Preparation method of fat globule structure emulsion with interface containing all main milk fat globule membrane proteins

Abstract

The invention provides a preparation method of a fat globule structure emulsion with an interface containing all main milk fat globule membrane proteins, which comprises the following steps: preparing cream rich in large fat globules and reconstructing the fat globules, the step of preparing the cream rich in the large fat globules comprises a step of preparing cow milk rich in the large fat globules and a step of separating the cream; the fat globule reconstruction step comprises the following steps: mixing the cream rich in large fat globules obtained in the cream separation step with a milk fat globule membrane material water solution, and then preheating and homogenizing. According to the invention, the breast milk oil-in-water emulsion can be simulated from the interface protein molecule level.

Description

Technical Field

[0001] The invention belongs to the technical field of fat globule structured emulsions, in particular to a method for preparing a fat globule structured emulsion containing all major milk fat globule membrane proteins at the interface, so as to simulate breast milk oil-in-water emulsion at the interface protein molecule level. Background Art

[0002] Infant formula is the only suitable substitute for breast milk. However, the processing technology of infant formula (including homogenization, heat sterilization and spray drying) results in the fat globule interface composition in milk powder being very different from that in breast milk.

[0003] For the formula whose basic raw material is whole milk, homogenization seriously destroys the structure of natural milk fat globule membrane, and therefore causes the loss of milk fat globule membrane material and the large amount of adsorption of casein and whey protein (mainly β-lactoglobulin and α-lactalbumin) at the fat globule interface. Heat sterilization and spray drying can cause casein and whey protein to further bind to the fat globule interface. For the formula whose basic raw material is skim milk, since skim milk does not contain original fat globules, casein and whey protein are homogenized with mixed vegetable oil to obtain fat globules wrapped by casein and whey protein. Heat sterilization and spray drying can also cause casein and whey protein to further bind to the fat globule interface. Therefore, the main components of the interface of fat globules in infant formula milk powder are casein and whey protein.

[0004] The breast milk fat globule interface contains a large number of membrane proteins, including xanthine oxidoreductase (XO), fatty acid binding protein (FABP), fat droplet binding protein (ADPH), butyrophilin (BTN), tissue glycoprotein periodic acid Schiff IV (CD 36), tissue glycoprotein periodic acid Schiff 6 / 7 (PAS 6 / 7), tissue glycoprotein periodic acid Schiff III (PASIII) and mucin I (MUC 1), while casein and whey protein are less. Therefore, it is extremely important to greatly reduce the adsorption of milk protein on the fat globule interface and increase the concentration and types of membrane proteins on the interface.

[0005] Recently, many researchers have used commercially available milk fat globule membrane raw materials to encapsulate mixed vegetable oils by homogenization. This preparation method is a conventional method for the preparation of fat globule structured emulsions. However, previous studies have found that the types of major milk fat globule membrane proteins at the interface of water-in-oil emulsions are not as many as those in breast milk, and only contain CD36, BTN and ADPH. This is because the separation process of commercially available milk fat globule membrane raw materials will lead to the release of some milk fat globule membrane proteins loosely bound to the membrane, such as XO, PASIII, PAS 6 / 7 and MUC 1. Therefore, it is of great significance to construct a fat globule structured emulsion that is closer to the protein composition of the breast milk fat interface by adjusting the components.

[0006] The inventors have found that as a lipid source with a high fat content, cream may have more natural milk fat globule membrane materials due to its relatively simple enrichment process and the presence of a certain amount of water phase. At the same time, cream can provide a natural membrane framework for the reconstruction of fat globules in emulsions. In addition, fat globules with larger particle sizes contain more membrane proteins. Therefore, the present invention obtains fat globules with more major milk fat globule membrane proteins through fat globule particle size screening, thereby regulating the interface protein composition of fat globules.

