A preparation process for improving lactose crystallinity in infant formula milk powder

Abstract

The application belongs to the technical field of milk powder preparation, and particularly relates to a preparation process for improving lactose crystallinity in infant formula milk powder. The preparation process adds alpha-lactose monohydrate in the concentrated process before spray drying in the production of infant formula milk powder, and combines the optimization of the addition amount of alpha-lactose monohydrate, the concentration of concentrated milk and the temperature of concentrated milk to control the content of crystalline lactose in the concentrated milk solution, so as to accurately control the lactose crystallinity in the infant formula milk powder, and finally obtain high-quality infant formula milk powder with specific lactose crystallization characteristics, improve the storage stability of the product, break through the limitation that the traditional process cannot control the lactose crystallinity, fill the technical gap in the field, and provide a flexible and feasible technical scheme for improving the powder characteristics of infant formula milk powder.

Description

Technical Field

[0001] This invention belongs to the field of milk powder preparation technology, specifically relating to a preparation process for improving the crystallinity of lactose in infant formula milk powder. Background Technology

[0002] Infant formula, as the primary source of nutrition for infants' growth and development, has powder characteristics that directly affect its reconstitution properties and storage stability. Lactose crystallinity is one of the main factors influencing these characteristics. Currently, infant formula production typically uses fresh milk as the main raw material, involving ingredient formulation, homogenization, concentration, sterilization, and spray drying. While control is primarily focused on microbial content, nutrient retention, and moisture content, effective measures for controlling lactose crystallinity during production are lacking. Infant formula produced using traditional methods typically has a lactose crystallinity of 2-4%, leading to poor powder flowability, poor resistance to compression, and a tendency to absorb moisture and clump during storage.

[0003] In the production of infant formula, lactose mainly exists in two crystalline forms: monohydrate α-lactose and anhydrous β-lactose. Its content is affected by the temperature and concentration of the feed solution. Furthermore, because the spray drying process is much shorter than the time required for lactose molecules to arrange themselves into orderly crystals, the dried finished milk powder primarily exists in an amorphous form with irregular molecular arrangement and no fixed lattice structure. Without effective control, the crystallinity of lactose remains at a low level. Too low a crystallinity results in poor powder flowability and resistance to extrusion, and during storage, it easily leads to moisture absorption and clumping, exacerbating the Maillard reaction and fat oxidation in the milk powder. Conversely, too high a crystallinity may reduce the solubility (wetting and dispersibility) of the milk powder. By systematically studying the changes in the form and state of lactose in each process of ingredient preparation, homogenization, concentration, sterilization and spray drying, as well as the correlation between the addition process, amount, concentration and temperature of lactose in production and the crystallinity of lactose, a preparation process to improve the crystallinity of lactose in infant formula milk powder was invented. This process improves the extrusion resistance and flowability of infant formula milk powder, and also helps to improve the hygroscopic resistance of milk powder, thereby enhancing the storage stability of milk powder.

[0004] Existing technology CN 115644242 A, while proposing a technical solution to improve the storage stability of infant formula milk powder, focuses on obtaining milk powder slurries with different lactose crystallinity by cooling the infant formula powder solution in an ice-water bath, followed by spray drying to obtain infant formula milk powder with different lactose crystallinity, and then determining the optimal storage temperature and humidity by combining different temperature and humidity storage conditions. Furthermore, existing technology CN 120694305 A, based on existing infant formula milk powder, improves the glass transition temperature (T0) of milk powder by pre-crystallizing lactose during the ingredient preparation process. The core of this approach is to increase the concentration of concentrated milk and raise the inlet and outlet air temperatures and the secondary drying temperature of the fixed fluidized bed, thereby reducing the free water content and increasing the glass transition temperature (T0). g This effectively improves the anti-caking ability of infant formula. Existing technology CN 115644242 A describes obtaining milk powder slurries with different lactose crystallinities by cooling concentrated milk at low temperatures and stirring for a long time, followed by spray drying to obtain infant formula with different lactose crystallinities. However, this method involves relatively complex production operations.

