阅读说明：本技术 一种纳米级油凝胶及其制备方法 (Nano-scale oil gel and preparation method thereof ) 是由 殷丽君 贾鑫 张明皓 闫文佳 颜金鑫 栾怡雪 于 2021-09-15 设计创作，主要内容包括：本发明提供了一种纳米级油凝胶的制备方法,包括：A)葵花籽油和凝胶剂加热混合搅拌,冷却得到油相；B)将预处理后的乳清蛋白和油相混合,得到混合液；混合液与乳化剂剪切混合,加热后冷却,得到冷却后混合液；C)冷却后混合液与木瓜蛋白酶混合水解,离心分离得到油凝胶。本发明采用了一种水相与油相共凝胶的乳液凝胶法制备出一种新型的纳米级油凝胶,即通过热诱导方式使水相(乳清蛋白溶液)和油相(葵花籽油)均诱导成胶,然后用蛋白酶水解外层乳清蛋白凝胶水相外壳,离心得到纳米级小粒径油凝胶。本发明原辅料均为食品级可应用于食品加工；加工工艺可以将纳米级油凝胶单独分离出来,便于储藏、加工和运输。(The invention provides a preparation method of nanoscale oil gel, which comprises the following steps: A) heating, mixing and stirring the sunflower seed oil and the gel, and cooling to obtain an oil phase; B) mixing the pretreated whey protein with an oil phase to obtain a mixed solution; shearing and mixing the mixed solution and an emulsifier, heating and cooling to obtain a cooled mixed solution; C) cooling, mixing the mixed solution with papain, hydrolyzing, and centrifuging to obtain oleogel. The invention adopts an emulsion-gel method of cogelling a water phase and an oil phase to prepare a novel nano-scale oleogel, namely, the water phase (whey protein solution) and the oil phase (sunflower seed oil) are both induced to form gel in a thermal induction mode, then the outer layer whey protein gel water phase shell is hydrolyzed by protease, and the nano-scale small-particle-size oleogel is obtained by centrifugation. The raw materials and auxiliary materials are all food-grade materials which can be applied to food processing; the processing technology can separate the nanometer oil gel independently, and is convenient for storage, processing and transportation.)

1. A method for preparing a nanoscale oil gel, comprising:

A) mixing sunflower seed oil and gel under stirring to obtain oil phase;

B) mixing the pretreated whey protein with an oil phase to obtain a mixed solution; shearing and mixing the mixed solution and an emulsifier, heating and cooling to obtain a cooled mixed solution;

C) cooling, mixing the mixed solution with papain, hydrolyzing, centrifuging to obtain oil phase, and distilling to obtain oleogel.

2. The method of claim 1, wherein the gelling agent of step a) comprises γ -oryzanol and β -sitosterol; the mass ratio of the gamma-oryzanol to the beta-sitosterol is 3: 7-7: 3; the gel accounts for 5-9% of the total mass of the oil phase.

3. The preparation method according to claim 1, wherein the stirring in step A) is heating stirring at 80-90 ℃; cooling to 20-30 ℃ after stirring;

the emulsifier in the step B) is Tween-20; the emulsifier accounts for 1-2% of the mixed solution by mass.

4. The method for preparing according to claim 1, characterized in that the pretreated whey protein is in particular:

stirring the whey protein solution, and standing at 4 ℃; the concentration of the whey protein is 4-12 wt%; the stirring time is 2-3 h; the stirring temperature is 20-30 ℃; the standing time is 16-24 h.

5. The preparation method according to claim 1, wherein the oil phase in step B) accounts for 5 to 12.5 mass percent of the mixed solution.

6. The method according to claim 1, wherein the shear mixing of step B) is in particular: shearing and mixing at 10000-11000 rpm for 1-1.5 min.

7. The method according to claim 1, wherein the heating temperature in step B) is 85 to 95 ℃; the time is 25-35 min; the cooling is 2-8 ℃.

8. The method according to claim 1, wherein the concentration of papain in step C) is: 2 ten thousand U/g mixed solution; the hydrolysis temperature is 20-30 ℃; the hydrolysis time is 10-12 h; the centrifugation is specifically 7000rpm centrifugation for 10 min.

9. A nanoscale oil gel characterized by being prepared by the preparation method of any one of claims 1 to 9.

10. A product comprising the nano-sized oil gel prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of food, in particular to a nanoscale oleogel and a preparation method thereof.

