CN110771893A - Method for preparing β-carotene uniform emulsion by whey protein isolate glycosylation reaction product and uniform emulsion - Google Patents

Abstract

The invention discloses a method and a uniform emulsion for preparing a β-carotene uniform emulsion by a whey protein isolate glycosylation reaction product. The method comprises the following steps: 1) preparation of whey protein isolate glycosylation reaction product; 2) preparation of glycosylated protein-polyphenol complex; 3) preparation of β-carotene uniform emulsion. The good emulsifying properties and interface properties of the glycosylated protein-polyphenol nanocomposite of the present invention can effectively inhibit the coalescence phenomenon between oil droplets, so that the emulsion droplets show good uniformity, and the uniformity of the emulsion droplets and the storage stability D. At the same time, the glycosylation reaction causes the protein to form a denser and thicker interfacial layer outside the oil droplets loaded with active substances, which inhibits the interaction between active substances and pro-oxidants (metal ions, free radicals, dissolved oxygen).

Description

Preparation of β-carotene homogeneous emulsion from a whey protein isolate glycosylation reaction product method and uniform emulsion

technical field

The invention belongs to the technical field of food science and engineering, and more particularly relates to a method for preparing a beta-carotene uniform emulsion from a whey protein isolate glycosylation reaction product and the uniform emulsion.

Background technique

The technical scheme of the invention belongs to the technical field of food science and engineering, and particularly relates to a method for preparing a β-carotene uniform emulsion from a whey protein isolate glycosylation reaction product.

Protein-polysaccharide complexes can be formed through electrostatic interactions or covalent bonds, however, only covalently linked complexes are more stable in severe environments. Protein-polysaccharide complexes prepared by glycosylation reactions are highly tolerant to changes in pH, temperature, and particle strength, and inhibit proteolytic reactions and oxidation. Beta-carotene, a naturally occurring, highly lipophilic carotenoid synthesized by photosynthetic biosynthesis in plants, algae and cyanobacteria, has received increasing attention for its various health-promoting benefits. However, due to its extremely low water solubility, chemical and metabolic instability, and poor biological activity in vivo, the application of β-carotene in food, especially in nutraceutical-fortified foods, has been hindered. Owing to the advantages of biocompatibility and simple preparation process, the delivery system of oil-in-water (O/W) emulsions has been widely developed and used to protect β-carotene from isomerization, oxidation and degradation, etc., but conventional The proteoglycan emulsion embedding system is easily affected by the processing technology, and the stability of the emulsion is affected by the external environment. It is easy to aggregate and cause the precipitation of active substances in the emulsion. The antioxidant inhibitory effect of the emulsion on the active substances is reduced, and the bioavailability of the active substances is further reduced. .

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the above-mentioned problems. By adopting the stable homogeneous emulsion embedding system of glycosylated whey protein isolate-polyphenol nanocomposite, the degradation stability of β-carotene in the homogeneous emulsion can be significantly improved, and the emulsion can be effectively prolonged. The degradation time of the active substance is improved, and the tolerance of the emulsion embedding system in a complex environment is improved, and a simple method for improving the bioavailability of the active substance is provided.

In order to achieve the above object, a first aspect of the present invention provides a method for preparing a β-carotene uniform emulsion from a whey protein isolate glycosylation reaction product, the method comprising the following steps:

1) Preparation of whey protein isolate glycosylation reaction product

Mix whey protein isolate with D-(+) lactose and water to obtain a mixed solution of whey protein isolate and D-(+) lactose, adjust the pH of the mixed solution to 6.5-7.5, freeze-dry to obtain a protein-lactose mixture powder; the protein-lactose mixed powder is placed in an environment with a humidity of 70% to 79% and a temperature of 65°C to 70°C to react to obtain glycosylated whey protein isolate powder;

2) Preparation of glycosylated protein-polyphenol complexes

Mix the glycosylated whey protein isolate powder with water to obtain a glycosylated whey protein isolate solution, add epigallocatechin gallate powder, adjust the pH of the solution to 3.0-3.3, and mix thoroughly until the mixed solution becomes milky white obtaining the glycosylated protein-polyphenol complex;

3) Preparation of β-carotene homogeneous emulsion

Dissolving β-carotene in the oil phase, removing insoluble matter by centrifugation to obtain a β-carotene solution, and then mixing the β-carotene solution with the glycosylated protein-polyphenol complex in step 2) to obtain the Beta-carotene homogeneous emulsion.