[0005] Clearly, the technical approaches and control methods employed in the existing technologies described above are significantly different from the technical solution of this invention, which achieves precise control of lactose crystallinity by regulating the addition of monohydrate α-lactose in concentrated milk before spray drying and by rationally controlling key parameters such as the concentration and temperature of the concentrated milk. In summary, under the current technological background, no research has yet addressed an innovative preparation process that optimizes the lactose addition process and amount during infant formula production to regulate lactose crystallinity in infant formula, thereby improving the hygroscopic resistance, storage stability, compression resistance, and flowability of infant formula. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of this invention is to design a technical solution for improving the crystallinity of lactose in infant formula milk powder.

[0007] The technical solution adopted in this invention is as follows: The first aspect of this invention provides a preparation process for improving the crystallinity of lactose in infant formula milk powder, comprising the following steps: 1) Mix whole milk powder, skim milk powder, concentrated whey protein powder, edible vegetable blended oil, soybean lecithin, galactooligosaccharides, fructooligosaccharides, α-lactose monohydrate and premix online until the materials are evenly mixed, without any gritty feeling, and the oil is evenly dispersed. 2) Homogenize and concentrate the mixture obtained in step 1) to obtain concentrated milk; 3) Add α-lactose monohydrate to the concentrated milk obtained in step 2), stir gently, and then spray dry to obtain infant formula milk powder with improved lactose crystallinity.

[0008] Furthermore, the ingredients of the infant formula milk powder are as follows: 20.0~25.0 g / 100g whole milk powder, 0~13.0 g / 100g skim milk powder, 6.0~9.0 g / 100g concentrated whey protein powder, 9.5~19.5 g / 100g edible vegetable blended oil, 0.3~0.5 g / 100g soybean lecithin, 0~1.2 g / 100g galactooligosaccharides, 0~1.5 g / 100g fructooligosaccharides, 40.0~60.0 g / 100g α-lactose monohydrate, and 0.7~1.3 g / 100g premix.

[0009] Further, in step 1), the mixing temperature is 40 ~ 45 ℃, the mixing shearing speed is 2000 ~ 4000 rpm, and the mixing time is 15 ~ 30 min.

[0010] Furthermore, the homogenization pressure in step 2) is controlled at 20~22 MPa.

[0011] Furthermore, in step 2), the final concentration of the concentrated milk is 45-55 wt%, and the temperature is 35℃-45℃.

[0012] Further, in step 3), the amount of α-lactose monohydrate added is 1 to 7 wt%, and the stirring speed is 400 to 600 rpm.

[0013] Furthermore, in step 3), the feed temperature of the spray-dried liquid is 35-45°C, the air inlet temperature is 150-200°C, and the exhaust temperature is 85-95°C.

[0014] The second aspect of the present invention provides an infant formula milk powder with improved lactose crystallinity prepared by the above-described preparation process.

[0015] Furthermore, the milk powder has a lactose crystallinity of 6% to 10%, a moisture content of ≤2.80%, a water activity of ≤0.17, a compression ratio of 15% to 20%, and a Carr index of 50 to 55.

[0016] The beneficial effects of this invention include: Based on the existing production process of infant formula, a portion of α-lactose monohydrate is added in the concentrated milk process, and the concentration and temperature of the concentrated milk are optimized to control the content of crystalline lactose in the concentrated milk liquid, thereby achieving precise control of the lactose crystallinity in infant formula. This breakthrough overcomes the limitations of traditional processes in controlling lactose crystallinity, filling a technological gap in the field and providing a flexible and feasible technical solution for improving the powder properties of infant formula, while reducing production upgrade costs. Attached Figure Description

[0017] Figure 1 The process flow diagram of this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to specific embodiments. However, it should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0019] In the concentration process before spray drying in infant formula production, α-lactose monohydrate is added. By optimizing parameters such as the amount of α-lactose monohydrate added, the concentration of concentrated milk, and the temperature of the concentrated milk, the crystallinity of lactose in the milk powder is controlled, ultimately obtaining high-quality infant formula with specific lactose crystallization characteristics and improving the product's storage stability. The specific preparation process is as follows: Figure 1 As shown, it includes the following steps: 1) Ingredients: Mix whole milk powder with other raw and auxiliary materials online at a temperature of 40-45℃, a shearing speed of 3000rpm, and a mixing time of 15-30 minutes. Ensure the materials are mixed evenly, without any gritty feeling, and that the oil is evenly dispersed.

