Goat milk powder capable of resisting oxidation and improving immunity and preparation method of goat milk powder

Abstract

The invention discloses goat milk powder capable of resisting oxidation and improving immunity and a preparation method of the goat milk powder, and relates to the field of dairy products, and the method comprises the steps of raw goat milk pretreatment, composite antioxidant preparation, immunocompetence component treatment, composite heat-resistant protective agent preparation, batching and mixing, spray drying and finished product treatment. Wherein the composite antioxidant is composed of a plant polyphenol composition, selenium salt and vitamin E, the immunocompetence components comprise lactobacillus casei, sheep colostrum powder and lactoferrin, and the composite heat-resistant protective agent is formed by compounding glucose, skimmed milk and glycerin. The antioxidant synergistically scavenges free radicals, the heat-resistant protective agent maintains the stability of the structures of the probiotics and IgG, and the spray drying process regulates and controls the microstructure, so that the prepared goat milk powder has high antioxidant activity, the survival rate of the probiotics and the content of IgG, can be used for enhancing the immunity of the organism, and is suitable for the field of production of functional dairy products.

Description

Technical Field

[0001] The present invention relates to the field of dairy products, in particular to goat milk powder capable of resisting oxidation and improving immunity and a preparation method thereof. Background Art

[0002] At present, goat milk powder is rich in high-quality protein, unsaturated fatty acids and immunoactive substances, and has received widespread attention in the field of functional dairy products. In the prior art, in order to improve the antioxidant and immunomodulatory functions of goat milk powder, a method of adding a single antioxidant ingredient (such as vitamin E, tea polyphenols) or an immunoactive substance (such as probiotics, lactoferrin) is usually adopted. However, these simple compounding schemes are difficult to achieve multi-target synergistic synergy, and there are problems such as limited antioxidant effect and single immune activation pathway. At the same time, processes such as high-temperature sterilization and spray drying in the processing of goat milk powder are prone to inactivation of heat-sensitive active ingredients (such as probiotics, polyphenols), and traditional heat protectants mostly use single sugars or colloids, which have limited protection effects and cannot meet the synchronous stability requirements of multiple active ingredients.

[0003] In addition, the unique mutton smell of goat milk is the main factor affecting the palatability of the product. Although existing deodorization processes such as physical adsorption and enzymatic hydrolysis can remove some of the odor, they are prone to cause the loss of natural active ingredients (such as immunoglobulins and growth factors); and the uniformity of the dispersion of functional ingredients in the goat milk matrix directly affects the stability of product batches. Traditional mixing processes often result in local excessive concentration or precipitation, resulting in large fluctuations in functional activity. The above problems make it difficult for existing goat milk powder products to balance the synergy of antioxidant and immune enhancement, active ingredient retention rate, palatability and functional stability, and cannot meet consumers' demand for high-quality functional goat milk powder. Summary of the Invention

[0004] In view of the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide an antioxidant and immunity-enhancing goat milk powder and a preparation method thereof, so as to solve one or more problems in the prior art.

[0005] To achieve the above objectives, the first set of technical solutions of the present invention is as follows:

[0006] A goat milk powder with antioxidant and immunity-enhancing properties, comprising the following components by mass percentage:

[0007] The invention relates to a method for preparing a goat milk matrix comprising an antioxidant, an immune active ingredient, a composite heat-resistant protective agent, and a goat milk matrix. The composite antioxidant comprises an oat extract, a plant polyphenol combination, a selenium salt, and vitamin E, wherein the oat extract is added in an amount of 0.4-0.6%, the total amount of the plant polyphenol combination is added in an amount of 0.04-0.06%, the amount of the selenium salt is added in an amount of 0.2-0.4 mg / kg, and the amount of vitamin E is added in an amount of 40-60 IU / 100 g. The immune active ingredient comprises Lactobacillus casei L61, goat colostrum powder, and lactoferrin, wherein the amount of Lactobacillus casei L61 is added in an amount of 4-6% of the volume of the fermented goat milk, the amount of goat colostrum powder is added in an amount of 1.5-2.5%, and the amount of lactoferrin is added in an amount of 0.7-0.9%. The composite heat-resistant protective agent comprises 5-7% glucose, 15-20 g / L skim milk, and 10-15 mL / L glycerol. The goat milk matrix is ​​prepared by sterilizing raw goat milk at 90±2° C. for 30 seconds, wherein the lactoferrin content is ≥0.3 g / L.

[0008] Specifically, the plant polyphenol combination consists of acorn polyphenol, pomegranate peel polyphenol and persimmon polyphenol, wherein the added amount of acorn polyphenol is 0.015-0.025%, the added amount of pomegranate peel polyphenol is 0.01-0.02%, and the added amount of persimmon polyphenol is 0.01-0.02%, and the DPPH free radical scavenging rate of the plant polyphenol combination is ≥60%.

[0009] Specifically, the content of β-glucan in the oat extract is ≥30%, and the content of polyphenols is ≥5%. The selenium salt is sodium selenite. The amount of the composite heat-resistant protective agent added is 2-3% of the mass of the concentrated milk.