Background

Oleogels (oleogels or edible organogels), generally referred to as food grade organogels, are a mixture of solids-like lipids with certain viscosity and elasticity, typically composed of edible vegetable oils and food grade gelators.

When the oil phase is captured by the gelling agent, a network structure is formed, and the gel network limits the movement of the grease through different acting forces such as hydrogen bonds, van der waals force, electrostatic force and the like. The structured oil system has the advantages of no trans fatty acid or low saturated fatty acid and high unsaturated fatty acid, meets the requirements of people on healthy diet, and has great application potential. Gelators are a key component in oleogels, and their structure directly affects the properties of oleogels.

At present, common oil gel systems are mostly seen in macroscopic size gel, research on nano-scale oil gel is less, and research on emulsion preparation is mostly concentrated, and the oil gel prepared by the method not only has larger particle size, but also is a micro-unstable system of emulsion, and is not beneficial to transportation, processing and application.

Therefore, it is necessary to prepare an oleogel that can be separated from the emulsion and exists alone as an oleogel, which facilitates storage and transportation.

Disclosure of Invention

In view of the above, the nano-sized oil gel provided by the invention can be separated from the emulsion independently, and has a nano-scale size.

The invention provides a preparation method of nanoscale oil gel, which comprises the following steps:

A) heating, mixing and stirring the sunflower seed oil and the gel, and cooling to obtain an oil phase;

B) mixing the pretreated whey protein with an oil phase to obtain a mixed solution; shearing and mixing the mixed solution and an emulsifier, heating and cooling to obtain a cooled mixed solution;

C) cooling, mixing the mixed solution with papain, hydrolyzing, and centrifuging to obtain oleogel.

Preferably, the gelling agent in the step A) comprises gamma-oryzanol and beta-sitosterol; the mass ratio of the gamma-oryzanol to the beta-sitosterol is 3: 7-7: 3; the gel accounts for 5-9% of the total mass of the oil phase.

Preferably, the stirring in the step A) is heating and stirring at 85-95 ℃; cooling to 20-30 ℃ after stirring;

the emulsifier in the step B) is Tween-20; the emulsifier accounts for 1-2% of the mixed solution by mass.

Preferably, the pretreated whey protein is specifically:

stirring the whey protein solution, and standing at 4 ℃; the concentration of the whey protein is 4-12 wt%; the stirring time is 2-3 h; the stirring temperature is 20-30 ℃; the standing time is 16-24 h.

Preferably, the oil phase in the step B) accounts for 5 to 12.5 mass percent of the mixed solution.

Preferably, the shear mixing in the step B) is specifically: shearing and mixing at 10000-11000 rpm for 1-1.5 min.

Preferably, the heating temperature in the step B) is 85-95 ℃; the time is 25-35 min; the cooling is 2-8 ℃.

Preferably, the concentration of the papain in the step C) is as follows: 2 ten thousand U/g mixed solution; the hydrolysis temperature is 20-30 ℃; the hydrolysis time is 10-12 h; the centrifugation is specifically 7000rpm centrifugation for 10 min.

The invention provides a nanoscale oil gel which is prepared by the preparation method of any one of the technical schemes.

The invention provides a product, which comprises the nanoscale oil gel prepared by the preparation method in any one of the technical schemes.

Compared with the prior art, the invention provides a preparation method of nanoscale oil gel, which comprises the following steps: A) heating, mixing and stirring the sunflower seed oil and the gel, and cooling to obtain an oil phase; B) mixing the pretreated whey protein with an oil phase to obtain a mixed solution; shearing and mixing the mixed solution and an emulsifier, heating and cooling to obtain a cooled mixed solution; C) cooling, mixing the mixed solution with papain, hydrolyzing, and centrifuging to obtain oleogel. The invention adopts an emulsion-gel method of cogelling a water phase and an oil phase to prepare a novel nano-scale oleogel, namely, the water phase (whey protein solution) and the oil phase (sunflower seed oil) are both induced to form gel in a thermal induction mode, then the outer layer whey protein gel water phase shell is hydrolyzed by protease, and the nano-scale small-particle-size oleogel is obtained by centrifugation. The raw materials and auxiliary materials are all food-grade materials which can be applied to food processing; the processing technology can separate the nanometer oil gel independently, and is convenient for storage, processing and transportation.

