Children liquid milk and sterilization and preparation method thereof

Abstract

The invention relates to the technical field of dairy products, in particular to liquid milk for children and a sterilization and preparation method thereof. When the liquid milk for children is prepared, the pressure of the dynamic ultrahigh-pressure microjet is 150-200MPa, the holding time is 12-15s, an emulsifier used in the liquid milk for children comprises mono-and diglycerol fatty acid ester, polyglycerol fatty acid ester and propylene glycol fatty acid ester, and the emulsifier accounts for 0.06-0.12% of the liquid milk for children by mass. The liquid milk obtained by adopting the compound emulsifier and the microjet treatment condition provided by the invention is uniform in color and luster; the tissue state is a uniform fluid, and the phenomena of precipitation, clots, impurities, viscosity and thickness are avoided; the beverage has the fragrance of cow milk, is delicious and sweet in taste, and does not have any other abnormal taste.

Description

[0001] This application is a divisional application of the patent application filed on August 15, 2024, with application number 202411119110.X and invention title "A children's liquid milk and its sterilization and preparation method". Technical Field

[0002] This invention relates to the field of dairy product technology, and in particular to a children's liquid milk and its sterilization and preparation method. Background Technology

[0003] Children are in a crucial stage of growth and development, requiring ample nutrition to support the normal development of their bodily functions. Milk is rich in protein, fat, carbohydrates, vitamins, and minerals, which can help children grow healthily. In addition to providing the five major nutrients, milk also provides bioactive substances such as immunoglobulins, lactoferrin, and α-lactalbumin, which play an important role in the development and health of the human gut function and immune system.

[0004] However, most of the bioactive substances in milk are heat-sensitive and easily deactivated by heat, thus requiring sophisticated processing techniques. Currently, most children's milk on the market is UHT milk, with some products also fortified with vitamins, minerals, and other nutrients. However, high-temperature sterilization can cause the loss or even complete deactivation of these bioactive substances, resulting in nutritional deficiencies. Summary of the Invention

[0005] For children's liquid milk, ensuring the preservation of original active nutrients, as well as product quality, safety, and shelf-life stability, presents a huge challenge for dairy companies.

[0006] The purpose of this invention is to provide a liquid milk for children that, while ensuring product safety, can retain more of the bioactive substances in milk.

[0007] This invention proposes a sterilization method for children's liquid milk, and through the combined use of emulsifiers, effectively constructs the product emulsification system. While ensuring the stability of the product system and improving the product's taste, it can also improve the unpleasant flavor caused by mineral elements such as iron and zinc.

[0008] In a first aspect, the present invention provides a children's liquid milk, wherein the pressure of the dynamic ultra-high pressure microjet is 150-200 MPa and the maintenance time is 12-15 s during the preparation of the children's liquid milk, and the emulsifier used in the children's liquid milk includes: mono- and diglyceride fatty acid esters, polyglyceride fatty acid esters and propylene glycol fatty acid esters, and the emulsifier used accounts for 0.06-0.12% of the children's liquid milk by mass.

[0009] In the children's liquid milk provided by the present invention, the weight ratio of mono- and diglyceride fatty acid esters, polyglyceride fatty acid esters, and propylene glycol fatty acid esters in the emulsifier is (1-1.5):(1-2):1.5.

[0010] In preparing the children's liquid milk provided by the present invention, the collision angle of the dynamic ultra-high pressure microjets is coaxial and equal.

[0011] The formula of the children's liquid milk of the present invention includes: 80-98 parts by weight of raw milk, 0.07-0.24 parts by weight of HMOs, 0.08-0.12 parts by weight of compound iron and zinc powder, 0.06-0.12 parts by weight of emulsifier and water.

[0012] In the children's liquid milk provided by the present invention, the HMOs include one or more of 2'-fucosylated lactose, 3-fucosylated lactose, lactose-N-tetrasaccharide, lactose-N-neotetrasaccharide, 3'-sialylated lactose, or 6'-sialylated lactose.

[0013] The compound iron-zinc powder used in this invention is sourced from Shanghai Licheng Nutrition Technology Co., Ltd.