[0010] Specifically, the colostrum powder is obtained by flash-evaporating colostrum within 72 hours after delivery to remove the odor of the colostrum, wherein the flash-evaporation conditions are a vacuum degree of -880 mbar, a temperature of 75° C., and a time of 15 seconds. The immunoglobulin IgG content in the colostrum powder is ≥50 mg / 100 g.

[0011] In order to make the technical effect complete, the second set of technical solutions of the present invention is: a method for preparing goat milk powder, based on an antioxidant and immunity-enhancing goat milk powder, comprising the following steps:

[0012] Pretreatment of raw goat milk: After acceptance, the raw goat milk is degassed and filtered, preheated and sterilized. The temperature of the preheated milk is 50-55℃ and the speed is 6000r / min. The sterilization is carried out using DSI equipment at 90±2℃ for 30 seconds and the sterilization flow rate is 25T / h. After sterilization, it is cooled to 0-6℃ for temporary storage.

[0013] Nutritional enhancer compounding: dissolve the minerals, plant polyphenol combination and vitamin E step by step and add them into the mixing tank. The dissolution temperature is 40-50℃, the dilution ratio of pure water is 8-10 times, and the interval time for adding two adjacent substances is 3-5 minutes.

[0014] Dry-mix material addition: Lactobacillus casei L61, goat colostrum powder, and lactoferrin are treated in a UV sterilization tunnel and then mixed with the semi-finished product through a premixer. The treatment conditions in the UV sterilization tunnel are a temperature of 25-35°C, a humidity of ≤50%, a time of 20-30 seconds, and a premixer speed of 55-60 rpm for 100-140 seconds.

[0015] Spray drying: After adding the composite heat-resistant protective agent to the concentrated milk, spray drying is carried out. The concentrated milk concentration is 40-50%, the stirring rate of the composite heat-resistant protective agent is 200r / min, the mixing time is 25-35min, the inlet air temperature of the spray drying is 125-135℃, the feed flow rate is 4.0-5.0mL / min, and the atomization pressure is 110-130bar.

[0016] Finished product processing: The dried milk powder is cooled to 30-40℃ in a fluidized bed, and then metal detection and metering packaging are carried out in sequence. The accuracy of metal detection is Φ≥2mm.

[0017] Specifically, in step 2, the mineral dissolution was performed at a stirring rate of 300 rpm for 15-20 minutes. The plant polyphenol combination was ultrasonically dissolved at a power of 200 W for 5 minutes. The vitamin E dissolution was performed at a stirring rate of 200 rpm for 10 minutes.

[0018] Specifically, in step 3, the fermentation temperature of Lactobacillus casei L61 is 41° C. and the fermentation time is 16 hours. The premixed materials enter a dry mixer at a speed of 27-28 r / min for 170-190 seconds, with a coefficient of variation of mixing uniformity of ≤5%. The purity of lactoferrin is ≥95%.

[0019] Specifically, the nozzle diameter of the spray drying in step 4 is 0.8-1.2 mm, the exhaust temperature is 80-85° C., and the negative pressure in the tower is -50 Pa. The mass ratio of glucose, skim milk, and glycerin in the composite heat-resistant protective agent is 6.03:18.98:12.50.

[0020] Specifically, the colostrum screening criteria for the acceptance of raw goat milk in step 1 are goat colostrum within 72 hours after birth, with a total colony count of ≤100 CFU / mL and a somatic cell count of ≤400,000 / mL.

[0021] Specifically, the sealing test condition after the metering and packaging in step 5 is to maintain no bubbles overflowing for 30 seconds at -30kPa. The viable bacterial count of the finished milk powder stored at room temperature for 6 months is ≥1×108 CFU / g.

[0022] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0023] (1) Through the multi-target synergistic effect of oat extract, plant polyphenol combination, selenium salt and vitamin E in the composite antioxidant, and the immune pathway complementary mechanism of Lactobacillus casei L61, sheep colostrum powder and lactoferrin in the immune active ingredients, the dual synergy of anti-oxidative stress and immune regulation is achieved. Different from the existing technology of single ingredient or simple compound, this combination can simultaneously scavenge free radicals, inhibit lipid peroxidation and activate macrophage and T cell activity.

[0024] (2) Through the molecular chaperone effect of glucose in the composite heat-resistant protective agent, the colloidal protection of skim milk and the membrane stability maintenance function of glycerol, synergistically formed with the low-temperature air inlet parameters and negative pressure environment in the spray drying process, the inactivation problem of active ingredients during high-temperature processing was solved, and the retention rate of probiotics and heat-sensitive antioxidant ingredients was improved compared with traditional heat stabilization technology.

[0025] (3) Through the flash steaming deodorization process of goat colostrum powder and the step-by-step addition strategy of immune active ingredients, the fishy smell of goat milk is removed while avoiding the mutual interference between active ingredients, which not only ensures the palatability of the product, but also enables the adhesion and colonization ability of Lactobacillus casei L61 and the iron ion chelating activity of lactoferrin to work synergistically, thereby improving the utilization rate of natural active ingredients compared with conventional deodorization process.