According to the present invention, the water usually adopts experimental water commonly used by those skilled in the art, including but not limited to deionized water.

According to the present invention, the pH of the system can be adjusted by using acid-base regulators conventionally used by those skilled in the art. As in step 1), sodium hydroxide solution can be used to adjust the pH of the system to 6.5-7.5; as in step 2), hydrochloric acid solution can be used to adjust the pH of the system to 3.0-3.3.

As a preferred solution, the stirring can be carried out by means of magnetic stirring, and ensure that the substances are fully dissolved.

As a preferred solution, in step 1), the mass ratio of whey protein isolate to D-(+) lactose is 1:1-2.

As a preferred solution, in step 1), in the mixed solution of whey protein isolate and D-(+) lactose, the total mass of whey protein isolate and D-(+) lactose is 5% to 10%.

As a preferred solution, in step 1), the reaction time is 12h～24h.

As a preferred solution, in step 2), in the glycosylated whey protein isolate solution, the concentration of glycosylated whey protein isolate is 4 mg/mL-6 mg/mL.

As a preferred solution, in step 2), the mass ratio of glycosylated whey protein isolate powder to epigallocatechin gallate is 1-2:1-2.

As a preferred solution, in step 3), the concentration of β-carotene in the β-carotene solution is 0.05% to 0.1%.

As a preferred solution, in step 3), the mass ratio of the β-carotene solution and the glycosylated protein-polyphenol complex is 6-7:3-4.

As a preferred solution, in step 3), the rotational speed of the centrifugation is 10000rpm～12000rpm, and the time is 10min～15min.

As a preferred solution, in step 3), the rotation speed of the homogenization is 7500rpm～15000rpm, and the time is 2min～3min.

As a preferred solution, in step 3), the oil phase can be rapeseed oil, peanut oil, soybean oil, etc., preferably medium chain fatty acid glyceride (MCT).

A second aspect of the present invention provides a homogeneous emulsion prepared by the method described above.

According to the present invention, the volume fraction of the emulsion phase of the homogeneous emulsion is about 90% to 100%.

Beneficial effects of the present invention:

The good emulsifying properties and interface properties of the glycosylated protein-polyphenol nanocomposite of the present invention can effectively inhibit the coalescence phenomenon between oil droplets, so that the emulsion droplets show good uniformity, and the uniformity of the emulsion droplets and the storage stability D. At the same time, the glycosylation reaction enables the protein to form a denser and thicker interfacial layer outside the oil droplets loaded with active substances, which inhibits the interaction between active substances and pro-oxidants (metal ions, free radicals, dissolved oxygen). Moreover, epigallocatechin gallate, as a polyhydroxy phenolic substance, has strong antioxidant capacity (such as free radical scavenging and metal ion chelating capacity), which can effectively scavenge or chelate prooxidants trying to enter the droplets , thereby improving the retention rate of active substances.

Other features and advantages of the present invention will be described in detail in the detailed description that follows.

Description of drawings

Figure 1 shows the particle size distribution diagram of the β-carotene emulsion prepared in Example 1 of the present invention.

FIG. 2 shows a laser confocal image of the β-carotene emulsion prepared in Example 1 of the present invention.

Figure 3 shows the storage stability analysis diagram of the β-carotene emulsion prepared in Example 1 of the present invention.

FIG. 4 shows the salt ion stability analysis diagram of the β-carotene emulsion prepared in Example 1 of the present invention.

Figure 5 shows the thermal stability analysis diagram of the β-carotene emulsion prepared in Example 1 of the present invention.

FIG. 6 shows the stability analysis diagram of the β-carotene emulsion prepared in Example 1 of the present invention.

