Fermentation type organic lactic acid bacteria formula goat milk powder and preparation method thereof

Abstract

The invention discloses fermented organic lactic acid bacteria formula goat milk powder and a preparation method thereof, relates to the field of lactic acid bacteria goat milk powder, and improves the retention rate and mixing uniformity of active ingredients by optimizing process parameters. The method comprises the following steps: after degassing, filtering and purifying raw milk, selecting pasteurization (88 DEG C / 30s) or UHT sterilization (135 DEG C / 2s) according to whether the raw milk contains active ingredients; mixing the sterilized milk with organic desalted whey powder, isomaltooligosacharide and the like, and sequentially dissolving mineral substances, vitamins and other enhancers; carrying out mechanical homogenization (18.0-21.5 MPa) on the material to preliminarily refine fat globules, and carrying out microjet homogenization (85.0-165.0 MPa) when the fat globules do not reach the standard for further treatment; carrying out gradient concentration until 45% of dry substances are obtained, and then carrying out two-stage dehydration by combining spray drying (140.0-190.0 DEG C) with freeze drying (-40 DEG C / 10Pa); and mixing the dried materials at a high speed and a low speed and packaging.

Description

Technical Field

[0001] The invention relates to the field of lactic acid bacteria goat milk powder, in particular to a fermented organic lactic acid bacteria formula goat milk powder and a preparation method thereof. Background Art

[0002] Fermented milk powder is an important food for nutritional supplementation for infants and adults. Its formula design and production process optimization have always been the research focus in this field. At present, the fermented milk powder in the existing technology mainly has the following characteristics: in terms of formula composition, traditional products mostly use a single milk source (such as pure goat milk or pure cow milk), the added prebiotics are mainly of a single type (such as oligofructose or oligoisomaltose), and the probiotics are mostly a single strain or a combination of two strains, and lack active ingredients such as HMO (human milk oligosaccharides) that simulate the sugar chain structure of breast milk; in terms of production technology, the sterilization process usually adopts a unified UHT ultra-high temperature sterilization mode, which can easily lead to the decomposition of HMO or inactivation of probiotics for products containing active ingredients; The drying process is mostly single spray drying, and long-term high-temperature treatment will significantly reduce the retention rate of active ingredients; the homogenization process generally only uses mechanical homogenization, and the uneven size of fat globules can easily cause product stratification; the mixing process is mostly simple stirring, and trace ingredients (such as nutritional enhancers) are unevenly distributed, affecting the consistency of product quality; in terms of raw material safety control, traditional products mostly use ordinary milk-derived and non-organic raw materials, which have exogenous risks such as pesticide residues and hormones, and process control mostly relies on terminal detection, and the ability to intercept microbial contamination and physical impurities in the production process is limited.

[0003] However, the above-mentioned existing technical solutions have the following technical problems: First, the formula system with a single milk source and a single component cannot simultaneously provide the synergistic effects of high-quality protein, prebiotic substrates, simulated breast milk sugar chains and multi-strain probiotics, making it difficult to comprehensively regulate the intestinal microecology and improve nutrient absorption efficiency; second, the single sterilization mode and single drying process cannot take into account both the retention of active ingredients and the long-term stability of the product, resulting in the inactivation of products containing active ingredients and the limited shelf life of products without active ingredients; third, the single homogenization and simple mixing process cannot ensure the uniformity of fat globule size and the consistency of trace component distribution, which can easily cause product stratification or quality fluctuations; fourth, the control method based on non-organic raw materials and terminal detection cannot effectively reduce exogenous risks, and the microbial contamination and physical impurities in the production process are insufficiently intercepted, affecting the food safety of the product. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a fermented organic lactic acid bacteria formula 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 present invention includes two sets of mutually nested and complementary technical solutions. The first set of technical solutions is as follows:

[0006] A fermented organic lactic acid bacteria formula goat milk powder, each ton of finished product includes the following components:

[0007] Organic whole goat milk (dry basis): 550-700kg;

[0008] Organic whole milk (dry basis): 25-175kg;

[0009] Organic desalted whey powder (D90 / D70): 100-150kg;

[0010] Organic isomaltooligosaccharide: 40-60kg;

[0011] Organic oligofructose: 40-60kg;

[0012] HMO human milk oligosaccharides: 0.5-1.0kg;

[0013] Galacto-oligosaccharide: 0.1-0.3kg;

[0014] Active lactic acid bacteria: 0.4-0.6kg;

[0015] Compound nutritional enhancer: 3.5-4.0kg;

[0016] The sum of the dry weight of the organic whole goat milk and the organic whole cow milk is 725 kg (converted into raw milk based on 11.0-12.0% milk solids), the total added amount of organic isomaltooligosaccharide and organic fructooligosaccharide is 100 kg, and the active lactic acid bacteria include at least one of the three species of Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus rhamnosus.

[0017] Specifically, the active lactic acid bacteria have the same quality of each strain and the number of viable bacteria is ≥1×10 10 CFU / g.

[0018] Specifically, the purity of the organic isomaltooligosaccharide is ≥95%, and the purity of the organic fructooligosaccharide is ≥90%.

[0019] Specifically, in the HMO human milk oligosaccharide, the total content of 2'-fucosyllactose (2'-FL) and 3-sialyllactose (3'-SL) is ≥80%, and the content of galactose oligosaccharide is ≥90%.

[0020] Specifically, the organic whole goat milk, organic whole cow milk, organic desalted whey powder, organic isomaltooligosaccharide, and organic fructooligosaccharide are all certified as organic products.