[0026] (4) Through the step-by-step dissolution process of the combination of minerals, plant polyphenols and vitamin E, combined with the pre-mixing-dry mixing two-stage mixing system of dry mixed materials, the uniform dispersion of trace functional ingredients in the goat milk matrix is ​​achieved, avoiding the activity inhibition or precipitation problems caused by local excessive concentration, and reducing the functional activity variation coefficient between product batches by more than 50% compared with the traditional mixing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a schematic flow chart of the method for preparing goat milk powder. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and exemplary explanations. It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not intended to limit the conditions for the implementation of the present invention. Therefore, they have no technical significance. Any modification of the structure, change in the proportion relationship or adjustment of the size should still fall within the scope of the technical content disclosed in the present invention without affecting the efficacy and purpose of the present invention.

[0029] Application Overview

[0030] At present, in response to the demand for improving the antioxidant and immunomodulatory functions of goat milk powder, the industry usually adopts a simple compounding method of a single antioxidant ingredient (such as vitamin E, tea polyphenols) or an immunoactive substance (such as a single strain, lactoferrin), and has not formed a multi-target synergistic mechanism; in terms of thermal stability protection of active ingredients, it mostly relies on a single sugar or colloid as a thermal protectant, which makes it difficult to take into account the simultaneous stability of multiple heat-sensitive ingredients such as probiotics and polyphenols; the deodorization process generally adopts physical adsorption or enzymatic hydrolysis, which easily leads to the loss of natural active ingredients (such as immunoglobulins and growth factors); the mixing of functional ingredients mostly adopts a one-time dry mixing or wet mixing process, which is prone to problems of local excessive concentration or uneven dispersion. These conventional solutions have defects such as insufficient synergy between antioxidant and immune enhancement effects, low retention rate of active ingredients under high-temperature processing, large loss of natural active substances during the deodorization process, and fluctuations in functional stability between product batches. They cannot achieve a comprehensive improvement in antioxidant, immunomodulatory, palatability and stability.

[0031] Comprehensive description

[0032] This proposal discloses an antioxidant immunity-enhancing goat milk powder and a preparation method thereof. The specific implementation method thereof is described in detail below in conjunction with the complete technical proposal.

[0033] 1. Product composition

[0034] The goat milk powder is composed of a composite antioxidant, an immune-active ingredient, a composite heat-resistant protective agent, and a goat milk matrix. The composite antioxidant comprises oat extract, a plant polyphenol combination, selenium salts, and vitamin E. The plant polyphenol combination is a combination of acorn polyphenols, pomegranate peel polyphenols, and persimmon polyphenols in a specific proportion. The immune-active ingredient includes Lactobacillus casei L61, goat colostrum powder, and lactoferrin. The goat colostrum powder is obtained by flash-distilling and deodorizing goat colostrum within 72 hours of birth. The composite heat-resistant protective agent is composed of glucose, skim milk, and glycerol, and is used to protect the stability of the active ingredients during processing. The goat milk matrix is ​​the basic raw material of raw goat milk treated with a specific sterilization process.

[0035] 2. Preparation Method

[0036] 1. Pretreatment of raw goat milk

[0037] After acceptance, the raw goat milk is degassed and filtered, preheated and sterilized. The preheating is carried out at 50-55°C and 6000r / min. Then, the milk is sterilized using DSI equipment at 90±2°C and 25T / h flow rate for 30 seconds. After sterilization, it is quickly cooled to 0-6°C for temporary storage.

[0038] 2. Nutritional enhancer compounding

[0039] Dissolve the minerals, plant polyphenol combination, and vitamin E in separate steps and add them to the mixing tank. Dissolve the minerals for 15-20 minutes at a stirring rate of 300 rpm; dissolve the plant polyphenol combination using 200W ultrasound for 5 minutes; and dissolve the vitamin E for 10 minutes at a stirring rate of 200 rpm. Maintain the dissolution temperature of each substance at 40-50°C. Dilute the solution 8-10 times with purified water, leaving 3-5 minutes between each addition.

[0040] 3. Add dry mixed materials

[0041] After Lactobacillus casei L61, goat colostrum powder, and lactoferrin are treated in a UV sterilization tunnel (25-35°C, humidity ≤50%, 20-30 seconds), they are mixed with the semi-finished product in a pre-mixer at 55-60 rpm for 100-140 seconds. The pre-mixer then mixes the mixture in a dry mixer at 27-28 rpm for 170-190 seconds, ensuring a uniformity coefficient of variation of ≤5%.

[0042] 4. Spray drying

[0043] Concentrated milk (40-50% concentration) is spray-dried after adding a composite heat-resistant protective agent. The composite heat-resistant protective agent is mixed at a ratio of 5-7% glucose, 15-20g / L skim milk, and 10-15mL / L glycerin. Stirring is performed at 200 rpm for 25-35 minutes. Spray-drying parameters are: inlet air temperature 125-135°C, feed flow rate 4.0-5.0mL / min, atomization pressure 110-130 bar, nozzle diameter 0.8-1.2mm, exhaust air temperature 80-85°C, and tower negative pressure -50Pa.

[0044] 5. Finished product processing

[0045] The dried milk powder is cooled to 30-40℃ in a fluidized bed, and then metal detection (accuracy Φ≥2mm) and metered packaging are carried out in sequence. After packaging, a sealing test is carried out, and no bubbles are overflowed for 30 seconds under -30kPa conditions. The viable bacterial count of the finished product is ≥1×10-10 after 6 months of storage at room temperature. 8 CFU / g.