[0020] Ingredient composition (g / 100g): Whole milk powder 20.0 ~ 25.0; Skim milk powder 0 ~ 13.0; Concentrated whey protein powder 6.0 ~ 9.0; Edible vegetable blended oil: 9.5 ~ 19.5; Soybean lecithin 0.3 ~ 0.5; Galacto-oligosaccharides: 0 ~ 1.2; Fructooligosaccharides: 0-1.5%; α-Lactose monohydrate 40.0 ~ 60.0; Premixed feed 0.7 ~ 1.3.

[0021] 2) Homogenization: Homogenization pressure is controlled at 20 ~ 22 MPa.

[0022] 3) Concentration: Pump the liquid into the evaporator to remove some of the water from the liquid, and control the final concentrated milk concentration at 45~55 wt% and the temperature at 35℃~45℃.

[0023] 4) Addition of lactose monohydrate: After adding lactose monohydrate to the concentrated liquid, stir gently at a stirring speed of 500 rpm. The amount of α-lactose monohydrate added is 1 ~ 7 wt%.

[0024] 5) Spray drying: The feed temperature is controlled at 35 ~ 45℃, the air inlet temperature is controlled at 180℃, and the exhaust temperature is controlled at 90℃ by controlling the feed rate.

[0025] Explanation of technical terms in this invention: 1) Glassy state: The molecular thermal energy of the material is very low, and the molecular chains and chain segments are in a frozen state. At this time, the mechanical properties are similar to those of glass.

[0026] 2) Rubber state: The material can deform when subjected to external force, and can return to its original shape after the external force is removed, exhibiting a highly elastic state.

[0027] 3) Lactose crystallinity: The proportion of lactose in milk powder that exists in an ordered, stable crystalline form.

[0028] 4) α-Lactose monohydrate: Lactose is a stable solid that crystallizes regularly in a monoclinic system and is stoichiometrically bound to a water molecule. The molecules are highly ordered and the structure is dense. It exists in a variogram equilibrium in aqueous solution, but the crystal form itself is stable.

[0029] 5) Anhydrous β-lactose: Lactose crystallizes or dehydrates under high temperature conditions to form a solid form without water of crystallization. Its molecules are arranged in a β-configuration, and the crystal structure is usually fine needle-like or plate-like. It has a higher dissolution rate and hygroscopicity.

[0030] 6) Anhydrous α-lactose: It has a compact crystal structure and its thermodynamic stability is between that of metastable anhydrous β-lactose and stable monohydrate α-lactose.

[0031] 7) Compressibility: The ratio of the difference between tapped density and loose density to tapped density. The ideal compressibility for infant formula is 15-20%.

[0032] 8) Carr index: also known as flowability index, it integrates angle of repose, angle of plate, cohesion, and compressibility. It uses angle of repose, angle of plate, cohesion, and compressibility as basic characteristics, and indexes each characteristic value and sums them to characterize the flow properties of powder. The higher the Carr index, the better the flowability.

[0033] The present invention will be further illustrated below with reference to the embodiments.

[0034] Example 1 1) Ingredients: Mix whole milk powder with other raw and auxiliary materials online at a temperature of 40-45℃, a shearing speed of 3000rpm, and a mixing time of 15-30 minutes. Ensure the materials are mixed evenly, without any gritty feeling, and that the oil is evenly dispersed.