[0014] Secondly, the present invention provides a method for preparing the above-mentioned children's liquid milk, including: centrifugal sterilization, mixing, mixing temperature adjustment, energy storage, dynamic ultra-high pressure microjet and cooling filling; the mixing temperature adjustment includes: stirring at 3000r / min-8500r / min for 10-15min, and adjusting the liquid temperature to 32-42℃.

[0015] The purpose of mixing and temperature adjustment is: 1) to ensure the effectiveness of milk processing and help retain bioactive nutrients: bioactive nutrients in milk, such as lactoferrin, are lost to varying degrees above 50℃. In order to ensure the effectiveness of milk processing, the processing temperature needs to be maintained at 50-60℃. Therefore, after processing a small portion of milk in this temperature range, it is mixed with the majority of cold milk for temperature adjustment, which helps to retain more bioactive nutrients; 2) to reduce energy consumption: using partial milk processing consumes less energy than using all milk processing.

[0016] In the method for preparing children's liquid milk provided by the present invention, the rotation speed for centrifuging and sterilizing raw cow's milk is 4000 r / min-5000 r / min.

[0017] The preparation method of children's liquid milk provided by the present invention includes the following mixing process: taking 5-15% of the mass of the children's liquid milk, raw milk, HMOs, emulsifier and compound iron and zinc powder and mixing them evenly, the mixing conditions are 50-60℃, 10-15min, 3000r / min-8500r / min, to obtain liquid A.

[0018] As a specific embodiment of the present invention, the present invention provides a method for preparing children's liquid milk. (1) Centrifugation sterilization: The raw milk is first centrifuged at a speed of 4000 r / min - 5000 r / min; (2) Mixing: Take 5-15 portions of raw milk, HMOs, emulsifier, and compound iron-zinc powder that have been centrifuged and sterilized in step (1) and mix them evenly. The mixing conditions are 50-60℃, 10-15min, 3000r / min-8500r / min to obtain liquid A. (3) Mixing and temperature adjustment: Mix liquid A with the remaining centrifuged and sterilized raw milk, then add water to make up to 100 parts by weight and stir. The stirring conditions are 10-15 min, 3000 r / min-8500 r / min, and adjust the temperature to 32-42℃ to obtain liquid B. (4) Energy storage: The feed liquid B is stored in an ultra-high pressure pump to obtain the pressure required for dynamic ultra-high pressure micro-jet; (5) Dynamic ultra-high pressure micro jet: The liquid material B is subjected to jet collision at 150-200MPa with the collision angle being coaxial and equal, which converts the mechanical energy of the liquid material B into kinetic energy, forming a high-speed jet, and releasing energy through collision while simultaneously increasing the temperature. (6) Cooling and filling: Cool the liquid B after step (5) to 2-6℃ and fill it.

[0019] Thirdly, in the sterilization method of the above-mentioned children's liquid milk provided by the present invention, the children's liquid milk is sterilized by using dynamic ultra-high pressure microjet, wherein the pressure of the dynamic ultra-high pressure microjet is 150-200MPa, the collision angle is coaxial and equal, and the maintenance time is 12-15s.

[0020] In the sterilization method for children's liquid milk provided by the present invention, the emulsifier used in the children's liquid milk includes: mono- and diglyceride fatty acid esters, polyglyceride fatty acid esters and propylene glycol fatty acid esters, and the emulsifier used accounts for 0.06-0.12% of the children's liquid milk by mass.

[0021] The beneficial effects of this invention are as follows: (1) The liquid milk obtained by this invention has the effect of being rich in both basic nutrients and active nutrients. Active nutrients refer to nutrients that can perform specific functions after entering the human body. Compared with ordinary nutrients, active nutrients are more easily absorbed and utilized by the human body and play an important role in promoting health. However, active nutrients are usually more sensitive to environmental factors such as temperature and light, so special attention needs to be paid to maintain their activity during processing and storage.

[0022] Immunoglobulins and lactoferrin in fresh milk are bioactive nutrients that are easily deactivated at high temperatures. Because commercially available room-temperature liquid milk for children strives for ultimate safety, it loses these bioactive nutrients during the sterilization process.