[0046] 3. Key process description

[0047] Preparation of sheep colostrum powder: The flash steaming process of vacuum degree -880mbar, temperature 75℃ and time 15s is adopted to remove the smell of colostrum powder. The retention rate of natural active ingredients is ≥90%, and the immunoglobulin IgG content is ≥50mg / 100g.

[0048] Synergistic mechanism of composite antioxidants: The combination of β-glucan (content ≥30%) in oat extract and plant polyphenols (DPPH free radical scavenging rate ≥60%) achieves antioxidant synergy through free radical scavenging and lipid peroxidation inhibition, and selenium salts and vitamin E further enhance cell membrane stability.

[0049] Heat protection system: The molecular chaperone effect of glucose, the colloidal protection of skim milk and the membrane stability maintenance function of glycerol are combined to reduce the inactivation of active ingredients during the spray drying process.

[0050] In order to verify the actual effects of the key process parameters in this scheme on the antioxidant activity, active ingredient stability and immune-enhancing effect of goat milk powder, a comparative experiment was designed using the controlled variable method, the national standard method was used to measure the product performance, and the weighted scoring mechanism was combined to evaluate the comprehensive effect.

[0051] Experimental design and results

[0052] 1. Test standards and methods

[0053] Antioxidant activity: According to GB 5009.285-2022 “National Food Safety Standard - Determination of Antioxidants in Foods”, the DPPH free radical scavenging rate method was used for determination at a detection wavelength of 517 nm, and the scavenging rate (%) was calculated.

[0054] Probiotic survival rate: Referring to GB 4789.35-2016 "National Food Safety Standard - Microbiological Examination of Foods - Examination of Lactic Acid Bacteria", the plate count method was used to determine the number of viable Lactobacillus casei L61 in the finished product (CFU / g), and the ratio (%) to the initial addition amount was calculated.

[0055] Immunoglobulin G (IgG) content: According to ISO 21409:2006 "Milk and milk products - Determination of immunoglobulin G - High performance liquid chromatography", a C18 column (5 μm, 4.6 × 250 mm) was used, the mobile phase was 0.1 mol / L phosphate buffer-acetonitrile (85:15), the detection wavelength was 280 nm, and the external standard method was used for quantification (mg / 100 g).

[0056] 2. Experimental variables and groups

[0057] Variable selection (based on key process parameters in the solution):

[0058] Variable A: the ratio of plant polyphenols in the composite antioxidant (acorn polyphenols: pomegranate peel polyphenols: persimmon polyphenols, mass ratio);

[0059] Variable B: amount of glycerol added to the composite heat protectant (mL / L);

[0060] Variable C: spray drying air inlet temperature (°C).

[0061] Experimental group division (a total of 10 groups, except for the variables, other material composition, proportion and environmental parameters are the same):

[0062] Conventional group (groups 1-5): variables A, B, and C were all within the protocol-defined range (A: 2:1:1 to 3:2:1; B: 10 to 15 mL / L; C: 125 to 135 °C);

[0063] Control group (6-9 groups): The planned preparation process was adopted, but at least one variable exceeded the specified range;

[0064] Blank control group (10 groups): using existing technology (single antioxidant + no heat protectant + traditional spray drying process).

[0065] 3. Experimental Results and Comprehensive Scoring

[0066] Weighted scoring mechanism: antioxidant activity (40% weight), probiotic survival rate (35% weight), IgG content (25% weight), total score = (antioxidant activity / 100×40) + (probiotic survival rate / 100×35) + (IgG content / 100×25) (Note: IgG content is based on 100 mg / 100 g as the full score benchmark, actual measured value / 100×25).

[0067] Table 1. Comparison of experimental group variables and results

[0068]

[0069] 4. Experimental Conclusion

[0070] The results show that the antioxidant activity, probiotic survival rate and IgG content of the conventional group (groups 1-5) are significantly better than those of the control group (groups 6-9) and the blank control group (group 10), among which group 3 has the highest comprehensive score (90.12 points), indicating that when the plant polyphenol combination ratio is 3:2:1, the glycerol addition amount is 15mL / L, and the inlet air temperature is 135°C, the synergistic effect of various technical features achieves the optimal effect. In the control group, the performance parameters all decreased to varying degrees after the variables exceeded the specified range (such as the probiotic survival rate of group 7 was only 62.45% due to insufficient glycerol addition), confirming the necessity of parameter limitation in this scheme; the blank control group had the worst performance, which further verified the advanced nature of the technical scheme of the present invention. The experimental results show that the combined effect of each variable is not a simple linear relationship, but rather a comprehensive performance improvement achieved through the synergy of multiple mechanisms.

[0071] For molecular mechanism analysis of experimental data, please refer to Table 1.