[0021] The second set of technical solutions is as follows: a method for preparing a fermented organic lactic acid bacteria formula goat milk powder, based on the fermented organic lactic acid bacteria formula goat milk powder, comprising the following steps:

[0022] (1) Pretreatment and sterilization: After degassing, filtration and purification of raw milk, the sterilization mode is selected according to whether the product contains active ingredients: the modified milk powder containing HMO / lactic acid bacteria is pasteurized (temperature 88-92℃, time 28-32s); the whole milk powder without active ingredients is UHT sterilized (temperature 133-137℃, time 1-3s); after sterilization, it is cooled to 0-6℃ for temporary storage;

[0023] (2) Standardized batching: Sterilized milk is mixed with organic desalted whey powder, organic isomaltooligosaccharide, and organic fructooligosaccharide, and the nutritional enhancers are dissolved in sequence at a batching temperature of 40-50°C. The order of dissolving the nutritional enhancers is to dissolve the minerals first, then dissolve the vitamins after an interval of ≥3 minutes, and finally dissolve the calcium carbonate.

[0024] (3) Homogenization: After the material is mechanically homogenized (pressure 18-20 MPa), when the fat globule diameter is detected to be greater than 1 μm, it is then subjected to microfluidization homogenization (pressure 100-150 MPa);

[0025] (4) Sterilization and concentration: Use a four-effect falling film evaporator for concentration, the first effect temperature is 65-75℃, the second effect is 58-68℃, the third effect is 55-65℃, the fourth effect is 50-60℃, and the discharge concentration is 40-50%;

[0026] (5) Two-stage drying: first spray drying (inlet air 150-180℃, exhaust air 80-90℃) to a moisture content of 10%, then freeze drying (temperature -45 to -35℃, vacuum degree 5-15Pa) to a moisture content ≤3%;

[0027] (6) Mixed packaging: The dried materials are pre-mixed (time 150-210s, speed 55-61r / min) and dry-mixed (time 150-210s, speed 25-30r / min), and then metal-detected (Φ≥2mm) and metered for packaging.

[0028] Specifically, the pasteurization adopts a plate-type sterilizer (heat recovery efficiency ≥ 90%), and the UHT sterilization adopts a tube-type sterilizer.

[0029] Specifically, the diameter of the fat globules after mechanical homogenization is 1-2 μm, and the diameter of the fat globules after microfluidization homogenization is 0.5-1 μm.

[0030] Specifically, the negative pressure in the spray drying tower is -60 to -40 Pa, and the freeze drying time is 2-4 hours.

[0031] Specifically, the uniformity of the premix and dry mix is controlled by the coefficient of variation of the lactose content (coefficient of variation ≤ 1%, detected by HPLC).

[0032] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0033] (1) Through the specific ratio of organic whole goat milk and cow's milk, the equal proportion of organic isomaltooligosaccharide and oligofructose, the synergistic addition of HMO human milk oligosaccharides and galacto-oligosaccharides, combined with active lactic acid bacteria, a four-dimensional nutritional system of "milk-derived protein-prebiotics-active sugar chains-probiotics" is formed. This combination is different from traditional formulas with a single milk source or a single component. It can simultaneously provide high-quality protein, prebiotic substrates that promote the proliferation of probiotics, sugar chain structures that simulate breast milk, and active bacterial communities with colonization ability, thereby more comprehensively regulating the balance of intestinal microecology and improving nutrient absorption efficiency.

[0034] (2) By selecting a differentiated sterilization mode of pasteurization (containing HMO / lactic acid bacteria) or UHT sterilization (without active ingredients) based on the presence or absence of active ingredients, combined with a two-stage drying process of spray drying (rapid dehydration to 10% moisture content) and freeze drying (low temperature to below -45°C), a synergistic process chain of "active protection-efficient dehydration" is formed. This combination is different from traditional single sterilization or drying processes. It can not only retain the activity of HMO and lactic acid bacteria through pasteurization when active ingredients are present, but also ensure long-term shelf stability through UHT sterilization when no active ingredients are present. The two-stage drying method reduces heat damage by first rapidly reducing the moisture content, and then low-temperature drying to avoid inactivation of active ingredients, ultimately achieving a dual improvement in active ingredient retention and product stability.

[0035] (3) A graded homogenization process that uses mechanical homogenization (18-20MPa) to initially refine fat globules (1-2μm in diameter) and microfluidization (100-150MPa) to secondary treat coarse fat globules (>1μm) is used. This is combined with a dual mixing process (lactose coefficient of variation ≤1%) of premixing (high speed, short time) and dry mixing (low speed, long time) to form a "fat refinement-ingredient mixing" quality control system. This combination differs from traditional single homogenization or simple mixing processes in that it can ensure uniform fat globule size (ultimately 0.5-1μm) through graded homogenization, reducing the risk of product stratification, and ensure that trace ingredients such as nutritional enhancers and prebiotics are evenly distributed in the milk powder through dual mixing, thereby improving product quality consistency.

[0036] (IV) Through organic certification (compliant with CNCA-N-009:2021) of organic whole goat milk, cow milk, desalted whey powder, oligomalto-oligosaccharides, oligofructose and other raw materials, combined with pre-treatment sterilization (pasteurization / UHT), metal detection (Φ ≥ 2mm) and other process controls, a full-chain quality assurance system of "raw material compliance-process safety" is formed. This combination is different from traditional non-organic or terminal-only testing processes. It can not only reduce exogenous risks such as pesticide residues and hormones through organic raw materials, but also kill pathogens through process sterilization and intercept physical impurities through metal detection, ultimately improving the product's edible safety and consumer trust. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The present invention is a schematic flow chart of the preparation method of the fermented organic lactic acid bacteria formula goat milk powder. DETAILED DESCRIPTION

[0038] 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.

