Method for preparing formula milk powder

Abstract

A method for preparing a formula milk powder. The method comprises: a step of mixing a base milk raw material liquid, a skimmed milk raw material liquid, a desalted whey raw material liquid and optionally other permissible non-temperature sensitive components; and a step of spray drying the resulting mixture, wherein in the mixing step, the base milk raw material liquid is a pasteurized emulsion directly derived from animals, the skimmed milk raw material liquid is an emulsion obtained by centrifugal degreasing of animal milk, the desalted whey raw material liquid is an emulsion obtained by whey separation and whey desalination of animal milk, and both whey separation and whey desalination are performed by membrane separation.

Description

Method for preparing a formula milk powder TECHNICAL FIELD

[0001] The present application belongs to the technical field of food, and relates to a method for preparing a formula milk powder, more particularly to a method for preparing a formula milk powder for infants and young children with excellent freshness and reconstitution. BACKGROUND

[0002] Breast milk is an ideal food source for ensuring the growth and development of infants and young children. The World Health Organization (WHO) recommends that infants implement exclusive breastfeeding for the first 6 months after birth, but due to various realistic factors, some infants cannot obtain exclusive breastfeeding or need to terminate breastfeeding prematurely. In order to ensure the normal nutritional needs of infants and young children, formula milk powder becomes the only source of nutrition for breast milk replacement. However, during the production process of infant formula milk powder, multiple stages of high-intensity heat treatment are required to achieve sterilization requirements. This processing method, while ensuring food safety, may also have potential effects on the nutritional value and safety of the product.

[0003] In the heat treatment process of infant formula milk powder, the Maillard reaction is one of the most representative chemical changes. The essence of this reaction is a non-enzymatic browning reaction between the carbonyl group of reducing sugars (such as lactose, galactose) and the amino group of amino acids (such as lysine, arginine). Since cow's milk is rich in lactose, galactose, and various proteins and amino acids, it is extremely easy to trigger such reactions during processing. In the primary reaction stage, the epsilon-amino group of lysine combines with reducing sugars to form lactulose-lysine complexes, resulting in a significant reduction in the bioavailability of lysine. As the reaction progresses, these complexes are further oxidized to form carboxymethyl lysine (also known as furan amino acid), which is referred to as "locked lysine". It is worth noting that the content of furan amino acid has become an internationally recognized quantitative indicator of heat treatment intensity and the progress of the Maillard reaction in dairy products. Studies have shown that the amount of Maillard reaction products (MRPs) generated in dairy products is positively correlated with heat treatment parameters, specifically, as the temperature increases or the heating time extends, the content of MRPs will present exponential growth. For example:

[0004] Wang et al. (Effect of heat treatment process on nutrient digestion and absorption in infant formula powder [J]. Clinical Journal of Pediatrics, 2016, 34(03): 237-240.) showed that the Maillard reaction occurring during heat treatment had a significant impact on the nutritional value of protein (especially whey protein). The specific mechanism is as follows: 1) reduced protein digestibility: the Maillard reaction modifies the amino sites of proteins through glycation, and the steric hindrance formed hinders the approach of digestive enzymes to the cleavage sites of proteins, thereby reducing the sensitivity of proteins to enzymolysis, which indicates that the structural changes of proteins caused by heat treatment may confer certain anti-digestive properties; 2) decreased bioavailability of lysine: lysine residues in whey protein have high reactivity and are easily combined with the carbonyl group of reducing sugars such as lactose and galactose. Neither the initial products of the Maillard reaction (such as lactulose lysine and fructose lysine) nor the intermediate products (such as furan amino acid) can be dissociated by digestive enzymes, resulting in a significant decrease in their bioavailability. The results of this study suggest that the heat treatment process during the production of infant formula powder may affect the digestion and absorption of protein through the Maillard reaction, thereby reducing its nutritional value.

[0005] Li (Analysis of whey protein components and evaluation of nutritional value of bovine milk whey protein treated by different heat treatments [D]. Northeast Agricultural University, 2012.) showed that different heat treatment processes had a significant impact on the nutritional value of bovine milk whey protein. The data showed that the loss rate of lysine in commercially available desalted whey powder treated by spray drying (inlet temperature 180℃, outlet temperature 90℃) was as high as 25.51%, which was 25 times that of heat-treated 85℃ / 15s pasteurized whey and 15.28% higher than that of 95℃ / 20min heat-treated whey. This result confirmed that the loss of lysine increased significantly with the increase of heat treatment intensity. It is worth noting that the ineffective lysine formed during heat treatment (such as bound lysine in Maillard reaction products) cannot be dissociated by digestive enzymes, and its increase will directly reduce the nutritional value of protein in desalted whey powder. Since lysine is an essential amino acid for the growth and development of infants, its decrease will lead to an imbalance in the amino acid pattern of protein, thereby reducing the bioavailability of protein. This phenomenon is particularly critical for infants who rely on formula milk powder as their only or main source of protein, and may have an adverse impact on their protein nutritional status. The results of this study suggest that during the production of infant formula milk powder, the intensity of heat treatment should be strictly controlled to maximize the retention of the nutritional value of whey protein and ensure that infants receive high-quality protein nutrition.

[0006] Maillard reaction induced by excessive heat treatment not only reduces the bioavailability of nutrients, but also produces a variety of potentially harmful by-products. This problem is particularly prominent in infant formula powder, which usually has a significantly higher content of Maillard reaction products than other dairy products. Since formula powder is the only or main source of nutrition for non-breastfed infants, this persistent high level of Maillard reaction product exposure poses a food safety hazard that cannot be ignored. Although there is currently insufficient long-term research on the impact of Maillard reaction products on infant health, several findings are highly concerning: 1) Li Y et al. (Whey protein processing influences formula-induced gut maturation in preterm pigs [J]. J Nutr, 2013, 143(12): 1934-1942.) found that infant formula powder prepared with heat-treated whey protein affects the development of the intestinal tract in preterm piglets, specifically abnormal intestinal tissue structure, impaired function, and decreased barrier integrity, ultimately delaying the normal maturation process of the intestinal tract. 2) Mericq V et al. (Maternally transmitted and food-derived glycotoxins: a factor preconditioning the young to diabetes [J]. Diabetes Care, 2010, 33(10): 2232-2237.) found that the plasma level of furfurylamine in infants fed with formula powder was significantly increased, and this increased state may persist into adulthood. This persistent exposure to Maillard reaction products may increase the risk of metabolic diseases such as diabetes by increasing oxidative stress and inflammation. These findings suggest that high levels of Maillard reaction product exposure in infant formula powder may have multiple adverse effects on infant growth and development, and it is necessary to draw the attention of the industry and researchers. To protect the health of infants, it is necessary to further study the safety threshold of Maillard reaction products and optimize the production process to reduce their generation.

[0007] Whey protein is more susceptible to Maillard reaction than casein protein due to its higher lysine content. It is worth noting that the desalted whey protein powder, which is widely used in infant formula, has already undergone multiple heat treatments including pasteurization, concentration, DSI sterilization and spray drying during the raw material production stage. The cumulative effect of heat treatment leads to a significantly higher content of Maillard reaction products in infant formula than in ordinary dairy products. The study by Birlouez-Aragon I et al. (Assessment of protein glycation markers in infant formulas [J]. Food Chem, 2004, 87(2): 253-259.) provides empirical data for this. The study compared 41 mainstream infant formulas, 7 similar heat-treated cow's milk and 7 ordinary milk powder sold on the French, Spanish and German markets. The results showed that: 1) the content of furfuryl amino acid in infant formula was 2-3 times that of cow's milk and ordinary milk powder; 2) the content of glycation end products (AGEs) was 2-5 times that of the control sample; 3) based on biochemical indicators, the loss of lysine in formula was about 6 times that of fresh cow's milk. These data fully illustrate that multiple heat treatments during the production of infant formula can significantly exacerbate the Maillard reaction, thereby affecting the nutritional quality of the product. This finding has important guiding significance for optimizing the production process of infant formula.

[0008] Milk is the main raw material for infant formula, which has significant differences in nutritional composition compared with breast milk. In order to simulate the nutritional composition of breast milk, additional ingredients such as lactose powder, whey protein and skim milk powder are added to adjust the protein and carbohydrate content during the production of infant formula. To meet the requirements of industrial production and storage, whey protein is usually added in the form of desalted whey protein powder or concentrated whey protein powder. However, this processing method may have a significant impact on the nutritional value of protein. Numerous studies have confirmed that the nutritional loss of whey protein during processing and storage cannot be ignored: 1) Li Xing's research (Research on the Digestion and Absorption Mechanism of Milk Protein during Heat Treatment and Storage[D]. Harbin Institute of Technology, 2021.) showed that with the increase of heat treatment intensity and the extension of storage time, the total amount of amino acids produced by milk protein hydrolysis increased, but the proportion of essential amino acids decreased significantly, which damaged the balance of amino acids, and this change may affect the utilization efficiency of protein by infants and young children. 2) Li Qian's research (Analysis of the composition of whey protein in milk treated by different heat treatments and evaluation of its nutritional value[D]. Northeast Agricultural University, 2012.) pointed out that desalted whey powder needs to undergo multiple heat treatments and secondary spray drying during the production of infant formula, which will lead to: the denaturation rate of protein increases significantly, the solubility of protein decreases, part of the functional properties is lost, and the in vivo digestibility decreases; these changes not only reduce the nutritional value of desalted whey powder, but also may affect the absorption and utilization of key nutrients by infants and young children, and have potential adverse effects on their healthy growth. This finding suggests that in the production of infant formula, the processing technology needs to be optimized to maximize the retention of the nutritional value of protein.

[0009] Currently, the main production processes of infant formula milk powder are wet process, dry process and dry-wet combined process. For example:

[0010] CN116250570B discloses a method for preparing infant formula milk powder, which adopts a dry-wet composite process, specifically: raw milk, lactose, full-fat milk powder, skim milk powder, whey protein powder, desalted whey powder, alpha-whey protein powder, sunflower oil and other raw materials are subjected to processes such as batching, filtering, homogenizing, cooling, concentration sterilization, spray drying, fluidized bed drying and cooling to obtain a semi-finished product, and then DHA, ARA, lactoferrin, nucleotides, probiotics and other raw materials are added to the semi-finished product for dry mixing to obtain a finished product. At the same time, the production methods reported in documents CN116158469B, CN103504025A, CN115769840A, CN117898337A and CN102283289A all use cow milk deep processing raw materials as the main ingredients, including full-fat milk powder, desalted whey powder, skim milk powder and the like. These raw materials have undergone multiple high-intensity heat treatments in the primary processing process, leading to the formation of Maillard reaction products. When these raw materials are used for infant formula milk powder production, they need to undergo heat treatment processes such as DSI sterilization, concentration, spray drying, etc., causing further accumulation of Maillard reaction products. This multi-stage, repetitive heat treatment process can significantly increase the content of Maillard reaction products in the final product, which may adversely affect the product quality and nutritional value.