[0035] Ingredient composition (g / 100g): Whole milk powder 20.0; Concentrated whey protein powder 9.0; Edible vegetable blended oil 19.5; Soybean lecithin 0.5; Galacto-oligosaccharides 1.0; Fructooligosaccharides 1.0; α-Lactose monohydrate 60.0; Premixed feed 1.3.

[0036] 2) Homogenization: Homogenization pressure is controlled at 20 MPa.

[0037] 3) Concentration: Pump the liquid into the evaporator to remove some of the water from the liquid, and control the final concentrated milk concentration at 55wt% and the temperature at 45℃.

[0038] 4) Addition of lactose monohydrate: After adding lactose monohydrate to the concentrated liquid, stir gently at a speed of 500 rpm. The amount of α-lactose monohydrate added is 1 wt%.

[0039] 5) Spray drying: The feed temperature is controlled at 45℃, the air inlet temperature is controlled at 180℃, and the exhaust temperature is controlled at 90℃ by controlling the feed rate.

[0040] Example 2

[0041] 1) Ingredients: Mix whole milk powder with other raw and auxiliary materials online at a temperature of 40-45℃, a shearing speed of 3000rpm, and a mixing time of 15-30 minutes. Ensure the materials are mixed evenly, without any gritty feeling, and that the oil is evenly dispersed.

[0042] Ingredient composition (g / 100g): Whole milk powder 22.0; Skim milk powder 11.0; Concentrated whey protein powder 8.0; Edible vegetable blended oil 14.7; Soybean lecithin 0.4; Galacto-oligosaccharides 1.0; Fructooligosaccharides 1.0; α-Lactose monohydrate 44; Premix 1.0.

[0043] 2) Homogenization: Homogenization pressure is controlled at 20 MPa.

[0044] 3) Concentration: Pump the liquid into the evaporator to remove some of the water from the liquid, and control the final concentrated milk concentration at 45wt% and the temperature at 40℃.

[0045] 4) Addition of lactose monohydrate: After adding lactose monohydrate to the concentrated liquid, stir gently at a stirring speed of 500 rpm. The amount of α-lactose monohydrate added is 4 wt%.

[0046] 5) Spray drying: The feed temperature is controlled at 40℃, the air inlet temperature is controlled at 180℃, and the exhaust temperature is controlled at 90℃ by controlling the feed rate.

[0047] Example 3

[0048] 1) Ingredients: Mix whole milk powder with other raw and auxiliary materials online at a temperature of 40-45℃, a shearing speed of 3000rpm, and a mixing time of 15-30 minutes. Ensure the materials are mixed evenly, without any gritty feeling, and that the oil is evenly dispersed.

[0049] Ingredient composition (g / 100g): Whole milk powder 25.0; Skim milk powder 13.0; Concentrated whey protein powder 6.0; Edible vegetable blended oil 13.0; Soybean lecithin 0.3; Galacto-oligosaccharides 1.0; Fructooligosaccharides 1.0; α-Lactose monohydrate 40.0; Premix 1.0.

[0050] 2) Homogenization: Homogenization pressure is controlled at 20 MPa.

[0051] 3) Concentration: Pump the liquid into the evaporator to remove some of the water from the liquid, and control the final concentrated milk concentration at 45wt% and the temperature at 45℃.

[0052] 4) Addition of lactose monohydrate: After adding lactose monohydrate to the concentrated liquid, stir gently at a stirring speed of 500 rpm. The amount of α-lactose monohydrate added is 7 wt%.

[0053] 5) Spray drying: The feed temperature is controlled at 45℃, the air inlet temperature is controlled at 180℃, and the exhaust temperature is controlled at 90℃ by controlling the feed rate.

[0054] Comparative Example 1 1) Ingredients: Mix whole milk powder with other raw and auxiliary materials online at a temperature of 40-45℃, a shearing speed of 3000rpm, and a mixing time of 15-30 minutes. Ensure the materials are mixed evenly, without any gritty feeling, and that the oil is evenly dispersed.