Detailed ways

Preferred embodiments of the present invention will be described in more detail below. While the preferred embodiments of the present invention are described below, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art.

Example 1

The present embodiment provides a method for preparing a β-carotene uniform emulsion from a whey protein isolate glycosylation reaction product, comprising the following steps:

1) Preparation of whey protein isolate glycosylation reaction product

Mix whey protein isolate with D-(+) lactose and water to obtain a mixed solution of whey protein isolate and D-(+) lactose, adjust the pH of the mixed solution to 7 with sodium hydroxide solution, freeze-dry to obtain protein -lactose mixed powder; the protein-lactose mixed powder was placed in an environment with a humidity of 70% to 79% and a temperature of 68°C for 18 hours to obtain glycosylated whey protein isolate powder;

Among them, the mass ratio of whey protein isolate and D-(+) lactose is 1:1.5, and in the mixed solution of whey protein isolate and D-(+) lactose, the total amount of whey protein isolate and D-(+) lactose 7.5% mass

2) Preparation of glycosylated protein-polyphenol complexes

Mix the glycosylated whey protein isolate powder with deionized water to obtain a 5 mg/mL glycosylated whey protein isolate solution, add epigallocatechin gallate powder, and use a hydrochloric acid solution to adjust the pH of the solution to 3.0-3.3, The glycosylated protein-polyphenol complex is obtained after fully mixing until the mixed solution becomes milky white;

Wherein, the mass ratio of glycosylated whey protein isolate powder to epigallocatechin gallate is 1:1.

3) Preparation of β-carotene homogeneous emulsion

Dissolve β-carotene in medium chain fatty acid glycerides, centrifuge (12000rpm, 10min) to remove insoluble matter to obtain a 0.075% β-carotene solution, and then mix the β-carotene solution with the glycosylated protein in step 2). - The polyphenol complex is mixed and homogenized (10000rpm, 2min), the mass ratio of the β-carotene solution and the glycosylated protein-polyphenol complex is 2:1 to obtain a β-carotene uniform emulsion (the volume fraction of the milk phase is 100%).

In the above-mentioned steps, the method of magnetic stirring is used for mixing, and it is ensured that the substances are fully dissolved.

FIG. 1 shows the particle size distribution diagram of the β-carotene emulsion prepared in Example 1 of the present invention, and FIG. 2 shows the laser confocal image of the β-carotene emulsion prepared in Example 1 of the present invention. It can be seen that the structure and particle size distribution of the β-carotene uniform emulsion prepared by glycosylated whey protein isolate-polyphenol nanocomposite, the protein is uniformly adsorbed on the surface of the emulsion droplets, forming a perfect uniform emulsion structure, and The particle size distribution is uniform and the stability is good.

Figure 3 shows the storage stability analysis diagram of the β-carotene emulsion prepared in Example 1 of the present invention. After loading β-carotene, the initial particle size did not change significantly. With the prolongation of storage time, the particle size of β-carotene loaded in the glycosylated WPI-Lac/EGCG emulsion did not change significantly, and it remained 50 μm after 30 days. , has good storage stability.

FIG. 4 shows the salt ion stability analysis diagram of the β-carotene emulsion prepared in Example 1 of the present invention. Among them, A is the macroscopic schematic diagram of the β-carotene emulsion under different salt ion concentrations, B is the microstructure diagram of the β-carotene emulsion when the salt ion concentration is 0 mM, and C is the β-carotene emulsion microscopic view when the salt ion concentration is 50 mM Structural diagram, D is the microstructure diagram of the β-carotene emulsion when the salt ion concentration is 100mM, E is the microstructure diagram of the β-carotene emulsion when the salt ion concentration is 200mM; it can be seen from Figure B that the embedded β-carotene is The average particle size of the WPI-Lac/EGCG emulsion droplets increased slightly, gradually increasing from the initial 60 μm (measured by machine), and when the salt ion concentration increased to 200 mM (Figure E), the particle size increased by 75 μm (measured by machine). ), but the particle size distribution is still relatively uniform at this time, showing a single peak shape, which indicates that the uniform emulsion stabilized by WPI-Lac/EGCG nanoparticles has good salt resistance.