[0011] CN101984836A discloses a method for producing infant formula milk powder using a dry process, which process is as follows: first, mix lactose with vegetable oil, homogenize and emulsify, evaporate and concentrate, and spray dry to produce vegetable fat powder, then mix the vegetable fat powder with full-fat milk powder, skim milk powder, whey protein powder, and ARA, DHA, lactoferrin, nucleotides, taurine, choline and other nutrients through dry mixing process. However, this method has the following potential problems: 1) accumulation of Maillard reaction products: the use of full-fat milk powder, skim milk powder, whey protein powder and other cow milk deep processing raw materials may undergo Maillard reaction during storage, influenced by factors such as moisture content, water activity (Aw), temperature, sugar and amino acid composition, among which temperature and water activity (Aw>0.3) are the key factors - an increase in temperature can significantly accelerate the Maillard reaction, and water activity can further promote the reaction. Therefore, as the storage time increases, the content of Maillard reaction products in the raw materials may continue to increase, affecting the quality of the final product; 2) mixing uniformity and nutrient distribution: the mixing uniformity of dry process is usually not as good as that of wet process, which may lead to uneven distribution of nutrients (such as ARA, DHA, lactoferrin, etc.) in the finished product, affecting the nutritional stability and batch consistency of the product. SUMMARY

[0012] PROBLEMS TO BE SOLVED BY THE INVENTION

[0013] As mentioned above, the quality of nutrients in formula milk powder, especially infant formula milk powder, is particularly important as the sole and main food for non-breastfed infants in the early stage of life. Repeated excessive heat treatment during the production of infant formula milk powder, although helpful for microbial safety and eating convenience, can reduce the digestion and utilization efficiency of nutrients such as protein, lactose, fat and vitamins. Studies have shown that Maillard reaction products (MRPs) are mainly derived from high-temperature treatment during the production of infant formula milk powder, and high-temperature treatment not only increases the denaturation degree of whey protein, but also reduces its digestion and absorption rate in vivo.

[0014] The traditional production process usually uses solid ingredients such as skim milk powder, desalted whey powder and concentrated whey protein powder for mixing, homogenization and other treatments to obtain the final formula milk powder, which has high efficiency, but the acquisition of these powder raw materials may also lead to an increase in Maillard reaction due to multiple heat treatments or long-term storage. In addition, for the process of generating formula milk powder from liquid milk of animal milk origin as raw material, although the introduction of multiple heating and spraying processes can be avoided, different heat treatments may occur during the separation of various liquid raw materials from animal milk.

[0015] Therefore, there are concerns about the increase of Maillard reaction products and the increase of whey protein denaturation rate (affecting digestion and absorption) in the processing of various formula milk powders mentioned above, which not only results in a loss of nutrients, but also a downward trend in product solubility and stability. Therefore, how to reduce the heat treatment intensity during the production of infant formula milk powder is the key to reducing Maillard reaction products and maintaining the natural structure of whey protein.

[0016] During the research, it was unexpectedly found that, on the basis of meeting various health requirements and basic nutrient formula, the Maillard reaction products and the denaturation rate of whey protein in infant formula milk powder can be effectively reduced by using full-liquid protein raw material feeding combined with mild heat treatment process, while the solubility and digestion and absorption performance of the product are improved. This technology provides an innovative solution for producing safer and more nutritious formula milk powder, especially for non-breastfed infants who are sensitive to protein.

[0017] Solution to the problem

[0018] In order to solve the above technical problems, the present application adopts a process route of full-liquid protein raw material feeding, especially using membrane technology to obtain skimmed liquid milk and desalted liquid whey as part of the raw material, and discarding the traditional high-temperature treatment of dry powder raw materials, thereby producing infant formula milk powder with high freshness, low Maillard reaction products and high digestion and absorption rate.

[0019] [1]. The present application provides a preparation method of formula milk powder, wherein the method comprises:

[0020] mixing, a step of mixing the raw milk raw material liquid, the skim milk raw material liquid, the desalted whey raw material liquid, and optionally other allowable addition of temperature-sensitive components;

[0021] spray drying, a step of spray drying the mixture obtained in the mixing step to obtain a powder;

[0022] wherein, in the mixing step:

[0023] the raw milk raw material liquid is a pasteurized milk liquid directly from an animal;

[0024] the skim milk raw material liquid is a milk liquid obtained by centrifugal separation of animal milk;

[0025] the desalted whey raw material liquid is a milk liquid obtained by whey separation and desalination of whey from animal milk, and the whey separation is a whey separation by membrane separation, and the desalination of whey is a removal of salt in whey by membrane separation;

[0026] the denaturation rate of whey protein in the formula milk powder is 11% or less.

[0027] [2]. The method according to [1], wherein the raw milk raw material liquid, the skim milk raw material liquid, and the desalted whey raw material liquid are all from cow milk, goat milk, or horse milk.

[0028] [3]. The method according to [1] or [2], wherein, in the preparation of the skim milk raw material liquid: after the centrifugal separation, the skim milk raw material liquid is obtained by one or both of pasteurization and membrane concentration.

[0029] [4]. The method according to any one of [1] to [3], wherein, in the preparation of the desalted whey raw material liquid: the whey separation is performed by microfiltration membrane treatment, and the desalination of whey is performed by electrodialysis treatment.

[0030] [5]. The method according to [4], wherein, between the microfiltration membrane treatment and the electrodialysis treatment, a nanofiltration membrane treatment process is further included to concentrate the whey liquid to be subjected to electrodialysis.

[0031] [6]. The method according to any one of [1] to [5], wherein, after the spray drying to obtain the powder, the powder is further mixed with optional other allowable addition of temperature-sensitive components.

[0032] [7]. The method according to any one of [1] to [6], wherein, in the mixing step, a homogenization treatment is included.

[0033] [8]. The method according to any one of [1] to [7], wherein, between the mixing step and the spray drying step, one or both of a composition adjustment step and a sterilization step are further included.

[0034] [9]. The method according to any one of [1] to [8], wherein,

[0035] the skim milk raw material liquid has a dry matter content of 9 to 25 mass% and a fat content of 0.1 mass% or less;

[0036] the desalted whey raw material liquid has a conductivity of 1.5 mS / cm or less;

[0037] the mixture to be spray dried has a dry matter content of 40 to 60 mass%.

[0038]

[0010] . The method according to any one of [1] to [9], wherein, the formula milk powder has a furfuryl amino acid content of 500 mg / 100 g of protein or less.

[0039] Effects of the Invention

[0040] Through implementation of the above technical solutions, the following technical effects are achieved:

[0041] 1) Avoiding multiple heat treatments: The process route of using full-liquid protein raw materials is adopted, and in particular, a membrane process is adopted to obtain skimmed liquid milk and desalted liquid whey as part of the raw materials, so that the use of skimmed milk powder, desalted whey powder, concentrated whey protein powder and other raw materials subjected to repeated high-temperature treatment is avoided, the occurrence of Maillard reaction is reduced, and the natural structure of protein is maximally preserved.

[0042] 2) Reducing denaturation of whey protein: Low-temperature evaporation concentration and optimized spray drying process (such as reducing the exhaust air temperature) are adopted to reduce protein thermal denaturation; the retention degree of the natural conformation of whey protein in the product is high, and the digestion and absorption rate is significantly better than that of the product of the traditional process.

[0043] 3) Reducing Maillard reaction products (MRPs): Compared with the traditional process, the content of harmful substances such as furfuryl amino acid in the formula milk powder of the present application is significantly reduced; it is closer to the protein digestion mode of breast milk, and reduces the potential health risks (such as metabolic burden and intestinal irritation).

[0044] 4) Improving the reconstitution performance: Due to the low degree of protein denaturation, the solubility and dispersibility of the product are better, the caking phenomenon is reduced, and the feeding experience is improved. BRIEF DESCRIPTION OF DRAWINGS

[0045] FIG. 1: Process flow diagram for preparing the formula milk powder of the embodiment of the present application;

[0046] FIG. 2: Solubility state evaluation standard;

[0047] Figure 3: Vitiligo evaluation criteria. DETAILED DESCRIPTION

[0048] Various illustrative embodiments, features and aspects of the present application are described in detail herein. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any implementation described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other implementations.

[0049] In addition, numerous specific details are set forth in the following description. Those of ordinary skill in the art will understand that the application can be practiced without the

[0050] Unless otherwise indicated, the units used in the present specification are international standard units, and the numerical values, numerical ranges appearing in the present application should be understood as including the systematic errors that are inevitable in industrial production.

[0051] In the present specification, the meaning of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0052] In the present specification, "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", and the like refer to the specific elements (e.g., features, structures, properties, and / or characteristics) described in relation to the embodiments, and can be present in other embodiments or can not be present in other embodiments. In addition, it should be understood that the elements can be combined in various embodiments in any suitable manner.

[0053] In the present specification, the numerical range expressed using "numerical value A to numerical value B" refers to a range including the end point values A, B.

[0054] In the present specification, the numerical range expressed using "above" or "below" refers to a range including the numerical value.

[0055] In the present specification, "optional" or "optionally" means that the use or non-use of certain substances, components, execution steps, application conditions, and the like.

[0056] In the present specification, the term "comprise", "have", "include" or "contain" can mean inclusive or open-ended and does not exclude additional, unrecited elements or method steps. At the same time, "comprise", "have", "include" or "contain" can also mean closed, excluding additional, unrecited elements or method steps.

[0057] In the present specification, the term "about" can mean that a value includes the standard deviation of error of the apparatus or method used to determine the value. The numerical ranges and parameters setting forth the scope of the application are approximations. The numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Therefore, any numerical value should be considered and treated as an approximation of the value sought to be conveyed. Other than in the operating / numerical examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, reaction, and / or use are to be understood as modified in all instances by the term "about." Accordingly, unless indicated to the contrary, with respect to quantity, the word "about" as used herein means ± 2° / o, ± 1 ° / o, or ± 0.5% of the indicated value.

[0058] In the present specification, "solid" and "dry matter" have the same meaning, and refer to the total solids in the food, including soluble solids and insoluble solids.