[0007] Through searching, no patent publications related to simulating breast milk oil-in-water emulsion at the interface protein molecule level have been found. Summary of the invention

[0008] The purpose of the present invention is to address the deficiencies of the prior art and provide a method for preparing a fat globule structured emulsion containing all major milk fat globule membrane proteins at the interface, aiming to simulate breast milk oil-in-water emulsion at the interface protein molecule level.

[0009] The technical solution adopted by the present invention to solve the technical problem is:

[0010] The invention discloses a method for preparing a fat globule structured emulsion whose interface contains all main milk fat globule membrane proteins. The oil phase of the fat globule structured emulsion is cream rich in large fat globules, and the water phase is an aqueous solution of milk fat globule membrane materials.

[0011] Furthermore, the mass percentages of the components of the fat globule structured emulsion are: 1.29% cream, 4.26% milk fat globule membrane material, and 94.45% water.

[0012] Furthermore, in the technology of the fat globule structured emulsion, after the oil phase and the water phase are mixed, there is no need to use a high-speed shearing machine for pre-emulsification, and only preheating and homogenization are required.

[0013] The method for preparing the fat globule structured emulsion whose interface contains all the main milk fat globule membrane proteins as described above comprises the following steps:

[0014] (1) dissolving the milk fat globule membrane material in distilled water, stirring and hydrating to obtain a milk fat globule membrane material aqueous solution for later use;

[0015] (2) After the raw milk is centrifuged for the first time, the upper layer of milk is taken to obtain milk rich in large fat globules for later use;

[0016] (3) further centrifuging the milk rich in large fat globules obtained in step (2), taking the upper layer of cream to obtain cream rich in large fat globules for later use;

[0017] (4) The milk fat globule membrane material aqueous solution prepared in step (1) and the cream rich in large fat globules prepared in step (3) are mixed, and then preheated and homogenized in sequence to obtain the fat globule structure emulsion.

[0018] 5. Furthermore, in step (1), 4.26 g of milk fat globule membrane material was dissolved in 94.45 g of distilled water and stirred with a magnetic stirrer (600 rpm, 50° C.) for hydration overnight.

[0019] 6. Furthermore, in step (2), 250 mL of raw milk is centrifuged for the first time at 350×g for 5 min at room temperature, and the top 20 mL of solution is taken, which is the milk rich in large fat globules.

[0020] 7. Furthermore, in the step (3), the milk rich in large fat globules is preheated at 40° C. and then further centrifuged at room temperature to obtain the top layer of cream, which is the cream rich in large fat globules, wherein the centrifugal speed of the further centrifugation is 4000 rpm and the centrifugal time is 5 min.

[0021] 8. Furthermore, the preheating temperature in step (4) is 50°C, the total homogenization pressure is 20 MPa, and the homogenization is performed 3 times in total.

[0022] It can be seen from the above technical solutions that, compared with the prior art, the emulsion with a fat globule structure containing all the main milk fat globule membrane proteins at the interface provided by the present invention and the preparation method thereof have the following excellent effects:

[0023] 1. Based on previous research, the present invention simulates the breast milk fat globule interface at the protein molecule level. Compared with the fat globule structured emulsion prepared by conventional methods, the fat globule structured emulsion interface prepared by the present invention contains all the main fat globule membrane proteins and has a higher relative abundance.

[0024] 2. Compared with the fat globule structured emulsion prepared by conventional methods, the fat globule structured emulsion prepared by the present invention has a higher interfacial protein carrying capacity, smaller and more stable fat globule particle size, and the most types of interfacial proteins.

[0025] 3. In the present invention, the butter rich in large fat globules is used as the oil phase, which can improve the adsorption of proteins in the milk fat globule membrane material (aqueous phase) in the preparation of the fat globule structure emulsion.

[0026] 4. The present invention does not require high-speed shear pre-emulsification in terms of processing technology, which simplifies the production process of fat globule structure emulsion, reduces production energy consumption and costs, and the required raw materials are easy to obtain and can be obtained from commercial channels, so it is easier to process and obtain. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention and the superior effects of the present invention compared with the fat globule structured emulsion (control example) prepared by the conventional method, the following is a brief introduction to the drawings required for use in the fat globule structured emulsion prepared in the embodiments and the control example.