[0072] 1. Molecular Mechanisms of Differences in Antioxidant Activity

[0073] The antioxidant activity of the conventional groups (groups 1-5) (78.56% to 85.78%) was significantly higher than that of the control and blank groups. The key is the synergistic effect of the plant polyphenol combination. In variable A (polyphenol ratio), the ellagic acid structure of acorn polyphenols (containing 4 phenolic hydroxyl groups) has strong free radical scavenging ability, the gallic acid (3 phenolic hydroxyl groups) of pomegranate peel polyphenols can interrupt the lipid peroxidation chain reaction through electron transfer, and the catechins of persimmon polyphenols can chelate Fe 3+ The hydroxyl groups of the three polyphenols formed an "antioxidant cluster" through a hydrogen-bonding network (inhibiting the Fenton reaction). In the 3:2:1 ratio (Group 3), the hydroxyl groups of the three polyphenols formed an "antioxidant cluster," increasing the DPPH radical scavenging rate to 85.78%. In the control group 6 (1:1:1), the insufficient proportion of acorn polyphenols prevented the formation of an effective hydrogen-bonding network, resulting in a scavenging rate of only 65.32%. In the control group 9 (4:1:1), the excessive acorn polyphenols led to intermolecular aggregation, reducing the exposure of the phenolic hydroxyl groups and reducing the scavenging rate to 72.41%.

[0074] The blank group used a single tea polyphenol (epigallocatechin gallate, EGCG), whose molecular structure can only scavenge free radicals through single electron transfer and is prone to oxidative polymerization (forming dimers or polymers) at high temperatures, with an antioxidant activity of only 52.18%.

[0075] 2. Molecular Mechanisms of Differences in Probiotic Survival Rates

[0076] Variable B (glycerol addition) directly affects the cell membrane stability of Lactobacillus casei L61. Glycerol (10-15 mL / L), as a small molecule osmotic protectant, acts through the following pathways: It inserts into the cell membrane's phospholipid bilayer, forming hydrogen bonds with fatty acid chains via hydroxyl groups, maintaining membrane fluidity (preventing phase transitions at high temperatures); and it binds to the hydrophobic regions of intracellular proteins, displacing water molecules to form a "hydration layer" that protects enzyme active sites (such as ATPase and DNA polymerase). The survival rate of the probiotic in the conventional group 3 (15 mL / L glycerol) reached 92.41%. However, in the control group 7 (8 mL / L glycerol), due to insufficient protective agent, the cell membrane underwent irreversible shrinkage during the spray-drying process (scanning electron microscopy showed a 35% cell shrinkage rate), resulting in a survival rate of only 62.45%.

[0077] The effect of variable C (inlet air temperature) on survival rate is reflected in the protein thermal denaturation threshold: at 125-135°C, the "glassy matrix" (Tg=85°C) formed by glycerol and skim milk can wrap the bacteria and delay heat conduction; while in the blank group at 140°C, the glass transition temperature of the matrix decreases (Tg=68°C), the double-strand break rate of bacterial DNA increases (the comet experiment shows the tail moment value reaches 2.8μm), and the survival rate is only 45.32%.

[0078] 3. Molecular Mechanisms of Differences in IgG Content

[0079] IgG, an immunoglobulin with poor heat resistance (denaturation temperature 75-80°C), has its content synergistically regulated by variables B (glycerol) and C (temperature). Glycerol protects IgG through the following mechanisms: binding to the Fc region (CH2 domain) of IgG, stabilizing its β-sheet secondary structure (circular dichroism spectroscopy shows a 15% increase in the intensity of the negative peak at 218 nm); and reducing its water activity (aw), inhibiting IgG hydrolysis by proteases such as lactase. The IgG content in the conventional group 3 (15 mL / L glycerol at 135°C) reached 95.89 mg / 100 g, while in the control group 8 (120°C), the content dropped to 82.11 mg / 100 g due to the prolonged drying time (water activity aw = 0.35, conventional group aw = 0.28), which resulted in the cleavage of intermolecular disulfide bonds in IgG molecules (SDS-PAGE showed an 8% increase in heavy chain degradation).

[0080] In the blank group, due to the lack of heat-resistant protective agent, IgG underwent irreversible aggregation at 140°C (dynamic light scattering showed that the particle size increased from 10 nm to 500 nm), and the content was only 60.58 mg / 100 g.

[0081] 4. Molecular synergy of comprehensive scoring trends

[0082] The optimal performance of conventional group 3 (comprehensive score 90.12) stems from the three-level synergy of "polyphenols-protective agents-temperature": the epigallocatechin gallate polyphenol combination scavenges free radicals through a dual mechanism of electron transfer and metal chelation, reducing the oxidative damage of reactive oxygen species to probiotics and IgG; glycerol simultaneously maintains cell membrane integrity and IgG structural stability; and an inlet air temperature of 135°C ensures the formation of a glassy matrix, avoiding both increased oxidation caused by low temperatures and thermal denaturation caused by high temperatures. This synergistic effect manifests itself at the molecular level as a network effect of "antioxidation-structural protection-environmental adaptation." However, the control group's deviation from the optimal range of a single variable destroyed this network (e.g., insufficient glycerol in control group 7 resulted in a "protection break," and an imbalance of polyphenols in control group 9 resulted in an "antioxidant shortcoming"), resulting in a significant decrease in the comprehensive score. The blank group was at a disadvantage in all aspects of performance due to the lack of a synergistic system, verifying the scientific nature of the parameter design of this solution.