[0059] In the present specification, the "concentration factor" referred to means the weight ratio (or volume ratio) of the feed liquid before membrane filtration to the retentate of membrane filtration in the membrane filtration separation process, wherein the feed liquid before membrane filtration = the retentate of membrane filtration + the permeate of membrane filtration.

[0060] In the present specification, unless otherwise specified, the "conductivity" referred to herein is the conductivity at room temperature.

[0061] In the present specification, unless otherwise specified, "room temperature" or "ambient temperature" as used herein generally refers to a temperature of 23 ± 2 °C.

[0062] The present application provides a method for preparing a formula milk powder, wherein the method comprises:

[0063] The mixing step is a step of mixing the base milk raw material liquid, the skim milk raw material liquid, the desalted whey raw material liquid, and optionally other non-temperature sensitive components allowed to be added.

[0064] The spray drying step is a step of spray drying the mixture obtained in the mixing step to obtain a powder.

[0065] The mixing step

[0066] The mixing step in the present application is a step of mixing the base milk raw material liquid, the skim milk raw material liquid, the desalted whey raw material liquid, and optionally other non-temperature sensitive components allowed to be added.

[0067] (Base milk raw material liquid)

[0068] In the present application, the base milk raw material liquid is a pasteurized milk liquid directly from an animal.

[0069] In some embodiments, the milk raw material of the base milk raw solution is from cow milk, goat milk, horse milk, or colostrum, etc., preferably cow milk or goat milk, and more preferably cow milk.

[0070] Specifically, the preparation process of the base milk raw solution is as follows:

[0071] (1) Milk raw material acceptance: select standard raw cow milk as raw material; in some embodiments, the total number of colonies of the milk raw material is controlled within the range of relevant safety standards, for example, the total number of colonies of the milk raw material is controlled to be less than or equal to 1 × 10 5 cfu / mL.

[0072] (2) Preheating treatment: preheat the raw cow milk to 40-60℃ to optimize the subsequent milk purification effect.

[0073] (3) Milk purification and sterilization: sterilize and remove impurities from the preheated raw cow milk. Typically, a milk purifier can be used for milk purification and sterilization.

[0074] (4) Pasteurization: maintain at 80-90℃ for 10-20s, quickly cool to 6-10℃, ensure effective killing of pathogenic bacteria while maximizing the retention of nutritional ingredients, and ensure product freshness.

[0075] In some embodiments, the dry matter content of the base milk raw solution is 10-15% by mass, for example, 10%, 11%, 12%, 13%, 14%, 15%, etc.

[0076] (Defatted milk raw solution)

[0077] In the present application, the defatted milk raw solution is a milk solution obtained by centrifugal defatting of animal milk.

[0078] In some embodiments, the animal milk is from cow milk, goat milk, horse milk, or colostrum, etc., preferably cow milk or goat milk, and more preferably cow milk.

[0079] In some embodiments, in the preparation of the defatted milk raw solution, after centrifugal defatting, the defatted milk raw solution is obtained by one or both of pasteurization and membrane concentration.

[0080] Specifically, the preparation process of the defatted milk raw solution is as follows:

[0081] (1) Milk raw material acceptance: select standard raw cow milk as raw material; in some embodiments, the total number of colonies of the milk raw material is controlled within the range of relevant safety standards, for example, the total number of colonies of the milk raw material is controlled to be less than or equal to 1 × 10 5below 1000 cfu / mL.

[0082] (2) Preheating treatment: the raw milk is preheated to 40-60°C to optimize the subsequent milk purification effect.

[0083] (3) Centrifugal skimming: the preheated raw milk is skimmed at a speed of 4500-5500 r / min. Typically, a separator can be used for centrifugal skimming.

[0084] (4) Pasteurization: maintained at 80-90°C for 10-20 s, rapidly cooled to 6-10°C, to ensure effective killing of pathogenic bacteria while maximizing the retention of nutrients, ensuring product freshness.

[0085] (5) Membrane concentration: the skimmed milk after pasteurization is concentrated under an operating pressure of 20-30 bar. Typically, reverse osmosis (RO) membrane can be used for concentration treatment.

[0086] In some specific embodiments, the dry matter content of the skimmed milk raw material liquid is 9-25 mass%, preferably 15-20 mass%, for example, it can be 10 mass%, 12 mass%, 15 mass%, 18 mass%, 20 mass%, 22 mass%, 25 mass%, etc.; the fat content is below 0.1 mass%, preferably below 0.09 mass%, more preferably below 0.07 mass%, further preferably below 0.06 mass%.

[0087] (desalted whey raw material liquid)

[0088] In the present application, the desalted whey raw material liquid is a milk obtained by whey separation and whey desalination of animal milk, and the whey separation is whey separation by membrane separation, and the whey desalination is removal of salt in whey by membrane separation.

[0089] In some specific embodiments, the animal milk is from cow milk, goat milk, horse milk or their colostrum, etc., preferably it can be cow milk or goat milk, more preferably it can be cow milk.

[0090] In some specific embodiments, in the preparation of the desalted whey raw material liquid: the whey separation is carried out by microfiltration membrane treatment, and the whey desalination is carried out by electrodialysis treatment.

[0091] In some specific embodiments, between the microfiltration membrane treatment and the electrodialysis treatment, a nanofiltration membrane treatment process is further included to concentrate the whey liquid to be electrodialyzed.

[0092] Specifically, the preparation process of the desalted whey raw material liquid is as follows:

[0093] (1) Milk raw material acceptance: raw cow milk meeting the standard is selected as raw material; in some specific embodiments, the total number of colonies of the milk raw material is controlled within the range meeting the relevant safety standard, for example, the total number of colonies of the milk raw material is controlled to be below 1 x 10 5 cfu / mL.

[0094] (2) Preheating treatment: the raw cow milk is preheated to 40-60°C to optimize the subsequent milk purification effect.

[0095] (3) Centrifugal defatting: the raw cow milk after preheating treatment is subjected to defatting separation at a rotation speed of 4500-5500 r / min. Typically, a separator can be used for centrifugal defatting treatment. Preferably, the defatted milk obtained after centrifugal defatting treatment has a fat content of 0.1% by mass or less, preferably 0.09% by mass or less, more preferably 0.07% by mass or less, and further preferably 0.06% by mass or less.

[0096] (4) Pasteurization: the defatted milk after pasteurization is maintained at 80-90°C for 10-20 s, rapidly cooled to 6-10°C, to ensure effective killing of pathogenic bacteria while maximizing the retention of nutritional ingredients, thereby ensuring product freshness.

[0097] (5) Whey separation: the defatted milk after pasteurization is subjected to microfiltration separation to obtain whey liquid.

[0098] In some embodiments, the microfiltration separation includes subjecting the defatted milk after pasteurization to microfiltration membrane treatment to achieve separation of casein and whey.

[0099] In some specific embodiments, from the perspective of efficiency and separation effect, the conditions of the microfiltration separation include: the microfiltration membrane pore size is 0.05-0.2 μm, preferably 0.1-0.2 μm; the operating temperature is 5-20°C, preferably 10-20°C; and the operating pressure is 0.1-2 bar, preferably 0.5-1.5 bar. The material and form of the microfiltration membrane are not particularly limited in principle, and in some preferred embodiments, the microfiltration membrane can be polyether sulfone material; the microfiltration membrane can be further preferably a spiral membrane.

[0100] In addition, in the above-mentioned separation of casein treatment, since microfiltration separation is used, it also plays a sterilization role, and therefore, for the treatment of the present application, subsequent heat sterilization treatment such as pasteurization is not necessarily required to meet the safety requirements.

[0101] (6) Nanofiltration concentration: nanofiltration membrane is used to concentrate the whey liquid to obtain concentrated whey liquid. In the nanofiltration concentration of the present application, in addition to further concentrating the defatted and casein-free whey, it can also play a role in removing part of the inorganic salts.

[0102] In some specific embodiments, the conditions for the nanofiltration concentration include: the molecular weight cut-off of the nanofiltration membrane is 100-500 Da, preferably 150-300 Da; the concentration factor is 4-10 times, preferably 4-8 times; the operating temperature is 4-20°C, preferably 8-20°C. In principle, there is no particular limitation on the material of the nanofiltration membrane, and in some preferred embodiments, the nanofiltration membrane can be of polyethersulfone material.

[0103] In some specific embodiments, in the concentrated whey liquid, the solid content is 15-25% by mass, preferably 18-25% by mass; and the protein content is 10-20% by mass, preferably 10-15% by mass, based on the dry weight.

[0104] In some specific embodiments, before the nanofiltration concentration treatment, the step of subjecting the whey liquid to ultrafiltration is further included as needed. According to the ingredient ratio of the raw material, the step of removing part of the lactose and minerals in the whey liquid by ultrafiltration can be added to better ensure that the protein content of the final product meets the requirement of ≥10%.

[0105] In some specific embodiments, the conditions for the ultrafiltration include: the molecular weight cut-off of the ultrafiltration membrane is 5000-10000 Da; the operating temperature is 4-20°C, preferably 10-20°C. In principle, there is no particular limitation on the material of the ultrafiltration membrane, and in some preferred embodiments, the ultrafiltration membrane can be of polyethersulfone material.

[0106] (6) Whey desalination: subjecting the concentrated whey liquid to electrodialysis treatment until the conductivity is 1.5 mS / cm or less, preferably 0.5-1.5 mS / cm, to obtain a desalted whey liquid.

[0107] In some specific embodiments, the conditions for the electrodialysis include: the operating temperature is 8-20°C, preferably 10-20°C; the initial voltage is 10-30 V, preferably 15-25 V; the operating pH is controlled at 6-7, preferably 6.5-6.8, and the pH is appropriately adjusted to be acidic, so as to increase the solubility of calcium while ensuring that the protein does not precipitate due to excessively low pH, improve the efficiency of the electrodialysis equipment operation, prolong the operation time, and thus reduce the difficulty of cleaning the equipment.

[0108] In some specific embodiments, the dry matter content of the desalted whey feed solution is 15-25% by mass, preferably 18-25% by mass, for example, it can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25% or the like by mass; and the protein content is 10-20% by mass, preferably 10-15% by mass, for example, it can be 10%, 12%, 15%, 18%, 20% or the like by mass based on the dry weight.

[0109] In some specific embodiments, the non-temperature-sensitive components include one or more of lactose, edible fat, oligosaccharide, vitamin supplement, mineral supplement, nutrient supplement; the edible fat includes one or more of vegetable oil.