[0028] Figure 1 A comparison diagram of the particle sizes of the fat globule structured emulsion prepared in the present invention and the fat globule structured emulsion prepared in the reference example;

[0029] Figure 2 A comparison chart of the stability constants of the fat globule structured emulsion prepared in the present invention and the fat globule structured emulsion prepared in the reference example;

[0030] Figure 3 A comparison chart of the interface loading capacity of the fat globule structured emulsion prepared in the present invention and the fat globule structured emulsion prepared in the reference example;

[0031] Figure 4 A comparison diagram of the types of interface proteins of the fat globule structured emulsion prepared in the present invention and the fat globule structured emulsion prepared in the reference example;

[0032] Figure 5 A comparison diagram of the relative abundance of major fat globule membrane proteins on the interface of the fat globule structured emulsion prepared in the present invention and the fat globule structured emulsion prepared in the control example; DETAILED DESCRIPTION

[0033] For a better understanding of the present invention, the present invention is further described in detail below in conjunction with embodiments and comparative examples, but the scope of protection claimed by the present invention is not limited to the scope represented by the embodiments.

[0034] The raw materials used in the examples and reference examples of the present invention, unless otherwise specified, are conventional commercially available products, and the methods used in the examples and reference examples of the present invention, unless otherwise specified, are conventional methods in the art.

[0035] Example 1

[0036] Example 1 discloses a method for preparing a fat globule structured emulsion having an interface containing all major milk fat globule membrane proteins, comprising the following steps:

[0037] Step 1: Dissolve 4.26 g of milk fat globule membrane material in 94.45 g of distilled water, stir and hydrate overnight with a magnetic stirrer (600 rpm, 50° C.) to obtain a milk fat globule membrane material solution;

[0038] Step 2: Centrifuge 250 mL of raw milk at 350 × g for 5 min at room temperature, and take the top 20 mL of solution, which is the milk rich in large fat globules;

[0039] Step 3: preheat the milk rich in large fat globules (40°C) and centrifuge it at 4000 rpm for 5 minutes at room temperature, and take the top layer of cream, which is the cream rich in large fat globules;

[0040] Step 4: Mix the milk fat globule membrane material solution prepared in step 1 and the large fat globule-rich cream (1.29 g) prepared in step 3, preheat at 50° C. and homogenize at 20 MPa for 3 times to obtain the fat globule structure emulsion.

[0041] Comparative Example 1

[0042] Comparative Example 1 discloses a conventional method for preparing a fat globule structured emulsion containing milk fat globule membrane protein at the interface, as a control for Example 1, comprising the following steps:

[0043] Step 1: dissolve 0.013 g of milk protein and 4.267 g of milk fat globule membrane material in 94.72 g of distilled water, stir and hydrate overnight with a magnetic stirrer (600 rpm, 50° C.) to obtain a protein aqueous solution (aqueous phase);

[0044] Step 2: melt 1 g of anhydrous butter at 60° C., mix with the protein aqueous solution prepared in step 1, and pre-emulsify with a high-speed shearing machine (10,000 rpm, 50° C.) to obtain a pre-emulsified emulsion;

[0045] Step 3: preheat the pre-emulsified emulsion prepared in step 2 to 50° C. and homogenize at 20 MPa for 3 times to obtain a fat globule structured emulsion containing milk fat globule membrane protein at its interface prepared by a conventional method.

[0046] Depend on Figure 1 It can be seen that the particle size of the fat globules in the emulsion prepared by the present invention is significantly lower than that of the emulsion prepared by the conventional method (p < 0.05), indicating that the natural membrane structure remaining on the fat globule membrane in the cream rich in large fat globules after homogenization can improve the emulsification performance of the emulsion.

