0109] Conjugated linoleic acid: 0.15 parts

[0110] Sunflower lecithin: 0.25 parts

[0111] Process: The steps different from those in Example 1 are

[0112] S201 Centrifugal separation: Temperature 9°C, rotation speed 8500 rpm, MFGM sphingomyelin retention rate 91%;

[0113] S202 Lactase microcapsule: Outer layer β-glucan purity 82%;

[0114] S204 Ultra-high pressure sterilization: Pressure 580 MPa, time 3.5 minutes, immunoglobulin activity retention rate 91%.

[0115] Example 3

[0116] Formula:

[0117] Yak milk solids: 92 parts

[0118] Whey protein powder: 5 parts

[0119] Fructooligosaccharide: 1.2 parts

[0120] Compound vitamin and mineral: 0.4 parts

[0121] Lactase microcapsule: 0.2 parts

[0122] Yak milk fat globule membrane: 0.8 parts

[0123] Conjugated linoleic acid: 0.3 parts

[0124] Soybean lecithin: 0.3 parts

[0125] Process: The steps different from those in Example 1 are

[0126] S301 Centrifugal separation: Temperature 7°C, rotation speed 10000 rpm, yak milk fat globule membrane sphingomyelin retention rate 93%;

[0127] S302 Lactase microcapsule: Outer layer β-glucan purity 88%;

[0128] S304 Ultra-high pressure sterilization: Pressure 600 MPa, time 3 minutes, immunoglobulin activity retention rate 93%.

[0129] Table 1 shows the comparison of the applicable populations of yak milk powder in each example

[0130]

[0131] Among them, by adjusting the proportion of components such as yak milk fat globule membrane, conjugated linoleic acid, lactase, etc., the needs of infants and young children, the elderly and sports people are covered.

[0132] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A formula of yak milk powder with high nutritional value, characterized in that: include: 92-95 parts of yak milk solids, 3-5 parts of whey protein powder, 1-2 parts of oligofructose, 0.3-0.6 parts of multivitamins and minerals, 0.05-0.2 parts of lactase microcapsules, 0.05-0.2 parts of seabuckthorn flavonoids extract, 0.3-0.8 parts of yak milk fat globule membrane, 0.1-0.3 parts of conjugated linoleic acid concentrate and 0.1-0.3 parts of emulsifier; The yak milk solids are derived from the raw milk of yaks in the Qinghai-Tibet Plateau pasture, with a fat content of ≥6%, a protein content of ≥5%, and an immunoglobulin IgG content of ≥2 mg / g and a lactoferrin content of ≥80 mg / 100 g in the milk powder; The multivitamin mineral comprises vitamin D3, vitamin K2-MK7, calcium and iron.

2. The formula of the high nutritional value yak milk powder according to claim 1, characterized in that: The emulsifier includes soybean lecithin or sunflower lecithin, the particle size is ≤50 μm, and the solubility of milk powder is ≥98%.

3. The formula of the high nutritional value yak milk powder according to claim 1, characterized in that: The lactase microcapsules include: The inner layer is a complex of yak whey protein and lactase, of which lactoferrin accounts for ≥10%; The middle layer is sodium alginate, and the cross-linking agent is a composite solution of calcium chloride and calcium lactate; The outer layer is a mixture of yak casein micelles and highland barley β-glucan, with a β-glucan purity of ≥80%; The lactase activity is ≥6000 ALU / g.

4. The formula of the high nutritional value yak milk powder according to claim 1, characterized in that: The yak milk fat globule membrane is extracted from yak raw milk by low-temperature centrifugal separation technology, and the sphingomyelin content is ≥15%.

5. The formula of the high nutritional value yak milk powder according to claim 1, characterized in that: The conjugated linoleic acid concentrate is obtained by extracting yak milk fat through supercritical CO2, and the proportion of the conjugated linoleic acid concentrate in total fatty acids is ≥1.5%.

6. A method for preparing yak milk powder with high nutritional value, characterized in that: A formula for a high nutritional value yak milk powder as claimed in any one of claims 1 to 5, the method comprising the following steps: S1. Pretreatment of raw materials: filtering the raw milk of Tibetan Plateau yak at 4°C, centrifuging and defatting to adjust the fat content to 4% to 6%, and extracting yak milk fat globule membrane from the defatted raw milk by centrifugal separation; S2, lactase microcapsule preparation, lactase and yak whey protein solution are mixed, and the mixture is placed at 4°C for cross-linking to form an inner layer, and then a sodium alginate solution is sprayed on the surface of the inner layer, and then immersed in a composite solution of calcium chloride and calcium lactate for cross-linking to form an intermediate layer, and finally the outer layer is coated with a mixture of yak casein micelles and highland barley β-glucan by fluidized bed spraying technology; S3, mixing and homogenizing, mixing yak milk solids, whey protein powder, oligofructose, complex vitamins and minerals, seabuckthorn flavonoid extract, and conjugated linoleic acid concentrate, adding the mixture into yak milk fat globule membrane for two-stage homogenization to obtain a yak milk nutrient mixture; S4, sterilization and concentration, sterilizing the yak milk nutrient mixture by ultra-high pressure sterilization process, and then passing it into vacuum concentration equipment to concentrate it to a solid content of 45% to 50% and an evaporation temperature of less than 60 degrees Celsius; S5, drying and granulation, after low-temperature spray drying, yak milk powder is obtained by fluidized bed agglomeration granulation, wherein the particle size is 80-200 μm and the dissolution time is ≤15 seconds.

7. The method for preparing yak milk powder with high nutritional value according to claim 6, characterized in that: In the centrifugal separation in S1, the centrifugal temperature is controlled to be less than 10° C., the rotation speed is controlled to be 8000-10000 rpm, and the sphingomyelin retention rate is ≥90%.

8. The method for preparing yak milk powder with high nutritional value according to claim 6, characterized in that: The concentration of the composite solution of calcium chloride and calcium lactate in S2 is 0.5 mol / L, and the molar ratio is 1:2; The mass ratio of the yak casein micelles to the highland barley beta-glucan mixed liquid is 3:1, and the purity of the beta-glucan is ≥80%.

9. The method for preparing yak milk powder with high nutritional value according to claim 6, characterized in that: The first-stage homogenization pressure of the two-stage homogenization treatment in S3 is 15-20 MPa, and the second-stage homogenization pressure is 5-8 MPa.

10. The method for preparing yak milk powder with high nutritional value according to claim 6, characterized in that: The pressure of the ultra-high pressure sterilization in S4 is controlled at 500-600 MPa, the time is 3-5 minutes, and the immunoglobulin activity retention rate is ≥90%.

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