[0110] The present application does not particularly limit the specific sources of the above-mentioned non-temperature-sensitive components, for example, each raw material product can be purchased through commercial channels, or can be prepared by, for example, biological fermentation, physical purification and the like.

[0111] In some specific embodiments, the vegetable oil is selected from one or more of soybean oil, sunflower seed oil, coconut oil, flaxseed oil, corn oil, rapeseed oil and walnut oil, and can also be a blend oil formed by multiple oils, for example, a blend oil formed by soybean oil, sunflower seed oil, coconut oil and flaxseed oil.

[0112] In some specific embodiments, the oligosaccharide includes one or more of galactooligosaccharide, fructooligosaccharide, isomaltooligosaccharide and xylooligosaccharide, preferably galactooligosaccharide and fructooligosaccharide.

[0113] In some specific embodiments, the vitamin supplement is selected from one or more of vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin and taurine, and can also be a compound vitamin formed by multiple vitamins, for example, a compound vitamin formed by vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin and taurine.

[0114] In some specific embodiments, the mineral supplement is selected from one or more of calcium citrate, calcium hydrogen phosphate, magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate and sodium selenite, and can also be a compound mineral formed by multiple minerals, for example, a compound mineral formed by calcium citrate, calcium hydrogen phosphate, magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate and sodium selenite.

[0115] In some embodiments, the nutrient supplement is selected from one or more of choline chloride, lutein, inositol, and L-carnitine, and can also be a combination of multiple nutrients, such as a combination of choline chloride, lutein, inositol, and L-carnitine.

[0116] In some embodiments, the mixing step includes a homogenization process.

[0117] In some embodiments, the mixing conditions include a temperature of 40-50°C, a pressure of -(0.4-0.9) bar, and a time of 40-50 min.

[0118] In some embodiments, the homogenization conditions include a temperature of 50-60°C and a pressure of 230-250 bar.

[0119] The step of spray drying

[0120] In the step of spray drying of the present application, the mixture obtained in the step of mixing is spray dried to obtain a powder.

[0121] In some embodiments, between the step of mixing and the step of spray drying, one or both of a step of ingredient adjustment and a step of sterilization are further included. The step of ingredient adjustment and the step of sterilization can also be completed in one step (e.g., a multiple-effect evaporation concentration system), and further, the sterilization method can be DSI sterilization, and the sterilization conditions include a temperature of 85-97°C and a time of 5-15 s.

[0122] In some embodiments, the dry matter content of the mixture to be spray dried is 40-60% by mass, such as 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%, etc.

[0123] In some embodiments, the spray drying conditions include an inlet air temperature of 120-190°C and an exhaust air temperature of 65-95°C.

[0124] In some embodiments, after the powder is obtained by spray drying, the powder is mixed with optional other temperature-sensitive components that are allowed to be added.

[0125] In some embodiments, the temperature-sensitive components include one or more of a polyunsaturated fatty acid supplement, lactoferrin, probiotics, nucleotides, etc.

[0126] In some specific embodiments, the polyunsaturated fatty acid supplement includes arachidonic acid oil powder and / or docosahexaenoic acid oil powder.

[0127] In some specific embodiments, the arachidonic acid oil powder refers to a powder product processed after arachidonic acid oil (which can be derived from the Mortierella alpina species and prepared by biological fermentation) is used as a raw material, other food raw materials and food additives, such as whey protein powder, whey powder, modified starch, malt dextrin, lactose, white sugar, acacia gum, sodium octenyl succinate starch, sodium caseinate, vitamin E, ascorbic acid palmitate, and the like, are added.

[0128] In some specific embodiments, the docosahexaenoic acid oil powder refers to a powder product processed after docosahexaenoic acid oil (which can be derived from the Schizochytrium sp., Emiliana huxleyi, and other species and prepared by biological fermentation) is used as a raw material, other food raw materials and food additives, such as whey protein powder, whey powder, modified starch, malt dextrin, lactose, white sugar, acacia gum, gelatin, sodium octenyl succinate starch, sodium caseinate, vitamin E, ascorbic acid palmitate, and the like, are added.

[0129] Other steps

[0130] The preparation method of the present application is not limited to the above steps, and other steps can also be included as needed within the scope that does not affect the effect of the present application. For example, in order to improve the reliability of the product, the preparation method of the present application can further include a sterile filling step and a finished product step. The sterile filling step is a step of sterile filling the powder prepared by the above steps into a packaging container. As a packaging container, there is no particular limitation as long as it is a packaging container that can be used in the food industry. The finished product step refers to a step of performing online detection, coding, boxing, coding, and stacking as needed after filling, and then storing in a warehouse.

[0131] In some specific embodiments, the denaturation rate of whey protein in the formula milk powder is 11% or less, preferably 10% or less, more preferably 9.5% or less, and further preferably 9% or less.

[0132] In some specific embodiments, the formula milk powder has a furfuryl amino acid content of 500 mg / 100 g of protein or less, preferably 480 mg / 100 g of protein or less, more preferably 470 mg / 100 g of protein or less, and further preferably 460 mg / 100 g of protein or less.

[0133] Examples

[0134] The embodiments of the present application will be described in detail below with reference to Examples, but those skilled in the art will appreciate that the following Examples are intended to be illustrative only and should not be viewed as limiting the scope of the present application. Where specific conditions are not mentioned in the Examples, they are carried out under conventional conditions or conditions recommended by the manufacturer. Where the manufacturer of the reagent or instrument is not mentioned, it is a conventional product that can be obtained commercially.

[0135] Example 1:

[0136] 1. Preparation of skim milk

[0137] The raw milk that passed the acceptance test was preheated to 50°C, and then introduced into a separator to perform skimming at a rotation speed of 5000 r / min, with the requirement that the fat content of the skim milk be <0.1%. The skim milk that passed the test was subjected to pasteurization at a temperature of 85°C for 15 s, with the outlet temperature controlled at 6°C.

[0138] The skim milk after pasteurization was concentrated by RO membrane, with the operating pressure controlled at 23 bar, the dry matter content at the outlet controlled at 10%, and the temperature at 6°C. The concentrated skim milk was temporarily stored in a milk tank.

[0139] 2. Preparation of membrane desalted whey

[0140] (1) Skimming of raw milk

[0141] The raw milk that passed the acceptance test was preheated to 50°C, and then introduced into a separator to perform skimming at a rotation speed of 5000 r / min, with the requirement that the fat content of the skim milk be <0.1%. The skim milk that passed the test was subjected to pasteurization at a temperature of 85°C for 15 s, with the outlet temperature controlled at 6°C.

[0142] (2) Microfiltration separation

[0143] The above skim milk was introduced into a microfiltration membrane to remove casein, to obtain whey. The microfiltration membrane was made of polyether sulfone, with a pore size of 0.1 μm, an operating temperature of 10°C, and an operating pressure of 1.0 bar.

[0144] (3) Ultrafiltration standardization

[0145] The whey obtained by microfiltration was subjected to ultrafiltration standardization. The ultrafiltration membrane was made of polyether sulfone, with a molecular weight cut-off of 5000-10000 Da, an operating temperature of 10°C, and the protein content in the outlet liquid controlled at 12% of the total solids.

[0146] (4) Nanofiltration concentration

[0147] The ultrafiltration standardized whey liquid is concentrated by a nanofiltration membrane with a molecular weight cut-off of 100-500 Da, a concentration ratio of about 4 times, and an operating temperature of 10°C. The solid content of the nanofiltration outlet is 15%.

[0148] (5) Desalination by electrodialysis

[0149] The concentrated whey liquid is desalted by electrodialysis, and the conductivity is reduced to 1.0 mS / cm to obtain desalted whey. The electrodialysis operating temperature is 10°C, the initial voltage is 20V, and the operating pH is controlled at 6.8.

[0150] 3. Preparation of pasteurized milk

[0151] The raw cow milk that passes the acceptance test is first preheated to 50°C, and then sterilized and clarified by a milk clarifier before pasteurization at a temperature of 85°C for 15s, and the outlet temperature is controlled at 6°C.

[0152] 4. Mixing and homogenization

[0153] According to the requirements, 2200 kg of pasteurized milk (dry matter 270 kg), 1700 kg of skim milk (dry matter content 10%), and 833 kg of desalted whey liquid (dry matter content 15%) are fed into a vacuum mixer, and the mixture is circulated at -0.9 bar and 45°C. During the process, 130 kg of edible vegetable blend oil (soybean oil, sunflower oil, coconut oil, flaxseed oil), 200 kg of lactose, 75 kg of galacto-oligosaccharides, 6 kg of calcium citrate, 5 kg of fructo-oligosaccharides, 1 kg of calcium hydrogen phosphate, 3 kg of vitamin premix (vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin, taurine), 2 kg of choline chloride, 2 kg of mineral premix (magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate, sodium selenite), and 1 kg of nutrient premix (lutein, inositol, L-carnitine) are added. The mixing time lasts for 45 min, and then the mixed liquid is preheated to 50°C by a plate heat exchanger, homogenized at a pressure of 240 bar, cooled to 8°C by a plate heat exchanger after homogenization, and stored. The theoretical dry matter content of the above mixed liquid is 19%, and the actual dry matter content is 14.8% due to the presence of material and water during the production process. About 1.5 tons of process water enters the mixed liquid during the production process.

[0154] 5. Evaporation and concentration

[0155] The mixed liquid enters the evaporator for concentration, and the operating conditions are as follows: DSI sterilization temperature 90°C, sterilization time 10s, one-effect vacuum degree -900mbar, one-effect temperature 70°C, two-effect temperature 65°C, three-effect temperature 60°C, and outlet liquid concentration controlled at 50%, to obtain the mixture.

[0156] 6. Spray drying

[0157] The mixture is preheated to 75°C, pumped into the drying tower by a high-pressure pump for spray drying, the inlet air temperature is 180°C, and the exhaust air temperature is 75°C, and after secondary drying and cooling by a dynamic fluidized bed, the semi-finished powder is obtained and temporarily stored in a powder bin.

[0158] 7. Dry mixing and packaging

[0159] 990kg of semi-finished powder, 5kg of docosahexaenoic acid oil powder (7%), and 5kg of arachidonic acid oil powder (10%) are dry mixed, and then filled into cans.

[0160] Example 2:

[0161] 1. Preparation of skimmed milk

[0162] The raw cow milk that passes acceptance is preheated to 50°C, and then enters the separator for defatting at a speed of 5000r / min, and the fat content of the skimmed milk is required to be less than 0.1%, and the qualified skimmed milk is subjected to pasteurization at a temperature of 85°C for 15s, and the outlet temperature is controlled at 8°C.