[0047] Depend on Figure 2 It can be seen that the stability coefficient of the fat globules in the emulsion prepared by the present invention is significantly lower than that of the emulsion prepared by the conventional method (p < 0.05), indicating that the fat globules in the emulsion prepared by the present invention are more stable. This result may be because the natural structure of the fat globule membrane on the interface of the fat globules in the emulsion prepared by the present invention helps to improve the stability of the emulsion.

[0048] Depend on Figure 3 It can be seen that the interfacial carrying capacity of fat globules in the emulsion prepared by the present invention is significantly higher than that of the emulsion prepared by the conventional method (p < 0.05), indicating that the natural membrane structure retained on the fat globule membrane in the cream rich in large fat globules after homogenization has affinity for the protein in the milk fat globule membrane material.

[0049] Depend on Figure 4 It can be seen that compared with the emulsion prepared by the conventional method, the emulsion prepared by the present invention contains more types of interfacial proteins.

[0050] Depend on Figure 5 It can be seen that the average total relative abundance of the major milk fat globule membrane proteins separated from the interface of the emulsion prepared by the present invention is 4.7E+10, which is much higher than the major milk fat globule membrane proteins (9.9E+7) separated from the interface of the emulsion prepared by the conventional method. The interface of the emulsion prepared by the present invention contains all the major milk fat globule membrane proteins, but the interface of the emulsion prepared by the conventional method does not contain FABP, and MUC 1, BTN, CD 36, and PAS III are all below the instrument detection limit.

[0051] Although the embodiments and comparative examples of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A fat globule structured emulsion having an interface containing all major milk fat globule membrane proteins, characterized in that: The oil phase of the fat globule structured emulsion is cream rich in large fat globules, and the water phase is an aqueous solution of milk fat globule membrane material.

2. The fat globule structured emulsion according to claim 1, characterized in that: The mass percentages of the components of the fat globule structure emulsion are: 1.29% of butter, 4.26% of milk fat globule membrane material, and 94.45% of water.

3. The fat globule structured emulsion according to claim 1, characterized in that: After the oil phase and the water phase are mixed, there is no need to use a high-speed shear machine for pre-emulsification, only preheating and homogenization are required.

4. A method for preparing the fat globule structured emulsion according to any one of claims 1 to 3, characterized in that: The method specifically comprises the following steps: (1) dissolving the milk fat globule membrane material in distilled water, stirring and hydrating to obtain a milk fat globule membrane material aqueous solution for later use; (2) After the raw milk is centrifuged for the first time, the upper layer of milk is taken to obtain milk rich in large fat globules for later use; (3) further centrifuging the milk rich in large fat globules obtained in step (2), taking the upper layer of cream to obtain cream rich in large fat globules for later use; (4) The milk fat globule membrane material aqueous solution prepared in step (1) and the cream rich in large fat globules prepared in step (3) are mixed, and then preheated and homogenized in sequence to obtain the fat globule structure emulsion.

5. The preparation method according to claim 4, characterized in that: In the step (1), 4.26 g of milk fat globule membrane material was dissolved in 94.45 g of distilled water, and stirred and hydrated overnight using a magnetic stirrer (600 rpm, 50° C.).

6. The preparation method according to claim 4, characterized in that: In the step (2), 250 mL of raw milk is centrifuged for the first time at 350×g for 5 min at room temperature, and 20 mL of the top layer solution is taken, which is the milk rich in large fat globules.

7. The preparation method according to claim 4, characterized in that: In the step (3), the milk rich in large fat globules is preheated at 40° C. and then further centrifuged at room temperature to obtain the top layer of cream, which is the cream rich in large fat globules. The centrifugal speed of the further centrifugation is 4000 rpm and the centrifugal time is 5 min.

8. The preparation method according to claim 4, characterized in that: The preheating temperature in the step (4) is 50° C., the total homogenization pressure is 20 MPa, and the homogenization is performed 3 times in total.

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