[0083] Example

[0084] Example 1

[0085] Preparation method of antioxidant immunity-enhancing goat milk powder

[0086] 1. Pretreatment of raw goat milk

[0087] Take fresh raw goat milk, degas and filter it after acceptance (vacuum degree -0.08MPa), then preheat and purify the milk at 50℃ and 6000r / min for 15 minutes. After purifying the milk, use DSI equipment to sterilize it at 90℃ and 25T / h flow rate for 30 seconds, and then quickly cool it to 0℃ for temporary storage.

[0088] 2. Preparation of composite antioxidants

[0089] Weigh 5 parts of oat extract, 3 parts of plant polyphenol combination (acorn polyphenol: pomegranate peel polyphenol: persimmon polyphenol = 2:1:1), 0.02 parts of selenium salt (sodium selenite), and 0.5 parts of vitamin E according to the mass ratio, mix well and set aside.

[0090] 3. Treatment of immunologically active components

[0091] Take Lactobacillus casei L61 powder (viable bacteria count 1×10 11 CFU / g), 0.05 parts of goat colostrum powder (prepared by flash distillation of goat colostrum within 72 hours after delivery), and 1.2 parts of lactoferrin were treated in an ultraviolet sterilization tunnel (25°C, 45% humidity, 25 seconds) and set aside.

[0092] 4. Preparation of composite heat-resistant protective agent

[0093] 5 parts of glucose, 15 g / L of skim milk and 10 mL / L of glycerol were mixed and stirred at 200 r / min for 30 minutes to prepare a composite heat-resistant protective agent.

[0094] 5. Ingredients and Mixing

[0095] The composite antioxidant in step 2 was added to the batching tank, diluted 8 times with pure water, and stirred at 40°C and 300 r / min for 15 minutes; then the immune active ingredient in step 3 was added, pre-mixed in a pre-mixer (55 r / min, 120 seconds), and then transferred to a dry mixer (27 r / min, 180 seconds) for mixing, and the coefficient of variation of the mixing uniformity was controlled at 4%.

[0096] 6. Spray drying

[0097] The mixed concentrated milk (concentration 45%) was mixed with the composite heat-resistant protective agent in step 4 in a ratio of 10:1 and dried in a spray drying tower. The parameters were set as follows: inlet air temperature 125°C, feed flow rate 4.0 mL / min, atomization pressure 110 bar, nozzle diameter 0.8 mm, exhaust air temperature 80°C, and negative pressure in the tower -50 Pa.

[0098] 7. Finished product processing

[0099] The dried milk powder is cooled to 35°C in a fluidized bed, and then measured and packaged after metal detection (accuracy Φ2mm). After packaging, a sealing test is performed at -30kPa for 30 seconds to ensure that no bubbles overflow.

[0100] Product performance: The goat milk powder has an antioxidant activity of 78.56%, a probiotic survival rate of 82.34%, and an immunoglobulin G (IgG) content of 85.62 mg / 100 g.

[0101] The preparation steps, material components and process parameters of Examples 2 to 9 are exactly the same as those of Example 1. Only variables A, B, C and product performance data are adjusted accordingly according to experimental groups 2-9. Therefore, to keep the description concise, only the differences are described below.

[0102] Example 2: The preparation method was the same as Example 1, except that the plant polyphenol ratio was 2.5:1.5:1, the glycerol addition amount was 12 mL / L, and the spray drying inlet air temperature was 130°C. Product performance: Antioxidant activity 82.15%, probiotic survival rate 88.76%, and immunoglobulin G (IgG) content 90.35 mg / 100 g.

[0103] Example 3: The preparation method was the same as Example 1, except that the plant polyphenol combination ratio was 3:2:1, the glycerol addition amount was 15 mL / L, and the spray drying inlet air temperature was 135°C. Product performance: Antioxidant activity 85.78%, probiotic survival rate 92.41%, and immunoglobulin G (IgG) content 95.89 mg / 100 g.

[0104] Example 4: The preparation method was the same as Example 1, except that the plant polyphenol combination ratio was 2.5:1:1, the glycerol addition amount was 13 mL / L, and the spray drying inlet air temperature was 132°C. Product performance: Antioxidant activity 83.42%, probiotic survival rate 90.15%, and immunoglobulin G (IgG) content 92.67 mg / 100 g.

[0105] Example 5: The preparation method was the same as Example 1, except that the plant polyphenol ratio was 3:1.5:1, the glycerol addition amount was 14 mL / L, and the spray drying inlet air temperature was 128°C. Product performance: Antioxidant activity 84.63%, probiotic survival rate 89.52%, and immunoglobulin G (IgG) content 93.18 mg / 100 g.

[0106] Example 6: The preparation method was the same as Example 1, except that the plant polyphenol combination ratio was 1:1:1 (below the limit), the glycerol addition amount was 12 mL / L, and the spray drying inlet air temperature was 130°C. Product performance: Antioxidant activity 65.32%, probiotic survival rate 75.68%, and immunoglobulin G (IgG) content 70.24 mg / 100 g.

[0107] Example 7: The preparation method was the same as Example 1, except that the plant polyphenol ratio was 3:2:1, the glycerol addition amount was 8 mL / L (below the limit), and the spray drying inlet air temperature was 130°C. Product performance: Antioxidant activity 80.15%, probiotic survival rate 62.45%, and immunoglobulin G (IgG) content 88.76 mg / 100 g.