[0163] The skimmed milk after pasteurization is concentrated by an RO membrane, the operating pressure is 23bar, the dry matter at the outlet is controlled at 18%, and the temperature is 8°C, and the concentrated skimmed milk is temporarily stored in a milk tank.

[0164] 2. Preparation of desalted whey liquid by membrane method

[0165] (1) Defatting of raw cow milk

[0166] The raw cow milk that passes acceptance is preheated to 50°C, and then enters the separator for defatting at a speed of 5000r / min, and the fat content of the skimmed milk is required to be less than 0.1%, and the qualified skimmed milk is subjected to pasteurization at a temperature of 85°C for 15s, and the outlet temperature is controlled at 8°C.

[0167] (2) Microfiltration separation

[0168] The above skimmed milk enters a microfiltration membrane to remove casein to obtain whey liquid; the microfiltration membrane is made of polyether sulfone material, the pore size of the microfiltration membrane is 0.1μm, the operating temperature is 15°C, and the operating pressure is 1.0bar.

[0169] (3) Ultrafiltration standardization

[0170] The microfiltration whey liquid is then standardized by ultrafiltration, the ultrafiltration membrane is made of polyether sulfone material, the molecular weight cut-off of the ultrafiltration membrane is 5000-10000 Da, the operating temperature is 15°C, and the protein content in the outlet liquid is controlled to be 12% of the total solids.

[0171] (4) Nanofiltration concentration

[0172] The ultrafiltration standardized whey liquid is then concentrated by nanofiltration membrane, the molecular weight cut-off of the nanofiltration membrane is 100-500 Da, the concentration ratio is about 5 times, the operating temperature is 15°C, and the solid content of the nanofiltration outlet is required to be 20%.

[0173] (5) Desalination by electrodialysis

[0174] The concentrated whey liquid is desalted by electrodialysis, the conductivity is reduced to 1.0 mS / cm, and desalted whey is obtained; the electrodialysis operating temperature is 15°C, the initial voltage is 20V, and the operating pH is controlled at about 6.5.

[0175] 3. Preparation of pasteurized milk

[0176] The raw cow milk that has passed the acceptance test is preheated to 50°C, then sterilized and clarified by a milk clarifier, and then pasteurized at a temperature of 85°C for 15s, and the outlet temperature is controlled at 8°C.

[0177] 4. Mixing and homogenization

[0178] According to the requirements, 2200 kg of pasteurized milk (dry matter 270 kg), 945 kg of skim milk (dry matter content 18%), and 625 kg of desalted whey liquid (dry matter content 20%) are fed into a vacuum mixer, and the mixture is circulated at -0.9 bar and 45°C; During the process, 130 kg of edible vegetable blend oil (soybean oil, sunflower oil, coconut oil, flaxseed oil), 200 kg of lactose, 75 kg of galacto-oligosaccharides, 6 kg of calcium citrate, 5 kg of fructo-oligosaccharides, 1 kg of calcium hydrogen phosphate, 3 kg of vitamin premix (vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin, taurine), 2 kg of choline chloride, 2 kg of mineral premix (magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate, sodium selenite), and 1 kg of nutrient premix (lutein, inositol, L-carnitine) are added; The mixing time lasts for 45 min, then the mixed liquid is preheated to 50°C by a plate heat exchanger, homogenized at a pressure of 240 bar, cooled to 8°C by a plate heat exchanger after homogenization, and stored; The theoretical dry matter content of the above mixed liquid is 23.6%, and the actual dry matter content is 17.5% due to the presence of material and water during the production process, and about 1.5 tons of process water enters the mixed liquid during the production process.

[0179] 5. Evaporation concentration

[0180] The mixed liquid enters the evaporator for concentration, and the operating conditions are as follows: DSI sterilization temperature 90°C, sterilization time 15s, one-effect vacuum degree -950mbar, one-effect temperature 70°C, two-effect temperature 65°C, three-effect temperature 60°C, and outlet liquid concentration controlled at 50%, to obtain the mixture.

[0181] 6. Spray drying

[0182] The mixture is preheated to 75°C, pumped into the drying tower by a high-pressure pump for spray drying, the inlet air temperature is 180°C, and the exhaust air temperature is 75°C, and after secondary drying and cooling by a dynamic fluidized bed, the semi-finished powder is obtained and temporarily stored in a powder bin.

[0183] 7. Dry mixing and packaging

[0184] 990kg of semi-finished powder, 5kg of docosahexaenoic acid oil powder (7%), and 5kg of arachidonic acid oil powder (10%) are dry mixed, and then filled into cans.

[0185] Example 3:

[0186] 1. Preparation of skimmed milk

[0187] The raw cow milk that has passed acceptance is preheated to 50°C, and then enters the separator for defatting at a speed of 5000r / min, and the fat content of the skimmed milk is required to be less than 0.1%, and the qualified skimmed milk is subjected to pasteurization at a temperature of 85°C for 15s, and the outlet temperature is controlled at 8°C.

[0188] The skimmed milk after pasteurization is concentrated by RO membrane, the operating pressure is 23bar, the dry matter at the outlet is controlled at 25%, and the temperature is 8°C, and the concentrated skimmed milk is temporarily stored in a milk tank.

[0189] 2. Preparation of desalted whey liquid by membrane method

[0190] (1) Defatting of raw cow milk

[0191] The raw cow milk that has passed acceptance is preheated to 50°C, and then enters the separator for defatting at a speed of 5000r / min, and the fat content of the skimmed milk is required to be less than 0.1%, and the qualified skimmed milk is subjected to pasteurization at a temperature of 85°C for 15s, and the outlet temperature is controlled at 8°C.

[0192] (2) Microfiltration separation

[0193] The above skimmed milk enters the microfiltration membrane to remove casein to obtain whey liquid; the microfiltration membrane is made of polyether sulfone material, the pore size of the microfiltration membrane is 0.1μm, the operating temperature is 15°C, and the operating pressure is 1.0bar.

[0194] (3) Ultrafiltration standardization

[0195] The microfiltration whey liquid is subjected to ultrafiltration standardization. The ultrafiltration membrane is made of polyether sulfone, the molecular weight cut-off of the ultrafiltration membrane is 5000-10000 Da, the operating temperature is 15°C, and the protein content in the outlet liquid is controlled to be 12% of the total solids.

[0196] (4) Nanofiltration concentration

[0197] The ultrafiltration-standardized whey liquid is subjected to concentration through a nanofiltration membrane. The molecular weight cut-off of the nanofiltration membrane is 100-500 Da, the concentration multiple is about 6, the operating temperature is 15°C, and the solid content at the nanofiltration outlet is required to be 25%.

[0198] (5) Electrodialysis desalination

[0199] The concentrated whey liquid is subjected to electrodialysis desalination, and the conductivity is reduced to 1.0 mS / cm to obtain desalted whey. The electrodialysis operating temperature is 15°C, the initial voltage is 20V, and the operating pH is controlled at 6.5.

[0200] 3. Pasteurized milk preparation

[0201] The raw cow milk that passes the acceptance check is preheated to 50°C, then sterilized and clarified by a milk clarifier, and then subjected to pasteurization at a temperature of 85°C for 15s, and the outlet temperature is controlled at 8°C.

[0202] 4. Mixing and homogenization

[0203] According to the requirements, 2200 kg of pasteurized milk (dry matter 270 kg), 680 kg of skim milk (dry matter content 25%), 500 kg of desalted whey liquid (dry matter content 25%) are fed into the vacuum mixer, and the circulating mixing is carried out at -0.9 bar, 45°C; during the process, 130 kg of edible vegetable blend oil (soybean oil, sunflower oil, coconut oil, flaxseed oil), 200 kg of lactose, 75 kg of galacto-oligosaccharide, 6 kg of calcium citrate, 5 kg of fructo-oligosaccharide, 1 kg of calcium hydrogen phosphate, 3 kg of vitamin premix (vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin, taurine), 2 kg of choline chloride, 2 kg of mineral premix (magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate, sodium selenite), 1 kg of nutrient premix (lutein, inositol, L-carnitine); the mixing time lasts for 45 min, then the mixed liquid is preheated to 55°C through a plate heat exchanger, homogenized at 240 bar pressure, and then cooled to 8°C through a plate heat exchanger after homogenization, and stored; the above mixed liquid has a theoretical dry matter content of 26%, and due to the presence of material top water and water top material during the production process, the actual dry matter content is 18.7%, and about 1.5 tons of process water enters the mixed liquid during the production process.

[0204] 5. Evaporation concentration

[0205] The mixed liquid enters the evaporator for concentration, and the operating conditions are: DSI sterilization temperature 90°C, sterilization time 15s, primary vacuum degree -950mbar, primary temperature of one effect: 70°C, primary temperature of two effects: 65°C, primary temperature of three effects: 60°C, and the outlet liquid concentration is controlled at 50%, to obtain the mixed material.

[0206] 6. Spray drying

[0207] The mixed material is preheated to 75°C, pumped into the drying tower for spray drying through a high-pressure pump, the inlet air temperature is 180°C, and the exhaust air temperature is 75°C, after secondary drying and cooling in a dynamic fluidized bed, the semi-finished powder is obtained, and stored in a powder bin.

[0208] 7. Dry mixing and packaging

[0209] Take 990 kg of semi-finished powder, 5 kg of docosahexaenoic acid oil powder (7%), and 5 kg of arachidonic acid oil powder (10%) for dry mixing, and then fill into cans after completion.

[0210] Comparative Example 1:

[0211] 1. Preparation of skim milk

[0212] The raw milk passed the acceptance, first preheated to 50℃, then into the separator, at a speed of 5000r / min defatting, defatted milk fat content <0.1%, qualified defatted milk pasteurization, temperature 85℃, time 15s, outlet temperature control at 8℃;

[0213] The defatted milk after pasteurization through the RO membrane concentration, operating pressure 23bar, control outlet dry matter 18%, temperature 8℃, concentrated defatted milk into the tank temporary storage.

[0214] 2. Preparation of enzyme desalted whey liquid

[0215] (1) raw milk defatting

[0216] The raw milk passed the acceptance, first preheated to 50℃, then into the separator, at a speed of 5000r / min defatting, defatted milk fat content <0.1%, qualified defatted milk pasteurization, temperature 85℃, time 15s, outlet temperature control at 8℃.