[0039] Application Overview

[0040] Fermented milk powder is an important category of nutritional fortified food. The industry's conventional approach to its formula design and production process is mainly reflected in the following: in terms of formula composition, a single milk source (such as pure goat's milk or pure cow's milk) is mostly used, the added prebiotics are mainly of a single type (such as only oligofructose or oligoisomaltose), probiotics are mostly single strains or a combination of two strains, and usually do not contain active ingredients such as HMO (human milk oligosaccharides) that simulate the sugar chain structure of breast milk; in the sterilization process, a unified UHT ultra-high temperature sterilization mode is generally adopted to take into account both sterilization effect and production efficiency; the drying process mostly relies on a single spray drying process, and moisture content control is achieved through high-temperature rapid dehydration; the homogenization process usually only uses mechanical homogenization equipment for a single treatment to reduce equipment costs; the mixing process is mostly simple stirring, and the ingredients are dispersed through short-term low-speed mixing; in terms of raw material selection, ordinary milk sources and non-organic raw materials are mostly used, and product safety is controlled through terminal testing (such as microbial testing and metal foreign body screening).

[0041] However, the above conventional solutions have significant shortcomings: the formula system of a single milk source and a single component makes it difficult to build a synergistic nutritional network of "milk protein-prebiotics-active sugar chains-probiotics", resulting in limited regulatory effects on intestinal microecology and insignificant improvement in nutrient absorption efficiency; although the unified UHT sterilization mode can ensure the sterilization effect, it will destroy the biological activity of active ingredients such as HMO and probiotics, and if the sterilization temperature is lowered for products containing active ingredients, it may lead to substandard microbial control; the high temperature and long time treatment of a single spray drying will significantly reduce the retention rate of active ingredients and affect product function; single mechanical homogenization is difficult to control the uniformity of fat globule size, which can easily cause problems such as product stratification and rough taste; simple mixing processes cannot ensure the uniform distribution of trace ingredients (such as nutritional enhancers and prebiotics) in milk powder, resulting in fluctuations in product quality; the control method based on ordinary raw materials and terminal testing is difficult to effectively reduce exogenous risks such as pesticide residues and hormones, and has limited interception capabilities for problems such as microbial contamination and physical impurities during the production process, affecting product safety.

[0042] Comprehensive description

[0043] The present invention relates to a fermented organic lactic acid bacteria formula goat milk powder and its preparation method. Through formula optimization and process innovation, the invention aims to provide a milk powder product that retains highly active nutrients, regulates the intestinal microbiome, and is safe for consumption. The following describes the specific technical solution in detail.

[0044] 1. Product formula composition

[0045] The fermented organic lactic acid bacteria formula goat milk powder of the present invention comprises the following components per ton of finished product:

[0046] Organic whole goat milk (dry basis): 550-700kg;

[0047] Organic whole milk (on a dry basis): 25-175kg;

[0048] Organic desalted whey powder (D90 / D70): 100-150kg;

[0049] Organic isomaltooligosaccharide (purity ≥ 95%): 40-60kg;

[0050] Organic oligofructose (purity ≥90%): 40-60kg;

[0051] HMO human milk oligosaccharides (2'-fucosyllactose and 3-sialyllactose total content ≥ 80%): 0.5-1.0kg;

[0052] Galacto-oligosaccharide (content ≥90%): 0.1-0.3kg;

[0053] Active lactic acid bacteria (including three strains of Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus rhamnosus, each strain has the same quality, and the number of viable bacteria is ≥1×10 10 CFU / g): 0.4-0.6kg;

[0054] Compound nutritional enhancers (including minerals, vitamins and calcium carbonate, etc.): 3.5-4.0kg.

[0055] Among them, the sum of the dry weight of organic whole goat milk and organic whole cow's milk is fixed at 725kg (the amount of raw milk is converted at 11.0-12.0% milk solids) to balance the mild taste of goat milk and the protein complementarity of cow's milk; the total addition amount of organic oligomaltodextrose and organic oligofructose is 100kg to form a prebiotic synergistic effect; all organic raw materials (organic whole goat milk, organic whole cow's milk, organic desalted whey powder, organic oligomaltodextrose, organic oligofructose) have passed the national organic product certification (in compliance with CNCA-N-009:2021 standards) to ensure that the raw materials are free of exogenous pollution such as pesticide residues and hormones.

[0056] 2. Preparation Method

[0057] The preparation method of the present invention includes six core steps: pretreatment and sterilization, standardized batching, homogenization, sterilization and concentration, two-stage drying, and mixed packaging. The specific operations are as follows:

[0058] 1. Pretreatment and sterilization

[0059] After degassing, filtration, and milk purification, the raw milk (a mixture of organic whole goat milk and organic whole cow milk) is sterilized in the following ways depending on whether the product contains active ingredients:

[0060] For formula milk powder containing HMO human milk oligosaccharides or active lactic acid bacteria, a pasteurization process is adopted: a plate-type pasteurizer (heat recovery efficiency ≥ 90%) is used, the pasteurization temperature is controlled at 88-92°C, and the time is 28-32 seconds, to balance the killing of pathogens (killing rate of Salmonella and Staphylococcus aureus ≥ 99.99%) and the retention of active ingredients;

[0061] For whole milk powder without active ingredients, UHT sterilization is used: using a tubular sterilizer, the sterilization temperature is controlled at 133-137°C for 1-3 seconds to ensure complete inactivation of microorganisms. The sterilized material is then cooled to 0-6°C for temporary storage to prevent secondary microbial growth.

[0062] 2. Standardized ingredients

[0063] Mix the sterilized milk with organic desalted whey powder, organic isomaltooligosaccharide, and organic fructooligosaccharide at a temperature of 40-50°C. The compounded nutritional supplements must be dissolved in a specific order: first, dissolve the minerals (such as iron and zinc), then dissolve the vitamins (such as vitamin A and vitamin D) after a 3-minute interval, and finally dissolve the calcium carbonate to avoid precipitation or stratification due to differences in solubility of different nutrients.

[0064] 3. Homogenization

[0065] The material is processed by a mechanical homogenizer with a controlled homogenization pressure of 18-20 MPa to initially refine the fat globules to a diameter of 1-2 μm. The diameter of the fat globules is detected by an online laser particle size analyzer. If the diameter of the fat globules is greater than 1 μm, the material is further processed using a microfluidizer (pressure 100-150 MPa) to ultimately control the diameter of the fat globules to 0.5-1 μm to improve the homogeneity and stability of the product.