[0055] Ingredient composition (g / 100g): Whole milk powder 20.0; Concentrated whey protein powder 9.0; Edible vegetable blended oil 19.5; Soybean lecithin 0.5; Galacto-oligosaccharides 1.0; Fructooligosaccharides 1.0; α-Lactose monohydrate 60.0; Premixed feed 1.3.

[0056] 2) Homogenization: Homogenization pressure is controlled at 20 MPa.

[0057] 3) Concentration: Pump the liquid into the evaporator to remove some of the water from the liquid, and control the final concentrated milk concentration at 42wt% and the temperature at 35℃.

[0058] 4) Addition of lactose monohydrate: After adding lactose monohydrate to the concentrated liquid, stir gently at a speed of 500 rpm. The amount of α-lactose monohydrate added is 1 wt%.

[0059] 5) Spray drying: The feed temperature is controlled at 35℃, the air inlet temperature is controlled at 180℃, and the exhaust temperature is controlled at 90℃ by controlling the feed rate.

[0060] Comparative Example 2 1) Ingredients: Mix whole milk powder with other raw and auxiliary materials online at a temperature of 40-45℃, a shearing speed of 3000rpm, and a mixing time of 15-30 minutes. Ensure the materials are mixed evenly, without any gritty feeling, and that the oil is evenly dispersed.

[0061] Ingredient composition (g / 100g): Whole milk powder 22.0; Skim milk powder 11.0; Concentrated whey protein powder 8.0; Edible vegetable blended oil 14.7; Soybean lecithin 0.4; Galacto-oligosaccharides 1.0; Fructooligosaccharides 1.0; α-Lactose monohydrate 44.0; Premix 1.0.

[0062] 2) Homogenization: Homogenization pressure is controlled at 20 MPa.

[0063] 3) Concentration: Pump the liquid into the evaporator to remove some of the water from the liquid, and control the final concentrated milk concentration at 57wt% and the temperature at 35℃.

[0064] 4) Addition of lactose monohydrate: After adding lactose monohydrate to the concentrated liquid, stir gently at a stirring speed of 500 rpm. The amount of α-lactose monohydrate added is 4 wt%.

[0065] 5) Spray drying: The feed temperature is controlled at 35℃, the air inlet temperature is controlled at 180℃, and the exhaust temperature is controlled at 90℃ by controlling the feed rate.

[0066] Comparative Example 3 1) Ingredients: Mix whole milk powder with other raw and auxiliary materials online at a temperature of 40-45℃, a shearing speed of 3000rpm, and a mixing time of 15-30 minutes. Ensure the materials are mixed evenly, without any gritty feeling, and that the oil is evenly dispersed.

[0067] Ingredient composition (g / 100g): Whole milk powder 25.0; Skim milk powder 13.0; Concentrated whey protein powder 6.0; Edible vegetable blended oil 13.0; Soybean lecithin 0.3; Galacto-oligosaccharides 1.0; Fructooligosaccharides 1.0; α-Lactose monohydrate 40.0; Premixed feed 0.7.

[0068] 2) Homogenization: Homogenization pressure is controlled at 20 MPa.

[0069] 3) Concentration: Pump the liquid into the evaporator to remove some of the water from the liquid, and control the final concentrated milk concentration at 50 wt% and the temperature at 30 ℃.

[0070] 4) Addition of lactose monohydrate: After adding lactose monohydrate to the concentrated liquid, stir gently at a speed of 500 rpm. The amount of α-lactose monohydrate added is 9 wt%.

[0071] 5) Spray drying: The feed temperature is controlled at 30℃, the air inlet temperature is controlled at 180℃, and the exhaust temperature is controlled at 90℃ by controlling the feed rate.

[0072] Comparative Example 4 1) Ingredients: Mix whole milk powder with other raw and auxiliary materials online at a temperature of 40-45℃, a shearing speed of 3000rpm, and a mixing time of 15-30 minutes. Ensure the materials are mixed evenly, without any gritty feeling, and that the oil is evenly dispersed.