[0217] (2) curd filtration

[0218] According to the amount of defatted milk, according to the quality ratio 0.0045% to add quantitative Caglificio Clerici rennet (gastric enzyme, bovine pepsin, activity 1:100000), mix evenly, curd 40min, after curd, collect whey liquid through 50μm membrane filtration and then through pasteurization enzyme treatment, temperature 85℃, time 15s, get whey liquid.

[0219] (3) ultrafiltration standardization

[0220] The obtained whey liquid, again ultrafiltration standardization, ultrafiltration membrane is polyether sulfone material, the molecular weight cut-off of ultrafiltration membrane is 5000~10000Da, the operating temperature is 15℃, control the protein content in the outlet liquid to reach 12% of the total solid.

[0221] (4) nanofiltration concentration

[0222] The whey liquid after ultrafiltration standardization is concentrated through nanofiltration membrane, the molecular weight cut-off of nanofiltration membrane is 100~500Da, the concentration multiple is about 5 times, the operating temperature is 15℃; the solid content of nanofiltration outlet is required to be 20%.

[0223] (5) electrodialysis desalination

[0224] The concentrated whey liquid is desalted by electrodialysis, the conductivity is reduced to 1.0mS / cm, and the desalted whey is obtained; the electrodialysis operating temperature is 15℃, the initial voltage is 20V, and the operating pH is controlled at 6.5.

[0225] 3. Preparation of pasteurized milk

[0226] The raw milk that passed the acceptance test was preheated to 50°C, then sterilized by a milk filter at 85°C for 15s, and the outlet temperature was controlled at 8°C.

[0227] 4. Mixing and homogenization

[0228] According to the requirements, 2200 kg of pasteurized milk (dry matter 270 kg), 945 kg of skim milk (dry matter content 18%), and 625 kg of desalted whey liquid (dry matter content 20%) were fed into a vacuum mixer, and circulated at -0.9 bar and 45°C; during the process, 130 kg of edible vegetable blend oil (soybean oil, sunflower oil, coconut oil, flaxseed oil), 200 kg of lactose, 75 kg of galactooligosaccharides, 6 kg of calcium citrate, 5 kg of fructooligosaccharides, 1 kg of calcium hydrogen phosphate, 3 kg of vitamin premix (vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin, taurine), 2 kg of choline chloride, 2 kg of mineral premix (magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate, sodium selenite), and 1 kg of nutrient premix (lutein, inositol, L-carnitine) were added; the mixing time lasted for 45 min, then the mixed liquid was preheated to 55°C by a plate heat exchanger, homogenized at 240 bar, and cooled to 8°C by a plate heat exchanger after homogenization, and stored; the theoretical dry matter content of the above mixed liquid was 23.6%, and the actual dry matter content was 17.5% due to the presence of material and water during the production process, and about 1.5 tons of process water entered the mixed liquid during the production process.

[0229] 5. Evaporation and concentration

[0230] The mixed liquid was fed into an evaporator for concentration, and the operating conditions were as follows: DSI sterilization temperature 90°C, sterilization time 10s, primary vacuum degree -950 mbar, primary temperature of the first effect 70°C, primary temperature of the second effect 65°C, primary temperature of the third effect 60°C, and the outlet liquid concentration was controlled at 50%, obtaining the mixed material.

[0231] 6. Spray drying

[0232] The mixed material was preheated to 75°C, pumped into a drying tower by a high-pressure pump for spray drying, the inlet air temperature was 180°C, and the exhaust air temperature was 75°C, after secondary drying and cooling by a dynamic fluidized bed, the semi-finished powder was obtained, and stored in a powder bin.

[0233] 7. Dry mixing and packaging

[0234] Take 990 kg of semi-finished powder, 5 kg of docosahexaenoic acid oil powder (7%), 5 kg of arachidonic acid oil powder (10%) for dry mixing, and then fill into cans.

[0235] Comparative Example 2:

[0236] 1. Pasteurized milk preparation

[0237] The raw cow milk that has passed the acceptance test is preheated to 50℃, then sterilized and clarified by a milk clarifier, and then pasteurized at a temperature of 85℃ for 15s, with the outlet temperature controlled at 8℃.

[0238] 2. Mixing and homogenization

[0239] According to the requirements, 2200 kg of pasteurized milk (dry matter 270 kg) is pumped into a vacuum mixer, and the mixture is circulated and mixed at -0.9 bar and 45℃; during the process, 170 kg of skim milk powder, 125 kg of desalted whey powder, 130 kg of edible vegetable blend oil (soybean oil, sunflower oil, coconut oil, flaxseed oil), 200 kg of lactose, 75 kg of galacto-oligosaccharide, 6 kg of calcium citrate, 5 kg of fructo-oligosaccharide, 1 kg of calcium hydrogen phosphate, 3 kg of vitamin premix (vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin, taurine), 2 kg of choline chloride, 2 kg of mineral premix (magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate, sodium selenite), 1 kg of nutrient premix (lutein, inositol, L-carnitine); the mixing time lasts for 45 min, then the mixed liquid is preheated to 55℃ by a plate heat exchanger, homogenized at a pressure of 240 bar, and then cooled to 8℃ by a plate heat exchanger, enters a wet mixing tank, and is diluted to a dry matter content of 17.5% by adding water.

[0240] 3. Evaporation and concentration

[0241] The mixed liquid enters the evaporator for concentration, and the operating conditions are as follows: DSI sterilization temperature 90℃, sterilization time 10s, primary vacuum degree -950mbar, primary temperature of one effect 70℃, primary temperature of two effects 65℃, primary temperature of three effects 60℃, and the outlet liquid concentration is controlled at 50%, obtaining the mixed material.

[0242] 4. Spray drying

[0243] The mixed material is preheated to 75℃, pumped into a drying tower by a high-pressure pump for spray drying, with the inlet air temperature 180℃ and the exhaust air temperature 75℃, and after secondary drying and cooling by a dynamic fluidized bed, the semi-finished powder is obtained and temporarily stored in a powder bin.

[0244] 5. Dry mixing and packaging

[0245] Take 990 kg of semi-finished powder, 5 kg of docosahexaenoic acid oil powder (7%), 5 kg of arachidonic acid oil powder (10%) for dry mixing, and then fill into cans.

[0246] Comparative Example 3:

[0247] 1. Preparation of skimmed milk

[0248] The raw cow milk that has passed the acceptance test is preheated to 50°C, and then enters the separator for defatting at a speed of 5000 r / min. The fat content of the skimmed milk is required to be <0.1%, and the qualified skimmed milk is subjected to pasteurization at a temperature of 85°C for 15 s, and the outlet temperature is controlled at 8°C.

[0249] The skimmed milk after pasteurization is concentrated by RO membrane, the operating pressure is 25 bar, the dry matter content at the outlet is controlled at 18%, and the temperature is 8°C. The concentrated skimmed milk is temporarily stored in a milk tank.

[0250] 2. Preparation of pasteurized milk

[0251] The raw cow milk that has passed the acceptance test is preheated to 50°C, and then subjected to pasteurization after sterilization by a milk clarifier at a temperature of 85°C for 15 s, and the outlet temperature is controlled at 8°C.

[0252] 3. Mixing and homogenization

[0253] According to the requirements, 2200 kg of pasteurized milk (dry matter content 270 kg), 945 kg of skimmed milk (dry matter content 18%) are fed into a vacuum mixer, and the mixture is circulated and mixed at -0.9 bar and 50°C. During the process, 125 kg of desalted whey powder, 130 kg of edible vegetable blend oil (soybean oil, sunflower oil, coconut oil, flaxseed oil), 200 kg of lactose, 75 kg of galacto-oligosaccharide, 6 kg of calcium citrate, 5 kg of fructo-oligosaccharide, 1 kg of calcium hydrogen phosphate, 3 kg of vitamin premix (vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin, taurine), 2 kg of choline chloride, 2 kg of mineral premix (magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate, sodium selenite), and 1 kg of nutrient premix (lutein, inositol, L-carnitine) are added. The mixing time lasts for 45 min, and then the mixed liquid is preheated to 55°C by a plate heat exchanger, homogenized at a pressure of 240 bar, cooled to 8°C by a plate heat exchanger after homogenization, and stored in a wet mixing tank by adding water to a dry matter content of 17.5%.

[0254] 4. Evaporation and concentration

[0255] The mixed liquid enters the evaporator for concentration, and the operating conditions are as follows: DSI sterilization temperature 90°C, sterilization time 10s, one-effect body vacuum degree -950mbar, one-effect body temperature 70°C, two-effect body temperature 65°C, three-effect body temperature 60°C, and outlet liquid concentration controlled at 50%, to obtain the mixture.

[0256] 5. Spray drying

[0257] The mixture is preheated to 75°C, pumped into the drying tower by a high-pressure pump for spray drying, the inlet air temperature is 180°C, and the exhaust air temperature is 75°C. After secondary drying and cooling by a dynamic fluidized bed, the semi-finished powder is obtained and temporarily stored in a powder bin.

[0258] 6. Dry mixing and packaging

[0259] 990kg of semi-finished powder, 5kg of docosahexaenoic acid oil powder (7%), and 5kg of arachidonic acid oil powder (10%) are dry mixed, and then filled into cans.

[0260] Comparative Example 4:

[0261] 1. Preparation of membrane desalination whey

[0262] (1) Defatting of raw cow milk

[0263] The raw cow milk that has passed the acceptance test is preheated to 50°C, and then enters the separator for defatting at a rotation speed of 5000r / min, with the requirement that the fat content of the skim milk is <0.1%. The qualified skim milk is subjected to pasteurization at a temperature of 85°C for 15s, and the outlet temperature is controlled at 8°C.

[0264] (2) Microfiltration separation

[0265] The above-mentioned skim milk enters the microfiltration membrane to remove casein, to obtain whey; the microfiltration membrane is made of polyether sulfone material, the microfiltration membrane pore size is 0.1μm, the operating temperature is 15°C, and the operating pressure is 1.0bar.

[0266] (3) Ultrafiltration standardization

[0267] The whey obtained by microfiltration is subjected to ultrafiltration standardization, the ultrafiltration membrane is made of polyether sulfone material, the molecular weight cut-off of the ultrafiltration membrane is 5000-10000Da, the operating temperature is 15°C, and the protein content in the outlet liquid is controlled to reach 12% of the total solids.

[0268] (4) Nanofiltration concentration

[0269] The whey after ultrafiltration standardization is concentrated by a nanofiltration membrane, the molecular weight cut-off of the nanofiltration membrane is 100-500Da, the concentration multiple is about 5, and the operating temperature is 15°C; the solid content at the nanofiltration outlet is required to be 20%.