[0066] 4. Sterilization concentration

[0067] A four-effect falling film evaporator is used for concentration, and the temperature of each effect is controlled in sequence: 65-75°C for the first effect, 58-68°C for the second effect, 55-65°C for the third effect, and 50-60°C for the fourth effect. The loss of heat-sensitive components is reduced by gradient cooling, and the final discharge concentration is controlled at 40-50% (based on dry matter).

[0068] 5. Two-stage drying

[0069] The drying process is divided into two stages: spray drying and freeze drying:

[0070] Spray drying: Control the inlet air temperature at 150-180°C, the exhaust air temperature at 80-90°C, and the negative pressure in the tower at -60 to -40Pa to quickly reduce the moisture content of the material to 10%, reducing the damage of high temperature to the active ingredients;

[0071] Freeze drying: Place the spray-dried material in a freeze dryer, control the temperature to -45 to -35°C, and the vacuum degree to 5-15Pa, and dry it for 2-4 hours, ultimately reducing the moisture content to ≤3%, thereby maximizing the retention of the biological activity of HMO human milk oligosaccharides and active lactic acid bacteria.

[0072] 6. Mixed packaging

[0073] The dried materials need to be mixed by pre-mixing and dry mixing:

[0074] Premixing stage: Use a high-speed mixer, control the speed to 55-61r / min, and the mixing time to 150-210 seconds to preliminarily disperse the materials;

[0075] Dry mixing: Switch to a low-speed mixer, controlling the speed to 25-30 r / min and the mixing time to 150-210 seconds to ensure uniform distribution of trace ingredients (such as HMO and active lactic acid bacteria) (using HPLC to test the coefficient of variation of lactose content to ≤1% to verify mixing uniformity). After mixing, the material is screened with a metal detector (capable of detecting metal impurities Φ ≥ 2mm) and finally metered and packaged as the finished product.

[0076] Through the above-mentioned formula design and process control, the present invention can stably prepare fermented organic lactic acid bacteria formula goat milk powder with high active ingredient retention rate, uniform nutrient distribution and good food safety, thereby meeting consumers' demand for high-quality nutritious food.

[0077] To verify the impact of key parameters in the preparation process of the present invention on the core performance of fermented organic lactic acid bacteria formula goat milk powder and clarify the practical significance of the parameter range, the following experiment was designed based on GB 19644-2010 "National Food Safety Standard Milk Powder" (Lactic Acid Bacteria Milk Powder) and GB 5413.18-2010 "National Food Safety Standard Infant and Young Child Food and Dairy Products Determination of Vitamins A, D, and E". The experiment used the number of viable lactic acid bacteria (reflecting the retention of active ingredients), the retention rate of HMO human milk oligosaccharides (reflecting the stability of heat-sensitive ingredients), and the lactose coefficient of variation (reflecting the uniformity of mixing; the smaller the coefficient of variation, the more uniform the mixing) as core performance indicators. Mechanical homogenization pressure (MPa), microjet homogenization pressure (MPa), and spray drying inlet temperature (°C) were selected as variables. By comparing the product performance under different parameter combinations, the rationality of the parameter range was verified.

[0078] Experimental design

[0079] Experimental variables: mechanical homogenization pressure (A), microfluidization homogenization pressure (B), spray drying inlet air temperature (C).

[0080] Experimental group setup: A total of 10 groups, of which G1-G5 were conventional groups (variables within process limits), G6-G9 were out-of-range controls (variables outside the limits), and G10 was a blank control group (using existing technology: single mechanical homogenization at 15 MPa, no jet homogenization, spray drying at 200°C, mixing time 200 seconds). Except for the variables, all other experimental groups were strictly consistent in terms of material composition, proportions, and environmental parameters (such as batching temperature of 45°C, concentrate concentration of 45%, freeze-drying temperature of -40°C, etc.).

[0081] Test method:

[0082] Viable lactic acid bacteria count: according to GB 4789.35-2016 "National Food Safety Standard - Microbiological Examination of Foods - Lactic Acid Bacteria", using the MRS agar plate count method, the result is expressed in CFU / g;

[0083] HMO retention rate: HMO content (calculated as the total content of 2'-fucosyllactose and 3-sialyllactose) was determined by HPLC according to the derivatization method in GB 5009.284-2021 "National Food Safety Standard - Determination of Lactoferrin and Lactoperoxidase in Foods". Retention rate = (HMO content in finished product / theoretical addition amount) × 100%;

[0084] Lactose coefficient of variation: According to GB 5413.5-2010 "National Food Safety Standard - Determination of Lactose and Sucrose in Infant and Young Children's Food and Dairy Products", the lactose content of 10 random sampling points was tested and the coefficient of variation (CV = standard deviation / mean value × 100%) was calculated.

[0085] Weighted scoring rule: Comprehensive score = (viable cell count score × 0.4) + (HMO retention rate score × 0.3) + (lactose coefficient of variation score × 0.3).

[0086] Viable bacteria count score: based on the national standard limit of 1×10 6 CFU / g is the basis, and each increase of 1×10 6 CFU / g is scored as 1 point (e.g. 8.2×10 6 CFU / g scored 8.2 points);

[0087] HMO retention rate score: Based on the theoretical maximum of 85%, 0.5 points will be deducted for every 1% decrease in the actual retention rate (e.g., 78.6% is 78.6 - (85 - 78.6) × 0.5 = 75.4 points);

[0088] Lactose coefficient of variation score: Based on the target value of 1%, 1 point will be deducted for every 0.1% increase in the coefficient of variation (for example, 0.65% is 100-(0.65-1)×10×1=103.5 points, but the upper limit is 100 points).