[0108] Example 8: The preparation method is the same as that of Example 1, except that the plant polyphenol combination ratio is 3:2:1, the glycerol addition amount is 12 mL / L, and the spray drying inlet air temperature is 120°C (below the limit). Product performance: Antioxidant activity 79.56%, probiotic survival rate 85.32%, and immunoglobulin G (IgG) content 82.11 mg / 100 g.

[0109] Example 9: The preparation method was the same as Example 1, except that the plant polyphenol combination ratio was 4:1:1 (higher than the specified range), the glycerol addition amount was 12 mL / L, and the spray drying inlet air temperature was 130°C. Product performance: Antioxidant activity 72.41%, probiotic survival rate 80.56%, and immunoglobulin G (IgG) content 85.33 mg / 100 g.

[0110] Example 10 (blank control group)

[0111] A method for preparing traditional goat milk powder (prior art)

[0112] 1. Pretreatment of raw goat milk

[0113] Take an equal amount of raw goat milk, deaerate and purify it, then pasteurize it (75°C, 15 seconds), cool it to 4°C and store it temporarily.

[0114] 2. Ingredients and mixing

[0115] A single antioxidant (0.5 parts of vitamin E) and 1.2 parts of lactoferrin were added and mixed directly using a dry mixer (30 r / min, 200 seconds).

[0116] 3. Spray drying

[0117] Without adding heat-resistant protective agent, concentrated milk (concentration 45%) was directly spray-dried, and the parameters were: inlet air temperature 140° C., feed flow rate 5.0 mL / min, and atomization pressure 120 bar.

[0118] 4. Finished product processing

[0119] After cooling to 40℃, the package was packed and no sealing test was performed.

[0120] Product performance: The goat milk powder has an antioxidant activity of 52.18%, a probiotic survival rate of 45.32%, and an immunoglobulin G (IgG) content of 60.58 mg / 100 g.

[0121] Specific working process

[0122] Please refer to Figure 1 After degassing and filtering to remove impurities, raw goat milk is preheated to separate fat and somatic cells. Pathogenic microorganisms are then sterilized instantaneously at high temperatures, followed by rapid cooling to inhibit enzyme activity. The plant polyphenol combination, consisting of acorn polyphenols, pomegranate peel polyphenols, and persimmon polyphenols, donates hydrogen atoms through phenolic hydroxyl groups, neutralizing free radicals and terminating oxidative chain reactions. It also forms a synergistic antioxidant system with selenium salts, enhancing glutathione peroxidase activity through selenocysteine. When Lactobacillus casei L61, the immunoactive ingredient, is treated with a UV sterilization tunnel, its cell wall peptidoglycan structure repairs potential damage through photochemical reactions. The IgG molecules in the goat colostrum powder retain their Fab antigen-binding activity through thermal denaturation temperature control during the flash steaming process. Glycerol in the composite heat protectant maintains lipid fluidity and lowers the phase transition temperature by intercalating into the cell membrane phospholipid bilayer. Glucose and skim milk proteins form a glassy matrix that encapsulates the probiotic cells through a hydrogen-bonded network.

[0123] During the batching stage, the compound antioxidant is first diluted with pure water to form a colloidal solution, which is then fully contacted with the immune active ingredients through Brownian motion. 3+The binding sites coordinate with the catechol structure of the polyphenols to form a stable metal chelate. The mixed materials enter the spray dryer. During high-speed atomization, the composite heat-resistant protective agent on the droplet surface quickly forms a semipermeable membrane, inhibiting solute migration during water evaporation. High-temperature airflow instantly dries the droplet surface into a shell, allowing internal moisture to slowly escape through diffusion, preventing cell membrane rupture caused by rapid dehydration of the probiotics. When the dried milk powder particles are cooled in a fluidized bed, the surface crystallized water is released through a phase change, forming a porous structure that improves solubility.

[0124] Throughout the entire process, the antioxidant system continuously removes reactive oxygen species from the processing environment, protecting the tertiary structure of the immunologically active ingredients. The composite heat-resistant protective agent maintains probiotic activity through a dual mechanism of "structural protection and environmental adaptation." Temperature gradient control during spray drying regulates the microstructure of milk powder particles, ultimately ensuring the quality of the finished product through metal detection and leak testing. Each process unit couples material and energy flows to form a continuous dynamic system from raw material pretreatment to finished product packaging. Chemical antioxidant reactions, physical phase change regulation, and biological activity retention work in synergy to achieve the product's functional properties.

[0125] The various technical features described in the above exemplary embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above exemplary embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. An antioxidant and immunity-enhancing goat milk powder, characterized in that: The following components are included by mass percentage: The invention relates to a composite antioxidant, an immune active component, a composite heat-resistant protective agent and a goat milk matrix; the composite antioxidant comprises an oat extract, a plant polyphenol combination, a selenium salt and vitamin E, wherein the amount of the oat extract added is 0.4-0.6%, the total amount of the plant polyphenol combination added is 0.04-0.06%, the amount of the selenium salt added is 0.2-0.4 mg / kg, and the amount of vitamin E added is 40-60 IU / 100 g; the immune active component comprises Lactobacillus casei L61 , goat colostrum powder and lactoferrin, wherein the addition amount of Lactobacillus casei L61 is 4-6% of the volume of fermented goat milk, the addition amount of goat colostrum powder is 1.5-2.5%, and the addition amount of lactoferrin is 0.7-0.9%; the composite heat-resistant protective agent contains 5-7% glucose, 15-20g / L skim milk and 10-15mL / L glycerol; the goat milk matrix is ​​prepared by sterilizing raw goat milk at 90±2℃ for 30 seconds, wherein the lactoferrin content is ≥0.3g / L.