[0270] (5) Desalination by electrodialysis

[0271] The concentrated whey liquid is desalinated by electrodialysis, and the conductivity is reduced to 1.0 mS / cm to obtain desalinated whey; the electrodialysis operating temperature is 15°C, the initial voltage is 20V, and the operating pH is controlled at 6.5.

[0272] 2. Preparation of pasteurized milk

[0273] The raw cow milk that passes the acceptance test is first preheated to 50°C, then sterilized and clarified by a milk clarifier, and then pasteurized at a temperature of 85°C for 15s, with the outlet temperature controlled at 8°C.

[0274] 3. Mixing and homogenization

[0275] According to the requirements, 2200 kg of pasteurized milk (dry matter 270 kg) and 625 kg of desalinated whey liquid (dry matter content 20%) are fed into a vacuum mixer, and the mixture is circulated and mixed at -0.9 bar and 45°C; during the process, 170 kg of skimmed milk powder, 130 kg of edible vegetable blend oil (soybean oil, sunflower oil, coconut oil, flaxseed oil), 200 kg of lactose, 75 kg of galacto-oligosaccharides, 6 kg of calcium citrate, 5 kg of fructo-oligosaccharides, 1 kg of calcium hydrogen phosphate, 3 kg of vitamin premix (vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin, taurine), 2 kg of choline chloride, 2 kg of mineral premix (magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate, sodium selenite), and 1 kg of nutrient premix (lutein, inositol, L-carnitine) are added; the mixing time lasts for 45 min, then the mixed liquid is preheated to 55°C by a plate heat exchanger, homogenized at a pressure of 240 bar, cooled to 8°C by a plate heat exchanger after homogenization, and then stored in a wet mixing tank by adding water to a dry matter content of 17.5%.

[0276] 4. Evaporation and concentration

[0277] The mixed liquid is fed into an evaporator for concentration, and the operating conditions are as follows: DSI sterilization temperature 90°C, sterilization time 10s, primary vacuum degree -950 mbar, primary temperature of the first effect 70°C, primary temperature of the second effect 65°C, primary temperature of the third effect 60°C, and outlet liquid concentration controlled at 50%, to obtain a mixed material.

[0278] 5. Spray drying

[0279] The mixed material is preheated to 75°C, pumped into a drying tower by a high-pressure pump for spray drying, with an inlet air temperature of 180°C and an exhaust air temperature of 75°C, and after secondary drying and cooling by a dynamic fluidized bed, a semi-finished powder is obtained and stored in a powder bin.

[0280] 6. Dry blending packaging

[0281] Take 990 kg of semi-finished powder, 5 kg of docosahexaenoic acid oil powder (7%), 5 kg of arachidonic acid oil powder (10%) for dry blending, and then fill into cans.

[0282] Comparative Example 5:

[0283] 1. Preparation of skimmed milk

[0284] The raw cow milk that has passed the acceptance test is first preheated to 50℃, and then enters the separator to be defatted at a speed of 5000r / min. The fat content of the skimmed milk is required to be <0.1%, and the qualified skimmed milk is subjected to pasteurization at a temperature of 85℃ for 15s, and the outlet temperature is controlled at 8℃.

[0285] The skimmed milk after pasteurization is concentrated by RO membrane, the operating pressure is 25bar, the outlet dry matter is 8.4%, and the temperature is 8℃. The concentrated skimmed milk is stored in a tank.

[0286] 2. Preparation of membrane desalted whey

[0287] (1) Defatting of raw cow milk

[0288] The raw cow milk that has passed the acceptance test is first preheated to 50℃, and then enters the separator to be defatted at a speed of 5000r / min. The fat content of the skimmed milk is required to be <0.1%, and the qualified skimmed milk is subjected to pasteurization at a temperature of 85℃ for 15s, and the outlet temperature is controlled at 8℃.

[0289] (2) Microfiltration separation

[0290] The above skimmed milk enters the microfiltration membrane to remove casein to obtain whey. The microfiltration membrane is made of polyether sulfone material, the microfiltration membrane pore size is 0.1μm, the operating temperature is 15℃, and the operating pressure is 1.0bar.

[0291] (3) Ultrafiltration standardization

[0292] The whey obtained by microfiltration is subjected to ultrafiltration standardization. The ultrafiltration membrane is made of polyether sulfone material, the molecular weight cut-off of the ultrafiltration membrane is 5000-10000Da, the operating temperature is 15℃, and the protein content in the outlet liquid is controlled to be 12% of the total solids.

[0293] (4) Nanofiltration concentration

[0294] The whey after ultrafiltration standardization is concentrated by nanofiltration membrane. The molecular weight cut-off of the nanofiltration membrane is 100-500Da, the concentration multiple is about 2.5 times, the operating temperature is 15℃, and the solid content at the nanofiltration outlet is required to be 10%.

[0295] (5) Desalination by electrodialysis

[0296] The concentrated whey liquid is desalinated by electrodialysis, and the conductivity is reduced to 1.0 mS / cm to obtain desalinated whey; the electrodialysis operating temperature is 15°C, the initial voltage is 20V, and the operating pH is controlled at 6.5.

[0297] 3. Pasteurized milk preparation

[0298] The raw cow milk that has passed the acceptance test is preheated to 50°C, then sterilized and clarified by a milk clarifier, and then pasteurized at a temperature of 85°C for 15s, with the outlet temperature controlled at 8°C.

[0299] 4. Mixing and homogenization

[0300] According to the requirements, 2200 kg of pasteurized milk (dry matter 270 kg), 2023 kg of skimmed milk (dry matter content 8.4%), and 1250 kg of desalinated whey liquid (dry matter content 10%) are fed into a vacuum mixer, and circulated at -0.9 bar and 45°C; during the process, 130 kg of edible vegetable blend oil (soybean oil, sunflower oil, coconut oil, flaxseed oil), 200 kg of lactose, 75 kg of galacto-oligosaccharides, 6 kg of calcium citrate, 5 kg of fructo-oligosaccharides, 1 kg of calcium hydrogen phosphate, 3 kg of vitamin premix (vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin, taurine), 2 kg of choline chloride, 2 kg of mineral premix (magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate, sodium selenite), and 1 kg of nutrient premix (lutein, inositol, L-carnitine) are added; the mixing time lasts for 45 min, then the mixed liquid is preheated to 55°C by a plate heat exchanger, homogenized at a pressure of 240 bar, cooled to 8°C by a plate heat exchanger after homogenization, and stored; the above mixed liquid has a theoretical dry matter content of 15.9%, and due to the presence of material and water during the production process, the actual dry matter content is 12.8%, and about 1.5 tons of process water enters the mixed liquid during the production process.

[0301] 5. Evaporation concentration and spray drying

[0302] The mixed liquid enters the evaporator for concentration, and the operating conditions are as follows: DSI sterilization temperature 90°C, sterilization time 10s, primary effect vacuum degree -950 mbar, primary effect temperature 70°C, secondary effect temperature 65°C, tertiary effect temperature 60°C, and outlet liquid concentration controlled at 50%.

[0303] Since the current import feed liquid concentration is only 12.8%, in order to achieve the target of 40% of the export feed liquid concentration, it is necessary to reduce the evaporation inlet quantity and increase the hot pressure pump pressure. Although the water evaporation quantity per unit time can be increased by enhancing the evaporation intensity, it will lead to the increase of system energy consumption. At the same time, the reduction of the feed quantity leads to the decrease of dry matter input, and further leads to the synchronous reduction of the evaporation outlet material quantity, which cannot match the normal production of the drying tower and cannot guarantee the continuous operation. If the evaporation outlet liquid concentration is reduced to ensure that the evaporation outlet quantity and the drying tower feed quantity match, the material concentration entering the drying tower is too low. In order to achieve the drying effect and ensure continuous production, the air inlet temperature needs to be increased, but this will lead to: the material heat treatment intensity is large, the component particles are very fine, and the product is poor in brewing.

[0304] Comparative Example 6:

[0305] 1. Preparation of skimmed milk

[0306] The raw cow milk that has passed the acceptance test is preheated to 50℃, and then enters the separator to be defatted at a speed of 5000r / min. The fat content of the skimmed milk is required to be less than 0.1%. The qualified skimmed milk is subjected to pasteurization at a temperature of 85℃ for 15s, and the outlet temperature is controlled at 8℃.

[0307] The skimmed milk after pasteurization is concentrated by RO membrane at a running pressure of 25bar, and the dry matter at the outlet is 28% and the temperature is 8℃. The concentrated skimmed milk is temporarily stored in a milk tank.

[0308] 2. Preparation of desalted whey liquid by membrane method

[0309] (1) Defatting of raw cow milk

[0310] The raw cow milk that has passed the acceptance test is preheated to 45℃, and then enters the separator to be defatted at a speed of 5000r / min. The fat content of the skimmed milk is required to be less than 0.1%. The qualified skimmed milk is subjected to pasteurization at a temperature of 85℃ for 15s, and the outlet temperature is controlled at 8℃.

[0311] (2) Microfiltration separation

[0312] The above skimmed milk enters the microfiltration membrane to remove casein to obtain whey liquid. The microfiltration membrane is made of polyether sulfone material, the microfiltration membrane pore size is 0.1μm, the running temperature is 15℃, and the running pressure is 1.0bar.

[0313] (3) Ultrafiltration standardization

[0314] The whey liquid obtained by microfiltration is subjected to ultrafiltration standardization. The ultrafiltration membrane is made of polyether sulfone material, the molecular weight cut-off of the ultrafiltration membrane is 5000-10000Da, the running temperature is 15℃, and the protein content in the outlet liquid is controlled to be 12% of the total solid content.

[0315] (4) Nanofiltration concentration

[0316] The ultrafiltration standardized whey liquid is concentrated by a nanofiltration membrane, the molecular weight cut-off of the nanofiltration membrane is 100-500 Da, the concentration ratio is about 7 times, and the operation temperature is 15°C; the nanofiltration outlet requires that the solid content is 28%.

[0317] (5) Desalination by electrodialysis

[0318] The concentrated whey liquid is desalinated by electrodialysis, and the conductivity is reduced to 1.0 mS / cm to obtain desalinated whey; the electrodialysis operation temperature is 15°C, the initial voltage is 20V, and the operation pH is controlled at 6.5.

[0319] 3. Preparation of pasteurized milk

[0320] The raw cow milk that passes the acceptance test is preheated to 50°C, then sterilized and clarified by a milk clarifier, and then pasteurized at a temperature of 85°C for 15s, and the outlet temperature is controlled at 8°C.