[0073] Ingredient composition (g / 100g): Whole milk powder 20.0; Concentrated whey protein powder 9.0; Edible vegetable blended oil 19.5; Soybean lecithin 0.5; Galacto-oligosaccharides 1.0; Fructooligosaccharides 1.0; α-Lactose monohydrate 60.0; Premixed feed 1.3.

[0074] 2) Homogenization: Homogenization pressure is controlled at 20 MPa.

[0075] 3) Concentration: Pump the liquid into the evaporator to remove some of the water from the liquid, and control the final concentrated milk concentration at 55wt% and the temperature at 35℃.

[0076] 4) Lactose monohydrate: Not added.

[0077] 5) Spray drying: The feed temperature is controlled at 35℃, the air inlet temperature is controlled at 180℃, and the exhaust temperature is controlled at 90℃ by controlling the feed rate.

[0078] The test results for each formulation in the examples and comparative examples are shown in Table 1: Table 1 Test Results Lactose crystallinity (%) 6 7 9 4 18 21 2 Moisture content (%) 2.80 2.50 2.25 2.58 2.62 2.40 2.70 water activity 0.17 0.14 0.09 0.15 0.16 0.12 0.19 Compression rate (%) 20 18 17 22.00 13.33 14.33 25.00 Carr indicator 50.50 53.50 54.00 47.00 55.00 56.60 45.00 .

Claims

1. A preparation process for improving the crystallinity of lactose in infant formula milk powder, characterized in that, Includes the following steps: 1) Mix whole milk powder, skim milk powder, concentrated whey protein powder, edible vegetable blended oil, soybean lecithin, galactooligosaccharides, fructooligosaccharides, α-lactose monohydrate and premix online until the materials are evenly mixed, without any gritty feeling, and the oil is evenly dispersed. 2) Homogenize and concentrate the mixture obtained in step 1) to obtain concentrated milk; 3) Add α-lactose monohydrate to the concentrated milk obtained in step 2), stir gently, and then spray dry to obtain infant formula milk powder with improved lactose crystallinity.

2. The preparation process according to claim 1, characterized in that, The infant formula milk powder contains the following ingredients: 20.0-25.0 g / 100g whole milk powder, 0-13.0 g / 100g skim milk powder, 6.0-9.0g / 100g concentrated whey protein powder, 9.5-19.5 g / 100g edible vegetable blended oil, 0.3-0.5 g / 100g soybean lecithin, 0-1.2 g / 100g galactooligosaccharides, 0-1.5 g / 100g fructooligosaccharides, 40.0-60.0 g / 100g α-lactose monohydrate, and 0.7-1.3 g / 100g premix.

3. The preparation process according to claim 1, characterized in that, Step 1) The mixing temperature is 40 ~ 45 ℃, the mixing shearing speed is 2000 ~ 4000 rpm, and the mixing time is 15 ~ 30 min.

4. The preparation process according to claim 1, characterized in that, Step 2) The homogenization pressure is controlled at 20 ~ 22 MPa.

5. The preparation process according to claim 1, characterized in that, Step 2) The final concentration of the concentrated milk is 45-55 wt%, and the temperature is 35℃-45℃.

6. The preparation process according to claim 1, characterized in that, Step 3) The amount of α-lactose monohydrate added is 1 to 7 wt%, and the stirring speed is 400 to 600 rpm.

7. The preparation process according to claim 1, characterized in that, Step 3) The feed temperature of the spray-dried liquid is 35 ~ 45℃, the air inlet temperature is 150 ~ 200℃, and the exhaust temperature is 85 ~ 95℃.

8. Infant formula milk powder with improved lactose crystallinity prepared by any one of the preparation processes described in claims 1-7.

9. The infant formula milk powder as described in claim 8, characterized in that, The milk powder has a lactose crystallinity of 6% to 10%, a moisture content of ≤2.80%, a water activity of ≤0.17, a compression ratio of 15% to 20%, and a Carr index of 50 to 55.

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