[0023] This invention provides a novel sterilization method for children's liquid milk, which can sterilize while homogenizing. Specifically, this invention uses a dynamic ultra-high pressure microjet to treat the liquid for 12-15 seconds at a pressure of 150-200 MPa, which significantly reduces the number of microorganisms in the liquid; at the same time, it has a smaller impact on the activity of active nutrients such as lactoferrin, immunoglobulins, α-lactalbumin, and β-lactoglobulin in the liquid.

[0024] (2) The present invention provides a compound emulsifier that has the best effect when used with dynamic ultra-high pressure micro-jet treatment, and also provides the optimal dosage of the compound emulsifier.

[0025] (3) The liquid milk obtained by using the formula and preparation process provided by the present invention has a uniform color; the texture is a uniform fluid, without sediment, clots and impurities, and without viscosity or thickness; it has the aroma of milk, tastes delicious and sweet, and has no other abnormal taste. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0027] Example 1: A liquid milk for children The formula for the children's liquid milk provided in this embodiment, based on 100 parts by weight, is as follows: 80 parts by weight of raw milk, 0.07 parts by weight of HMOs, 0.08 parts by weight of compound iron and zinc powder, and 0.06 parts by weight of emulsifier (of which the ratio of mono- and diglyceride fatty acid esters, polyglyceride fatty acid esters, and propylene glycol fatty acid esters is 1:1:1.5), with the remainder made up with water.

[0028] The process for the children's liquid milk provided in this embodiment is as follows: (1) Centrifugation sterilization: The raw milk is first centrifuged at a speed of 4000 r / min; (2) Mixing: Take 5 portions of raw milk, HMOs, emulsifier and compound iron and zinc powder that have been centrifuged and sterilized in step (1) and mix them evenly. The mixing conditions are 60℃, 15min and 6000r / min to obtain liquid A. (3) Mixing and temperature adjustment: Mix liquid A with the remaining centrifuged and sterilized raw milk, then add water to make up to 100 parts by weight and stir. The stirring conditions are 15 min, 6000 r / min, and the temperature is adjusted to 32℃ to obtain liquid B. (4) Energy storage: The feed liquid B is stored in an ultra-high pressure pump to obtain the pressure required for dynamic ultra-high pressure micro-jet; (5) Dynamic ultra-high pressure micro-jet: Dynamic ultra-high pressure of 200MPa is used to jet collision of liquid B, and the collision angle is coaxial and equal. (6) Cooling and filling: Cool the liquid B after step (5) to 2-6℃ and fill it.

[0029] Example 2 The formula for the children's liquid milk provided in this embodiment is the same as that in Example 1, based on 100 parts by weight.

[0030] The difference between the process of children's liquid milk provided in this embodiment and that in embodiment 1 is: (3) When mixing and adjusting the temperature, the temperature is adjusted to 36°C to obtain liquid B; Step (5) Dynamic ultra-high pressure micro jet: Dynamic ultra-high pressure of 180MPa is used for liquid B.

[0031] Example 3 The formula for the children's liquid milk provided in this embodiment, based on 100 parts by weight, is as follows: 80 parts by weight of raw milk, 0.24 parts by weight of HMOs, 0.12 parts by weight of compound iron and zinc powder, 0.12 parts by weight of emulsifier (of which mono- and diglyceride fatty acid esters, polyglyceride fatty acid esters, and propylene glycol fatty acid esters are in a ratio of 1:1:1.5), with the remainder made up with water.

[0032] The difference between the process of children's liquid milk provided in this embodiment and that in embodiment 1 is: (3) When mixing and adjusting the temperature, the temperature is adjusted to 40°C to obtain liquid B; Step (5) Dynamic ultra-high pressure micro jet: Dynamic ultra-high pressure of 160MPa is used for liquid B.

[0033] Example 4 The formula for the children's liquid milk provided in this embodiment is the same as that in Example 3, based on 100 parts by weight.

[0034] The difference between the process of children's liquid milk provided in this embodiment and that in embodiment 3 is: (3) When mixing and adjusting the temperature, the temperature is adjusted to 42°C to obtain liquid B; Step (5) Dynamic ultra-high pressure micro jet: Dynamic ultra-high pressure of 150MPa is used for liquid B.