[0089] The experimental results are recorded and analyzed as follows

[0090] Table 1. Experimental group parameters and results

[0091]

[0092]

[0093] Result Analysis

[0094] From the experimental data we can see that:

[0095] The viable lactic acid bacteria counts in the conventional groups (G1-G5) were 8.2-12.5×10 6CFU / g), HMO retention rate (78.6-85.2%) and lactose coefficient of variation (0.65-0.92%) were significantly better than those in the out-of-range control group (G6-G9: viable bacteria count 5.1-7.8×10 6 CFU / g, HMO retention rate 65.3-75.1%, coefficient of variation 1.05-1.42%) and blank control group (G10: 3.2×10 6 CFU / g, 58.7%, 1.89%), which verified the rationality of the limited range of process parameters;

[0096] Group G3, which had the highest overall score (93.8 points), achieved the upper limit of the parameter combination (A = 20.0 MPa, B = 150.0 MPa, and C = 180.0°C). This indicates that, within the specified range, higher homogenization pressure and spray temperature may increase the risk of thermal damage. However, the synergistic effect of fine-tuning microfluidization and two-stage drying can achieve an optimal balance between active ingredient retention and mixing uniformity.

[0097] In the out-of-range control group, the HMO retention rate decreased (75.1%) in group G7 (A = 21.0 MPa, B = 160.0 MPa, C = 185.0°C) due to excessive pressure and temperature, while the viable bacterial count and mixing uniformity were significantly reduced in group G6 (A = 17.0 MPa, B = 90.0 MPa, C = 145.0°C) due to insufficient pressure and temperature, further demonstrating the critical significance of the parameter range;

[0098] The blank control group (G10) had the worst active ingredient retention rate and mixing uniformity due to the use of a single homogenization and high-temperature drying process, which confirmed the innovativeness of the process of the present invention.

[0099] The above experimental results show that the parameter limitations of the present invention on mechanical homogenization pressure, microjet homogenization pressure and spray drying inlet temperature can effectively balance active ingredient retention, mixing uniformity and product stability, and have clear practical application value.

[0100] The experimental data shows that the comprehensive scores of the conventional groups (G1-G5) were significantly higher than those of the out-of-range control group (G6-G9) and the blank control group (G10). This trend can be traced back to molecular interactions and physicochemical mechanisms. The following is a detailed analysis combining key performance indicators and variable parameters:

[0101] 1. Molecular protection mechanism of viable lactic acid bacteria

[0102] The survival of lactic acid bacteria depends on the integrity of the cell membrane and the maintenance of intracellular enzyme activity. Under a limited range of mechanical homogenization pressure (18-20MPa) and microfluidization homogenization pressure (100-150MPa), fat globules are refined to 0.5-1μm (diameter). The milk proteins (such as β-casein and whey protein) on their surface form a "protective shell" with the phospholipid bilayer of the lactic acid bacteria cell membrane through hydrophobic interactions. The α-helical structure of the milk protein and the fatty acid chains of the membrane phospholipids interact with each other through van der Waals forces, reducing the tensile damage to the cell membrane caused by water evaporation during the subsequent drying process.

[0103] When the homogenization pressure is lower than the specified range (e.g. A = 17.0 MPa, B = 90.0 MPa for G6 and G8), the fat globule diameter is greater than 1 μm, the amount of milk protein adsorbed on the surface is reduced, and a dense protective layer cannot be formed. At this time, the high temperature of spray drying (140-145°C) will accelerate water evaporation, causing the cell membrane to rupture due to the sudden change in osmotic pressure, inactivating key enzymes such as intracellular lactate dehydrogenase, and significantly reducing the number of viable bacteria (5.1-5.6×10 6 CFU / g).

[0104] If the homogenization pressure exceeds the specified range (e.g. A = 21.0 MPa, B = 160.0 MPa for G7 and G9), the excessive shear force will directly destroy the phospholipid bilayer of the lactic acid bacteria cell membrane, resulting in the K + Mg 2+ Plasma overflows and intracellular enzymes denature due to ion concentration imbalance. Although the fat globules are further refined (<0.5μm), the surface charge (ζ potential) of the over-broken fat globules increases, which produces electrostatic repulsion with the negative charge on the surface of the lactic acid bacteria membrane, weakening the protective effect. The number of viable bacteria is only 7.8-6.3×10 6 CFU / g.

[0105] 2. Stability of Thermosensitive Molecules with HMO Retention Rate

[0106] The core structure of HMO (such as 2'-fucosyllactose) is a galactose-glucose-fucose trisaccharide chain, and its glycosidic bond (-O-) is highly sensitive to temperature. Within a limited range of spray drying inlet air temperatures (150-180°C), a two-stage drying process (spraying + freezing) inhibits the thermal degradation of HMO through the synergistic effect of "rapid dehydration and low-temperature solidification": the spray drying stage (inlet air 150-180°C) quickly reduces the moisture content of the material to 10%, reducing the contact time of HMO with water. The freeze drying stage (-45 to -35°C) uses sublimation dehydration to avoid hydrolysis in the presence of liquid water (H2O attacks the CO bond of the glycosidic bond), resulting in an HMO retention rate of 78.6-85.2%.

[0107] When the spray temperature is lower than the specified range (e.g. C = 140-145°C for G6 and G8), the spray drying efficiency is reduced, the residence time of the material in the high temperature zone is prolonged (> 120 seconds), and the glycosidic bond of HMO is separated from H in the liquid water environment. + Nucleophilic substitution reaction occurs, resulting in the shedding of the fucose group (2'-fucosyllactose→lactose), with a retention rate of only 65.3-68.4%.

[0108] If the spray temperature exceeds the specified range (e.g., C = 185-190°C for G7 and G9), the hydroxyl groups (-OH) in the HMO molecules and the aldehyde groups (-CHO) of lactose undergo a Maillard reaction at high temperatures to form brown-brown melanoidin polymers, destroying the sugar chain structure of the HMO and reducing the retention rate to 72.9-75.1%.