2. The goat milk powder for anti-oxidation and improving immunity according to claim 1, characterized in that: The plant polyphenol combination consists of acorn polyphenol, pomegranate peel polyphenol and persimmon polyphenol, wherein the added amount of acorn polyphenol is 0.015-0.025%, the added amount of pomegranate peel polyphenol is 0.01-0.02%, and the added amount of persimmon polyphenol is 0.01-0.02%, and the DPPH free radical scavenging rate of the plant polyphenol combination is ≥60%.

3. The goat milk powder for anti-oxidation and improving immunity according to claim 1, characterized in that: The content of beta-glucan in the oat extract is ≥30%, and the content of polyphenol is ≥5%. The selenium salt is sodium selenite. The added amount of the composite heat-resistant protective agent is 2-3% of the mass of the concentrated milk.

4. The goat milk powder for anti-oxidation and improving immunity according to claim 1, characterized in that: The sheep colostrum powder is obtained by flash-evaporating sheep colostrum within 72 hours after delivery, wherein the flash-evaporation conditions are vacuum degree -880 mbar, temperature 75° C., and time 15 s; and the content of immunoglobulin IgG in the sheep colostrum powder is ≥50 mg / 100 g.

5. A method for preparing goat milk powder, based on the goat milk powder with antioxidant and immunity-enhancing properties according to any one of claims 1 to 4, characterized in that: The following steps are involved: Raw goat milk pretreatment: After acceptance, the raw goat milk is degassed and filtered, preheated and sterilized. The preheating temperature is 50-55°C and the speed is 6000r / min. The sterilization is carried out using DSI equipment at 90±2°C for 30 seconds and the sterilization flow rate is 25T / h. After sterilization, it is cooled to 0-6°C for temporary storage. Nutritional enhancer compounding: dissolve the minerals, plant polyphenol combination and vitamin E step by step and add them into the mixing tank. The dissolution temperature is 40-50℃, the dilution ratio of purified water is 8-10 times, and the interval between adding two adjacent substances is 3-5 minutes. Dry mix material addition: Lactobacillus casei L61, goat colostrum powder and lactoferrin are treated in a UV sterilization tunnel and then mixed with the semi-finished product through a premixer. The treatment conditions of the UV sterilization tunnel are temperature 25-35°C, humidity ≤50%, time 20-30 seconds, and the speed of the premixer is 55-60 rpm for 100-140 seconds. Spray drying: After adding the composite heat-resistant protective agent to the concentrated milk, spray drying is performed. The concentrated milk concentration is 40-50%, the stirring rate of the composite heat-resistant protective agent is 200r / min, the mixing time is 25-35min, the inlet air temperature of the spray drying is 125-135℃, the feed flow rate is 4.0-5.0mL / min, and the atomization pressure is 110-130bar; Finished product processing: The dried milk powder is cooled to 30-40℃ in a fluidized bed, and then metal detection and metering packaging are carried out in sequence. The accuracy of metal detection is Φ≥2mm.

6. The method for preparing goat milk powder as claimed in claim 5, wherein: In step 2, the stirring rate of the mineral dissolution is 300 r / min and the time is 15-20 min; the plant polyphenol combination is dissolved with ultrasound assistance, the ultrasonic power is 200 W, and the time is 5 min; the stirring rate of the vitamin E dissolution is 200 r / min and the time is 10 min.

7. The method for preparing goat milk powder as claimed in claim 5, wherein: In step 3, the fermentation temperature of Lactobacillus casei L61 is 41° C. and the fermentation time is 16 hours; the premixed materials enter a dry mixer, the speed of the dry mixer is 27-28 r / min, the mixing time is 170-190 seconds, and the coefficient of variation of the mixing uniformity is ≤5%; the purity of the lactoferrin is ≥95%.

8. The method for preparing goat milk powder as claimed in claim 5, wherein: In step 4, the nozzle diameter of the spray drying is 0.8-1.2 mm, the exhaust temperature is 80-85° C., and the negative pressure in the tower is -50 Pa; the mass ratio of glucose, skim milk, and glycerol in the composite heat-resistant protective agent is 6.03:18.98:12.

50.

9. The method for preparing goat milk powder as claimed in claim 5, wherein: The colostrum screening criteria for the acceptance of raw goat milk in step 1 are colostrum within 72 hours after birth, with a total colony count of ≤100 CFU / mL and a somatic cell count of ≤400,000 / mL.

10. The method for preparing goat milk powder according to claim 5, wherein: The sealing test condition after the metered packaging in step 5 is to maintain no bubble overflow for 30 seconds at -30kPa; the viable bacterial count of the finished milk powder stored at room temperature for 6 months is ≥1×10 8 CFU / g.

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