Figure 5 shows the thermal stability analysis diagram of the β-carotene emulsion prepared in Example 1 of the present invention. Among them, A is the macroscopic schematic diagram of the β-carotene emulsion treated at different temperatures, B is the microstructure of the β-carotene emulsion at room temperature (25°C), and C is the microstructure of the β-carotene emulsion treated at 50°C for 15min Figure, D is the microstructure of the β-carotene emulsion treated at 85 °C for 15 min. It can be seen from Figures B-D that the WPI-Lac/EGCG stabilized emulsion has good thermal stability, strong interfacial adsorption energy, and particle size of the emulsion. The change is small, the particle size of the β-carotene-loaded emulsion is gradually stabilized at about 50 μm (measured by machine), the emulsion droplets are spherical, and the size is uniformly distributed, which is not affected by temperature.

FIG. 6 shows the stability analysis diagram of the β-carotene emulsion prepared in Example 1 of the present invention. The half-life of β-carotene in WPI-Lac/EGCG emulsion reached 175h, and the homogeneous emulsion prepared by glycosylated WPI-Lac/EGCG nanoparticles had a strong protective effect on β-carotene.

Various embodiments of the present invention have been described above, and the foregoing descriptions are exemplary, not exhaustive, and not limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims (10)

1. A method for preparing β -carotene uniform emulsion from whey protein isolate glycosylation reaction products, which is characterized by comprising the following steps:

1) preparation of whey protein isolate glycosylation reaction product

Mixing the whey protein isolate, D- (+) lactose and water to obtain a mixed solution of the whey protein isolate and the D- (+) lactose, adjusting the pH value of the mixed solution to 6.5-7.5, and freeze-drying to obtain protein-lactose mixed powder; placing the protein-lactose mixed powder in an environment with the humidity of 70-79% and the temperature of 65-70 ℃ for reaction to obtain glycosylated whey separated protein powder;

2) preparation of glycosylated protein-polyphenol complexes

Mixing the glycosylated whey protein isolate powder with water to obtain a glycosylated whey protein isolate solution, adding epigallocatechin gallate powder, adjusting the pH of the solution to 3.0-3.3, and fully mixing until the mixed solution turns to milk white to obtain the glycosylated protein-polyphenol compound;

3) β preparation of Carotene homogeneous emulsion

Dissolving β -carotene in an oil phase, centrifuging to remove insoluble substances to obtain β -carotene solution, and mixing and homogenizing the β -carotene solution and the glycosylated protein-polyphenol compound obtained in the step 2) to obtain the β -carotene uniform emulsion.

2. The method according to claim 1, wherein in the step 1), the mass ratio of the whey protein isolate to the D- (+) lactose is 1: 1 to 2.

3. The method according to claim 1, wherein in the mixed solution of whey protein isolate and D- (+) lactose in step 1), the total mass of whey protein isolate and D- (+) lactose is 5-10%.

4. The method according to claim 1, wherein the reaction time in step 1) is 12 to 24 hours.

5. The method according to claim 1, wherein in step 2), the concentration of glycated whey protein isolate in the glycated whey protein isolate solution is 4mg/mL to 6 mg/mL.

6. The method according to claim 1, wherein in the step 2), the mass ratio of the glycosylated whey protein isolate powder to the epigallocatechin gallate is 1-2: 1 to 2.

7. The method according to claim 1, wherein in step 3), the concentration of β -carotene in the β -carotene solution is 0.05% -0.1%.

8. The method according to claim 1, wherein in the step 3), the mass ratio of the β -carotene solution to the glycosylated protein-polyphenol complex is 6-7: 3-4.

9. The method according to claim 1, wherein, in step 3),

the centrifugal rotating speed is 10000 rpm-12000 rpm, and the time is 10 min-15 min;

the homogenizing rotating speed is 7500 rpm-15000 rpm, and the time is 2 min-3 min.

10. A homogeneous emulsion prepared by the process of any one of claims 1 to 9.

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