[0035] Comparative Example 1 Based on 100 parts by weight, the difference between the formula of the children's liquid milk provided in this comparative example and that in Example 1 is: 0.04 parts by weight of emulsifier (of which the ratio of mono- and diglyceride fatty acid esters, polyglyceride fatty acid esters, and propylene glycol fatty acid esters is 1:1:1.5).

[0036] The process for the children's liquid milk provided in this comparative example is the same as that in Example 1.

[0037] Comparative Example 2 The difference between the formulation of the children's liquid milk provided in this comparative example and that in Example 1, based on 100 parts by weight, is that the propylene glycol fatty acid ester in the emulsifier is replaced with triglyceride monostearate.

[0038] The process for the children's liquid milk provided in this comparative example is the same as that in Example 1.

[0039] Comparative Example 3 The formula of the children's liquid milk provided in this comparative example is the same as that in Example 1, based on 100 parts by weight.

[0040] The difference between the process of the children's liquid milk provided in this comparative example and Example 1 is that: step (5) dynamic ultra-high pressure micro-jet: dynamic ultra-high pressure of 250MPa is used for liquid B.

[0041] Comparative Example 4 The formula of the children's liquid milk provided in this comparative example is the same as that in Example 1, based on 100 parts by weight.

[0042] The difference between the process of the children's liquid milk provided in this comparative example and Example 1 is that: Step (5) Dynamic ultra-high pressure micro-jet: Dynamic ultra-high pressure of 120MPa is used for liquid B.

[0043] Comparative Example 5 The formula of the children's liquid milk provided in this comparative example is the same as that in Example 1, based on 100 parts by weight.

[0044] The process for the children's liquid milk provided in this comparative example is as follows: (1) Centrifugation sterilization: The raw milk is first centrifuged at a speed of 4000 r / min; (2) Mixing: Take 5 portions of raw milk, HMOs, emulsifier and compound iron and zinc powder that have been centrifuged and sterilized in step (1) and mix them evenly. The mixing conditions are 60℃, 15min and 6000r / min to obtain liquid A. (3) Mixing and temperature adjustment: Mix liquid A with the remaining centrifuged and sterilized raw milk, then add water to make up to 100 parts by weight and stir. The stirring conditions are 15 min, 6000 r / min, and the temperature is adjusted to 32℃ to obtain liquid B. (4) For liquid B, conventional homogenization and pasteurization processes were used. The homogenization pressure was 200 MPa and the pasteurization conditions were 72°C and 15 s.

[0045] (5) Cooling and filling: Cool the liquid B after step (4) to 2-6℃ and fill it.

[0046] Experiment Example 1: Sensory Testing The effects of the children's liquid milk provided in the embodiments and comparative examples of this invention on color, texture, odor, and taste were tested. Thirty personnel with relevant research and development experience were selected as sensory evaluators to score the samples. 30ml of each sample was placed in a plastic cup and randomly numbered. Simultaneously, each sample was rinsed with warm water during tasting to eliminate interference between samples. Specific scoring criteria and evaluation results are shown in the table below: Sensory evaluation results: Experimental Example 2: Detection of Active Substances The contents of lactoferrin, immunoglobulins, α-lactalbumin, and β-lactoglobulin in the children's liquid milk provided in the embodiments and comparative examples of the present invention were detected, and the results are as follows.

[0047] Stability Analysis of Experiment Example 3 The stability of the children's liquid milk provided in the embodiments and comparative examples of this invention was determined by using a stability analysis system (TURBISCAN TOWER) to detect the TSI (temperature 4°C, scan time 24h). The higher the TSI value, the worse the stability of the system. The test results are as follows.

[0048] Example 4 Microbial Detection The total bacterial count, coliform bacteria, Salmonella, and Staphylococcus aureus counts in the children's liquid milk provided in the embodiments and comparative examples of this invention were detected, and the results are shown in the table below.

[0049] The results of the experimental examples show that (1) the dynamic ultra-high pressure microjet provided by the present invention can effectively reduce the number of microorganisms in liquid emulsions and play a bactericidal role while homogenizing. The bactericidal effect of the dynamic ultra-high pressure microjet in the present invention also depends on the selection of dynamic ultra-high pressure intensity. When the dynamic ultra-high pressure intensity is small, the bactericidal effect is very limited; while excessive dynamic ultra-high pressure intensity will affect the activity of nutrients in liquid emulsions and affect the stability of the product.