[0109] 3. Molecular dispersion mechanism of lactose coefficient of variation

[0110] The uniform distribution of lactose is closely related to the stability of the protein-lactose complex on the surface of the fat globules. Under homogenization pressures within a defined range (A = 18-20 MPa, B = 100-150 MPa), milk proteins (such as κ-casein) on the surface of the fat globules bind to the hydroxyl groups (-OH) of lactose through hydrogen bonds (-NH…O-), forming "protein-lactose" complexes (particle size approximately 200-300 nm). These complexes are uniformly dispersed in the milk powder matrix through electrostatic repulsion (zeta potential -25 to -30 mV), with a lactose coefficient of variation of only 0.65-0.92%.

[0111] When the homogenization pressure is insufficient (such as G6, G8), the fat globule diameter is greater than 1 μm, and the amount of milk protein adsorbed on the surface is reduced (less than 0.5 mg / m 2 ), lactose cannot be fully combined with protein and is easily settled due to gravity, forming a local high concentration area (coefficient of variation 1.05-1.12%).

[0112] If the homogenization pressure is too high (such as G7, G9), the fat globules are overly broken (<0.5μm), the surface charge increases (ζ potential <-35mV), the hydrogen bonds between lactose and protein are destroyed by electrostatic repulsion, and the lactose molecules diffuse randomly due to Brownian motion, resulting in uneven distribution (coefficient of variation 1.28-1.42%).

[0113] 4. Molecular synergy of comprehensive score

[0114] Group G3 (A = 20.0 MPa, B = 150.0 MPa, C = 180.0°C) achieved the highest overall score (93.8 points). The key to this score lies in the parameter combination that achieved molecular synergy among "protective shell strength, thermal stability, and dispersibility":

[0115] The highest homogenization pressure (A = 20.0 MPa, B = 150.0 MPa) makes the fat globule diameter the smallest (0.5 μm) and the surface milk protein adsorption the largest (0.8 mg / m 2 ), the protective shell of lactic acid bacteria is the densest;

[0116] The maximum spray temperature (C = 180.0°C) combined with freeze drying not only quickly reduces the moisture content (avoids HMO hydrolysis) but also inhibits the Maillard reaction through low-temperature solidification;

[0117] The dense "protein-lactose" complex has the best dispersion (coefficient of variation 0.65%) due to its moderate zeta potential (-28 mV).

[0118] The G10 blank control group had the worst overall performance due to the lack of microfluidization homogenization (no B parameter) and two-stage drying (only high-temperature spraying), fat globule diameter > 2 μm (no protein protective shell), severe HMO hydrolysis (retention rate 58.7%), and lactose gravity sedimentation resulting in a coefficient of variation as high as 1.89%.

[0119] In summary, the parameter limitations of homogenization pressure and drying temperature in this process are essentially achieved by regulating the intermolecular interactions (van der Waals forces, hydrogen bonds, and electrostatic repulsion) between fat globules, proteins, lactose, and lactic acid bacteria, thereby achieving a balance between protecting active ingredients, stabilizing functional molecular structures, and improving dispersion uniformity, thereby verifying the practical significance of the parameter range.

[0120] Example

[0121] Example 1

[0122] Preparation method of fermented organic lactic acid bacteria formula goat milk powder (corresponding to experimental group G1):

[0123] Pretreatment and sterilization: 550 kg of organic whole goat milk (dry basis, milk solids content 11.5%) and 175 kg of organic whole cow milk (dry basis, milk solids content 11.8%) were mixed. After degassing, filtration through a double filter (pore size 0.5 μm), and centrifugation (speed 6000 r / min), pasteurization was performed using a plate-type sterilizer (heat recovery efficiency 92%) at a controlled temperature of 88°C for 30 seconds to kill Salmonella and Staphylococcus aureus (kill rate ≥ 99.99%). After sterilization, the material was cooled to 5°C for temporary storage.

[0124] Standardized ingredients: Add sterilized mixed milk, 125kg of organic desalted whey powder (D90 type), 50kg of organic isomaltooligosaccharide (95% purity), and 50kg of organic fructooligosaccharide (90% purity) to the batching tank and control the batching temperature at 45°C. Dissolve the compound nutritional enhancers in sequence: first add 2.0kg of minerals (including ferrous sulfate and zinc gluconate), stir for 3 minutes, then add 1.0kg of vitamins (including vitamin A and vitamin D3), and then stir for another 3 minutes before adding 1.0kg of calcium carbonate, ensuring no precipitation or stratification.

[0125] Homogenization treatment: The material is processed by a mechanical homogenizer with a control pressure of 18.0 MPa to initially refine the fat globules to a diameter of 1.2 μm. After detection by an online laser particle size analyzer, the material is further processed by a microfluidizer with a control pressure of 100.0 MPa to ultimately control the fat globule diameter to 0.9 μm.

[0126] Sterilization and concentration: A four-effect falling film evaporator is used for concentration, with the first effect temperature at 68°C, the second effect temperature at 62°C, the third effect temperature at 58°C, and the fourth effect temperature at 52°C. Gradient cooling is used to reduce the loss of heat-sensitive components, and the final discharge concentration is controlled at 45% (dry matter basis).

[0127] Two-stage drying:

[0128] Spray drying: Control the inlet air temperature at 150.0°C, the exhaust air temperature at 82°C, and the negative pressure in the tower at -50Pa to quickly reduce the moisture content of the material to 10%;

[0129] Freeze drying: Place the spray-dried material in a freeze dryer, control the temperature at -40°C and the vacuum degree at 10 Pa, and dry it for 3 hours until the final moisture content drops to 2.8%.

[0130] Mixing and Packaging: The dried material is first mixed in a high-speed mixer (58 rpm) for 180 seconds, then switched to a low-speed mixer (28 rpm) for another 180 seconds to ensure uniform distribution of HMO and active lactic acid bacteria (lactose coefficient of variation 0.92%). After mixing, the mixture is screened with a metal detector (detecting metal impurities up to 2 mm in diameter) and packaged as finished product.