[0321] 4. Mixing and homogenization

[0322] According to the requirements, 2200 kg of pasteurized milk (dry matter 270 kg), 607 kg of skimmed milk (dry matter content 28%), and 446 kg of desalinated whey (dry matter content 28%) are fed into a vacuum mixer, and the mixture is circulated at -0.9 bar and 45°C; During the process, 130 kg of edible vegetable blend oil (soybean oil, sunflower seed oil, coconut oil, flaxseed oil), 200 kg of lactose, 75 kg of galactooligosaccharides, 6 kg of calcium citrate, 5 kg of fructooligosaccharides, 1 kg of calcium hydrogen phosphate, 3 kg of vitamin premix (vitamin A, vitamin D, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, vitamin B12, vitamin C, niacin, folic acid, pantothenic acid, biotin, taurine), 2 kg of choline chloride, 2 kg of mineral premix (magnesium sulfate, ferric pyrophosphate, zinc sulfate, manganese sulfate, potassium iodate, copper sulfate, sodium selenite), 1 kg of nutrient premix (lutein, inositol, L-carnitine) are added; The mixing time lasts for 45 min, then the mixed liquid is preheated to 55°C by a plate heat exchanger, homogenized at a pressure of 240 bar, and then cooled to 8°C by a plate heat exchanger after homogenization, and stored; The theoretical dry matter content of the above mixed liquid is 27.9%, and the actual dry matter content is 21% due to the presence of material top water and water top material during the production process. About 1.5 tons of process water enters the mixed liquid during the production process.

[0323] 5. Evaporation concentration and spray drying

[0324] The mixed liquid enters the evaporator for concentration, and the operating conditions are as follows: DSI sterilization temperature 90°C, sterilization time 10s, one-effect vacuum degree-950mbar, one-effect temperature 70°C, two-effect temperature 65°C, three-effect temperature 60°C, and outlet liquid concentration controlled at 50%.

[0325] In the processing of infant formula milk powder, when the dry matter content in the mixed liquid reaches 21%, although it can meet the normal production needs of the evaporation concentration and spray drying processes, there are the following problems in the DSI sterilization process: due to the slightly high concentration of the material (dry matter content > 20%), the holding tube is prone to scorching at high temperature for a long time, which affects the product quality and safety, and the furan amino acid in the obtained product also increases. The reason may be that the high concentration of the mixed liquid entering the evaporator DSI sterilization process causes the protein and carbohydrate concentrations to be relatively high, resulting in a high degree of Maillard reaction. At the same time, the high concentration of skim milk and desalted whey liquid in the nanofiltration concentration process also has a series of problems such as high energy consumption, long production time, and shortened service life of the nanofiltration membrane.

[0326] Test Example

[0327] 1. Protein, furan amino acid, lysine content

[0328] The protein, lysine, furan amino acid, and protein content of the raw materials and products in each example and each comparative example were detected by the first method in GB5009.5, the furan amino acid content was detected according to the draft of the “National Food Safety Standard Determination of Furan Amino Acid in Milk Products” prepared by the National Health Commission of the People's Republic of China and the Beijing Institute of Animal Husbandry and Veterinary Medicine of the Chinese Academy of Agricultural Sciences and other units on December 2, 2021, and the amino acid content was detected according to GB5009.124. The results are shown in Table 1.

[0329] 2. Whey protein denaturation rate

[0330] The whey protein denaturation rate in the finished product of each example and each comparative example was determined (the results are shown in Table 1). The theoretical value of whey protein was calculated according to the proportion of whey protein in cow milk and raw milk whey and the amount of each protein raw material, so as to calculate the whey protein denaturation rate in the finished product. The detection method was Kjeldahl nitrogen determination. First, the finished milk powder was reconstituted at a certain proportion, frozen at about 4°C, and centrifuged to remove fat. Then, 1 mol / L hydrochloric acid solution was used to centrifuge and precipitate. The obtained supernatant (un-denatured whey protein solution) was reacted with a catalyst, distilled, and then titrated with hydrochloric acid after adding boric acid. The un-denatured whey protein content was calculated according to the amount of acid consumed, and the denaturation rate was calculated by the difference between the whey protein content in the mixed liquid and the finished powder. The calculation formula is as follows:

[0331] Table 1:

[0332] 3. Product reconstitution evaluation

[0333] Dissolution state detection: reconstitute the product according to the corresponding reconstitution ratio and water temperature, and then place a clean glass slide in the reconstituted emulsion for 1 min. Then, immerse 3 / 4 of the glass slide in the reconstituted emulsion, stir vigorously for 5 s (do not draw a circle), vertically take out the glass slide, tilt it at about 60° for 10 s, then wipe the back and bottom of the glass slide dry, and compare it with the standard version (as shown in FIG. 2) under sufficient light and black background. The reading time should not exceed 30 s. If the result is between two standards, record 0.5 units.

[0334] White spot detection: reconstitute the product according to the corresponding reconstitution ratio and water temperature, and then place a clean glass slide in the reconstituted emulsion for 1 min. Then, immerse 3 / 4 of the glass slide in the reconstituted emulsion, stir vigorously for 5 s (do not draw a circle), vertically take out the glass slide, tilt it at about 60° for 10 s, then wipe the back and bottom of the glass slide dry, and compare it with the standard version (as shown in FIG. 2) under sufficient light and black background. The reading time should not exceed 30 s. If the result is between two standards, record 0.5 units.

[0335] Product reconstitution evaluation score = dissolution state x 0.5 + white spot x 0.5, the higher the final score, the better the reconstitution (see Table 2).

[0336] Table 2:

[0337] The raw materials such as skimmed milk powder, desalted whey powder, and concentrated whey protein powder used in the current production process of infant formula milk powder often need to undergo a long storage period from production to actual use, which is several months at the shortest and one to two years at the longest. During the storage period, these raw materials will inevitably undergo a series of complex chemical and biological changes. However, due to the limitations of existing technical means, these changes are difficult to monitor comprehensively, resulting in insufficient guarantee of the freshness of the raw materials. In contrast, the use of full-liquid protein feed can completely avoid the storage period of powdered protein raw materials. This process effectively solves the problem of nutrient loss caused by multiple heat treatments and long-term storage in the traditional production of infant formula milk powder, thereby providing infants with fresher, safer, and more easily absorbed nutritional products, which is beneficial to the growth and development of infants.

[0338] The present application provides a preparation method of formula milk powder, which significantly improves the product quality through raw material system selection and process optimization. The specific technical solutions are as follows:

[0339] (1) Raw material system selection

[0340] The process route adopts full-liquid protein raw materials, especially, adopts membrane process to obtain defatted liquid milk and desalted liquid whey as part of raw materials, and abandons traditional high-heat treatment dry powder raw materials. The innovative scheme has the following advantages: 1) avoid multiple high-temperature treatment in raw material production link, significantly reduce the degree of Maillard reaction; 2) reduce protein thermal denaturation, maintain the natural conformation of whey protein; 3) eliminate the quality uncertainty caused by long-term storage of powder raw materials.

[0341] (2) Process optimization control

[0342] 1) By accurately controlling the dry matter content of desalted whey and defatted milk, energy consumption optimization is realized while ensuring process continuity;

[0343] 2) Adopting mild heat treatment parameters, maximize the retention of nutritional ingredients;

[0344] 3) Adopting vacuum mixing-evaporation concentration-spray drying integrated process to ensure product freshness.

[0345] (3) Product quality improvement

[0346] The content of Maillard reaction products (furan amino acid, etc.) in the product is reduced, the retention rate of essential amino acids (lysine) is increased, the denaturation rate of whey protein is controlled below 11%, the product is evenly dispersed without caking phenomenon, and the solubility is good.

[0347] It should be noted that although the technical solutions of the present application are introduced with specific examples, those skilled in the art can understand that the present application should not be limited thereto.

[0348] The above has described the embodiments of the present application, the above description is exemplary, not exhaustive, and is also not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The choice of terms used herein is intended to best explain the principles, practical application or technical improvement in the market of the embodiments, or to enable other ordinary skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method of preparing a formula milk powder, characterized in that, The method comprises: a mixing step of mixing a raw milk raw material liquid, a skim milk raw material liquid, a desalted whey raw material liquid, and optionally other allowable added temperature-sensitive components; a spray drying step of spray drying the mixture obtained in the mixing step to obtain a powder; In the mixing step: the raw milk raw material liquid is a pasteurized milk liquid directly from an animal; the skim milk raw material liquid is a milk liquid obtained by centrifugal skimming of animal milk; the desalted whey raw material liquid is a milk liquid obtained by whey separation and whey desalting of animal milk, and the whey separation is whey separation by membrane separation, and the whey desalting is removal of salt in whey by membrane separation; the denaturation rate of whey protein in the formula milk powder is 11% or less.

2. The method of claim 1, wherein, The raw milk raw material liquid, the skim milk raw material liquid, and the desalted whey raw material liquid are all from cow milk, goat milk, or horse milk.

3. The method according to claim 1 or 2, characterized in that, In the preparation of the skim milk raw material liquid: after centrifugal skimming, the skim milk raw material liquid is obtained by one or both of pasteurization and membrane concentration.

4. The method according to any one of claims 1 to 3, characterized in that, In the preparation of the desalted whey raw material liquid: the whey separation is carried out by microfiltration membrane treatment, and the whey desalting is carried out by electrodialysis treatment.

5. The method of claim 4, wherein, Between the microfiltration membrane treatment and the electrodialysis treatment, a nanofiltration membrane treatment process is further included to concentrate the whey liquid to be electrodialyzed.

6. The method according to any one of claims 1 to 5, characterized in that, After the spray drying to obtain the powder, the powder is mixed with optional other allowable added temperature-sensitive components.

7. The method according to any one of claims 1 to 6, characterized in that, The mixing step includes a homogenization process.

8. The method according to any one of claims 1 to 7, characterized in that, Between the mixing step and the spray drying step, one or both of a composition adjustment step and a sterilization step are further included.

9. The method according to any one of claims 1-8, characterized in that: the dry matter content of the skim milk raw material liquid is 9-25% by mass, and the fat content is 0.1% by mass or less; the conductivity of the desalted whey raw material liquid is 1.5 mS / cm or less; the dry matter content of the mixture to be spray dried is 40-60% by mass.

10. The method according to any one of claims 1 to 9, characterized in that, The content of furfuryl amino acid in the formula milk powder is 500 mg / 100 g of protein or less.

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