[0050] (2) While the dynamic ultra-high pressure microjet provided by this invention controls the number of microorganisms in the liquid emulsion, it also introduces unstable factors into the liquid emulsion. This invention solves the problem of instability in the liquid emulsion after dynamic ultra-high pressure microjet processing by adjusting the formulation of the liquid emulsion, thus achieving a synergistic effect. Specifically, this invention selects compound emulsifiers, including mono- and diglycerides of fatty acids, polyglycerol fatty acid esters, and propylene glycol fatty acid esters, and limits the amount of compound emulsifiers added to 0.06-0.12% of the liquid emulsion.

[0051] (3) The liquid milk obtained by using the formula and preparation process provided by the present invention has a uniform color; the texture is a uniform fluid, without sediment, clots and impurities, and without viscosity or thickness; it has the aroma of milk, tastes delicious and sweet, and has no other abnormal taste.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid milk for children, characterized in that, When preparing the children's liquid milk, the pressure of the dynamic ultra-high pressure microjet is 150-200 MPa, and the maintenance time is 12-15 s. The emulsifiers used in the children's liquid milk include mono- and diglyceride fatty acid esters, polyglyceride fatty acid esters, and propylene glycol fatty acid esters. By mass, the emulsifiers used account for 0.06-0.12% of the children's liquid milk.

2. The children's liquid milk according to claim 1, characterized in that, The weight ratio of mono- and diglyceride fatty acid esters, polyglyceride fatty acid esters, and propylene glycol fatty acid esters in the emulsifiers used is (1-1.5):(1-2):1.

5.

3. The children's liquid milk according to claim 1, characterized in that, The collision angles of the dynamic ultra-high pressure microjets are coaxial and equal.

4. The children's liquid milk according to any one of claims 1-3, characterized in that, The formula for the children's liquid milk includes: raw milk, HMOs, compound iron and zinc powder, emulsifier, and water; Preferably, the mixture comprises: 80-98 parts by weight of raw milk, 0.07-0.24 parts by weight of HMOs, 0.08-0.12 parts by weight of compound iron and zinc powder, 0.06-0.12 parts by weight of emulsifier, and water.

5. The children's liquid milk according to claim 4, characterized in that, The HMOs include one or more of the following: 3-fucosylated lactose, lactose-N-tetrasaccharide, 3'-sialylated lactose, or 6'-sialylated lactose.

6. The method for preparing children's liquid milk according to any one of claims 1-5, characterized in that, include: Centrifugal sterilization, mixing, mixing temperature control, energy storage, dynamic ultra-high pressure microjet and cooling filling; Preferably, the mixing temperature adjustment involves adjusting the liquid temperature to 32-42℃; more preferably, the mixing temperature adjustment conditions further include stirring at 3000r / min-8500r / min for 10-15min.

7. The preparation method according to claim 6, characterized in that, The centrifugation speed for sterilizing raw milk is 4000 r / min-5000 r / min.

8. The preparation method according to claim 6, characterized in that, The mixing process includes: taking 5-15% of the mass of the children's liquid milk, raw milk, and mixing it evenly with HMOs, emulsifiers, and compound iron and zinc powder, with the mixing conditions being 50-60℃, to obtain liquid A; Preferably, the mixing conditions also include 10-15 min and 3000 r / min-8500 r / min.

9. The sterilization method for children's liquid milk according to any one of claims 1-5, characterized in that, The children's liquid milk is sterilized using a dynamic ultra-high pressure microjet. The pressure of the dynamic ultra-high pressure microjet is 150-200 MPa, the collision angle is coaxial and equal, and the maintenance time is 12-15 seconds.

10. The sterilization method according to claim 9, characterized in that, The emulsifiers used in the children's liquid milk include mono- and diglycerides of fatty acids, polyglycerides of fatty acids, and propylene glycol fatty acid esters, and the emulsifiers used account for 0.06-0.12% of the children's liquid milk by mass.

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