[0131] Example 2

[0132] Preparation method of fermented organic lactic acid bacteria formula goat milk powder (corresponding to experimental group G2):

[0133] The steps are exactly the same as in Example 1, except for adjusting the following parameters:

[0134] Homogenization: mechanical homogenization pressure 19.0 MPa, microfluidization pressure 120.0 MPa (fat globule diameter 0.8 μm);

[0135] Two-stage drying: spray drying inlet air temperature 160.0℃ (exhaust air temperature 85℃).

[0136] Example 3

[0137] Preparation method of fermented organic lactic acid bacteria formula goat milk powder (corresponding to experimental group G3):

[0138] The steps are exactly the same as in Example 1, except for adjusting the following parameters:

[0139] Homogenization: mechanical homogenization pressure 20.0 MPa, microfluidization homogenization pressure 150.0 MPa (fat globule diameter 0.5 μm);

[0140] Two-stage drying: spray drying air inlet temperature 180.0℃ (exhaust air temperature 88℃).

[0141] Example 4

[0142] Preparation method of fermented organic lactic acid bacteria formula goat milk powder (corresponding to experimental group G4):

[0143] The steps are exactly the same as in Example 1, except for adjusting the following parameters:

[0144] Homogenization: mechanical homogenization pressure 19.0 MPa, microfluidization pressure 130.0 MPa (fat globule diameter 0.7 μm);

[0145] Two-stage drying: spray drying inlet air temperature 170.0℃ (exhaust air temperature 86℃).

[0146] Example 5

[0147] Preparation method of fermented organic lactic acid bacteria formula goat milk powder (corresponding to experimental group G5):

[0148] The steps are exactly the same as in Example 1, except for adjusting the following parameters:

[0149] Homogenization: mechanical homogenization pressure 18.5 MPa, microfluidization pressure 110.0 MPa (fat globule diameter 0.8 μm);

[0150] Two-stage drying: spray drying inlet air temperature 165.0℃ (exhaust air temperature 84℃).

[0151] Example 6

[0152] Preparation method of fermented organic lactic acid bacteria formula goat milk powder (corresponding to experimental group G6):

[0153] The steps are exactly the same as in Example 1, except for adjusting the following parameters:

[0154] Homogenization: Mechanical homogenization pressure 17.0MPa (extraordinary range), microfluidization pressure 90.0MPa (extraordinary range, fat globule diameter 1.3μm);

[0155] Two-stage drying: spray drying air inlet temperature is 145.0℃ (exceeding the normal range, exhaust air temperature is 80℃).

[0156] Example 7

[0157] Preparation method of fermented organic lactic acid bacteria formula goat milk powder (corresponding to experimental group G7):

[0158] The steps are exactly the same as in Example 1, except for adjusting the following parameters:

[0159] Homogenization: Mechanical homogenization pressure 21.0MPa (extraordinary range), microfluidization homogenization pressure 160.0MPa (extraordinary range, fat globule diameter 0.4μm);

[0160] Two-stage drying: spray drying air inlet temperature is 185.0℃ (exceeding the normal range, exhaust air temperature is 90℃).

[0161] Example 8

[0162] Preparation method of fermented organic lactic acid bacteria formula goat milk powder (corresponding to experimental group G8):

[0163] The steps are exactly the same as in Example 1, except for adjusting the following parameters:

[0164] Homogenization: Mechanical homogenization pressure 17.5MPa (extraordinary range), microfluidic homogenization pressure 85.0MPa (extraordinary range, fat globule diameter 1.2μm);

[0165] Two-stage drying: Spray drying air inlet temperature is 140.0℃ (exceeding the normal range, exhaust air temperature is 78℃).

[0166] Example 9

[0167] Preparation method of fermented organic lactic acid bacteria formula goat milk powder (corresponding to experimental group G9):

[0168] The steps are exactly the same as in Example 1, except for adjusting the following parameters:

[0169] Homogenization: Mechanical homogenization pressure 21.5MPa (extraordinary range), microfluidization homogenization pressure 165.0MPa (extraordinary range, fat globule diameter 0.3μm);

[0170] Two-stage drying: spray drying air inlet temperature is 190.0℃ (exceeding the normal range, exhaust air temperature is 92℃).

[0171] Example 10 (blank control group)

[0172] Preparation method of fermented organic lactic acid bacteria formula goat milk powder (corresponding to experimental group G10):

[0173] Pretreatment and sterilization: 550 kg (dry basis) of organic whole goat milk and 175 kg (dry basis) of organic whole cow milk were mixed. After degassing, filtration, and milk purification, the mixture was sterilized using the existing UHT process (existing technology): a tubular sterilizer was used at a controlled temperature of 135°C for 2 seconds to kill microorganisms. After sterilization, the mixture was cooled to 5°C for temporary storage.

[0174] Standardized ingredients: the same as in Example 1.

[0175] Homogenization (existing technology): Only a mechanical homogenizer was used for processing, the mechanical homogenization pressure was controlled at 15.0 MPa (without the jet homogenization step), and the fat globule diameter was 2.1 μm.

[0176] Sterilization and concentration: same as in Example 1.

[0177] Drying process (existing technology): only single spray drying is used, the inlet air temperature is controlled at 200°C and the exhaust air temperature is controlled at 95°C, and the moisture content of the material is directly reduced to 2.8% (without freeze drying).

[0178] Mixed packaging (existing technology): using only a high-speed mixer (rotation speed 58 r / min) for 200 seconds (no low-speed mixing), the lactose variation coefficient was 1.89%.

[0179] The remaining steps are consistent with those in Example 1.

[0180] Specific working process

[0181] After degassing, filtering, and purifying, the raw milk is sterilized using a selected sterilization method depending on whether it contains active ingredients. Active ingredients are pasteurized using a plate-type sterilizer for rapid sterilization at elevated temperatures before being cooled and temporarily stored. Inactive ingredients are UHT sterilized using a tubular sterilizer for instantaneous high-temperature sterilization before being cooled and temporarily stored. The pasteurized milk is then mixed with organic demineralized whey powder, organic isomaltooligosaccharides, and organic fructooligosaccharides. Nutrient enhancers are dissolved in the order of minerals, vitamins, and calcium carbonate. The mixture is initially homogenized in a mechanical homogenizer to refine the fat globules. If the globule diameter does not meet the standard, it is further processed in a microfluidizer to reduce it to the target range. The homogenized material then enters a four-effect falling film evaporator for concentration to the target dry matter concentration using a gradient cooling process. The concentrated material is spray-dried to rapidly reduce its moisture content before being transferred to a freeze dryer for further dehydration through low-temperature vacuum sublimation to the final moisture content. The dried materials are pre-mixed in a high-speed mixer and dry-mixed in a low-speed mixer in turn to ensure uniform distribution of ingredients. After screening by a metal detector, they are measured and packaged as finished products.

[0182] 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. A fermented organic lactic acid bacteria formula goat milk powder, characterized in that: Each ton of finished product includes the following components: Organic whole goat milk (dry basis): 550-700kg; Organic whole milk (on a dry basis): 25-175kg; Organic desalted whey powder (D90 / D70): 100-150kg; Organic isomaltooligosaccharide: 40-60kg; Organic oligofructose: 40-60kg; HMO human milk oligosaccharides: 0.5-1.0kg; Galacto-oligosaccharide: 0.1-0.3kg; Active lactic acid bacteria: 0.4-0.6kg; Compound nutritional enhancer: 3.5-4.0kg; The sum of the dry weight of the organic whole goat milk and the organic whole cow milk is 725 kg (converted into raw milk based on 11.0-12.0% milk solids), the total added amount of organic isomaltooligosaccharide and organic fructooligosaccharide is 100 kg, and the active lactic acid bacteria include at least one of the three species of Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus rhamnosus.

2. The fermented organic lactic acid bacteria formula goat milk powder according to claim 1, characterized in that: The active lactic acid bacteria contained in the present invention have the same quality of each strain and the number of viable bacteria is ≥1×10 10 CFU / g.

3. The fermented organic lactic acid bacteria formula goat milk powder according to claim 1, characterized in that: The purity of the organic isomaltooligosaccharide is ≥95%, and the purity of the organic fructooligosaccharide is ≥90%.

4. The fermented organic lactic acid bacteria formula goat milk powder according to claim 1, characterized in that: In the HMO human milk oligosaccharide, the total content of 2'-fucosyllactose (2'-FL) and 3-sialyllactose (3'-SL) is ≥80%, and the content of galactose oligosaccharide is ≥90%.

5. The fermented organic lactic acid bacteria formula goat milk powder according to claim 1, characterized in that: The organic whole goat milk, organic whole cow milk, organic desalted whey powder, organic isomaltooligosaccharide and organic fructooligosaccharide are all certified as organic products.

6. A method for preparing a fermented organic lactic acid bacteria formula goat milk powder, based on the fermented organic lactic acid bacteria formula goat milk powder according to claims 1-5, characterized in that: The following steps are involved: (1) Pretreatment and sterilization: After degassing, filtration and purification of raw milk, the sterilization mode is selected according to whether the product contains active ingredients: the modified milk powder containing HMO / lactic acid bacteria is pasteurized (temperature 88-92℃, time 28-32s); the whole milk powder without active ingredients is UHT sterilized (temperature 133-137℃, time 1-3s); after sterilization, it is cooled to 0-6℃ for temporary storage; (2) Standardized batching: Sterilized milk is mixed with organic desalted whey powder, organic isomaltooligosaccharide, and organic fructooligosaccharide, and the nutritional enhancers are dissolved in sequence at a batching temperature of 40-50°C. The order of dissolving the nutritional enhancers is to dissolve the minerals first, then dissolve the vitamins after an interval of ≥3 minutes, and finally dissolve the calcium carbonate. (3) Homogenization: After the material is mechanically homogenized (pressure 18-20 MPa), when the fat globule diameter is detected to be greater than 1 μm, it is then subjected to microfluidization homogenization (pressure 100-150 MPa); (4) Sterilization and concentration: Use a four-effect falling film evaporator for concentration, the first effect temperature is 65-75℃, the second effect is 58-68℃, the third effect is 55-65℃, the fourth effect is 50-60℃, and the discharge concentration is 40-50%; (5) Two-stage drying: first spray drying (inlet air 150-180℃, exhaust air 80-90℃) to a moisture content of 10%, then freeze drying (temperature -45 to -35℃, vacuum degree 5-15Pa) to a moisture content ≤3%; (6) Mixed packaging: The dried materials are pre-mixed (time 150-210s, speed 55-61r / min) and dry-mixed (time 150-210s, speed 25-30r / min), and then metal-detected (Φ≥2mm) and metered for packaging.

7. The method for preparing the fermented organic lactic acid bacteria formula goat milk powder according to claim 6, wherein: The pasteurization adopts a plate-type sterilizer (heat recovery efficiency ≥ 90%), and the UHT sterilization adopts a tube-type sterilizer.

8. The method for preparing the fermented organic lactic acid bacteria formula goat milk powder according to claim 6, wherein: The diameter of the fat globules after mechanical homogenization is 1-2 μm, and the diameter of the fat globules after microfluidization homogenization is 0.5-1 μm.

9. The method for preparing the fermented organic lactic acid bacteria formula goat milk powder according to claim 6, wherein: The negative pressure in the spray drying tower is -60 to -40 Pa, and the freeze drying time is 2-4 hours.

10. The method for preparing the fermented organic lactic acid bacteria formula goat milk powder according to claim 6, wherein: The uniformity of the premix and dry mix is controlled by the coefficient of variation of the lactose content (coefficient of variation ≤ 1%, detected by HPLC).

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