Detailed Description

The invention provides a nano-sized oil gel and a preparation method thereof, and a person skilled in the art can appropriately improve process parameters by referring to the content. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope of the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

The invention provides a preparation method of nanoscale oil gel, which comprises the following steps:

A) heating, mixing and stirring the sunflower seed oil and the gel, and cooling to obtain an oil phase;

B) mixing the pretreated whey protein with an oil phase to obtain a mixed solution; shearing and mixing the mixed solution and an emulsifier, heating and cooling to obtain a cooled mixed solution;

C) cooling, mixing the mixed solution with papain, hydrolyzing, and centrifuging to obtain oleogel.

The preparation method of the nanometer oleogel provided by the invention firstly mixes and stirs the sunflower seed oil and the oleogel to obtain the oil phase.

The raw material of the invention is sunflower seed oil with high content of unsaturated fatty acid, and the effect is better compared with the soybean oil in the prior art.

The gel comprises gamma-oryzanol and beta-sitosterol; the mass ratio of the gamma-oryzanol to the beta-sitosterol is 3: 7-7: 3, including but not limited to 3:7, 4:6, 5:5, 6:4 and 7: 3.

The gel accounts for 5 to 9 percent of the total mass of the oil phase; including but not limited to 5%, 6%, 7%, 8%, 9%; but also a point value between any of the two.

The gamma-oryzanol and the beta-sitosterol can be used as the gel of the oil gel after being mixed according to the proportion, and the gamma-oryzanol and the beta-sitosterol can form a fibrous structure in a space through the mutual cross-linking of intermolecular hydrogen bond action, thereby having the effects of fixing base oil and fat and constructing the gel. During the cooling process after heating with the base oil, the gamma-oryzanol and the beta-sitosterol do not form gel immediately and need to stand for a period of time to form. The invention has good effect by the matching of the gamma-oryzanol and the beta-sitosterol in the specific proportion.

The stirring is heating stirring at 85-95 ℃; cooling to 20-30 ℃ after stirring;

and mixing the pretreated whey protein with the oil phase to obtain a mixed solution.

The pretreated whey protein of the invention is preferably specifically:

stirring the whey protein solution, and standing at 4 ℃ for later use.

The concentration of the whey protein is preferably 4-12 wt%; more preferably 8-12 wt%; including but not limited to 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%; but also a point value between any of the two.

Whey protein is a by-product of cheese production, has a high nutritional value and good functional properties, and consists mainly of beta-lactoglobulin (beta-lg, about 55%) and alpha-lactalbumin (alpha-la, about 20%). The denaturation temperature of beta-lg is 71.9 ℃, and the denaturation temperature of alpha-la is 64.3 ℃. Thus, for whey protein gels made by heating, the heating temperature is typically above 70 ℃. Whey protein is easily dissolved in water, and is denatured and aggregated after being heated to form a network structure, and the property is called as the gel property of whey protein.

The stirring time is 2-3 h; the stirring temperature is 20-30 ℃; the standing time is 16-24 h.

Mixing the pretreated whey protein with an oil phase, wherein the oil phase accounts for 5-12.5% of the mixed solution by mass; more preferably 5% to 10%; including but not limited to 5%, 7.5%, 10%, 12.5%; but also a point value between any of the two.

Shearing and mixing the mixed solution and the emulsifier.

The emulsifier of the present invention includes, but is not limited to tween-20. The emulsifier accounts for 1-2% of the mixed solution by mass preferably; more preferably 1%.

The shearing and mixing of the invention are preferably as follows: shearing and mixing at 10000-11000 rpm for 1-1.5 min; more preferably, shear mixing is carried out at 11000rpm for 1 min.

And heating the mixed solution and cooling to obtain a cooled mixed solution. The heating temperature is 85-95 ℃; the time is 25-35 min; the cooling is carried out at the temperature of 2-8 ℃; preferably, it is cooled overnight.

Cooling, mixing the mixed solution with papain, and hydrolyzing.

The concentration of the papain is as follows: 2 ten thousand U/g mixed solution;

the hydrolysis temperature is preferably 20-30 ℃; the hydrolysis time is preferably 10-12 h; more preferably 11 to 12 hours.

Hydrolyzing, centrifuging to obtain oil phase, and distilling to obtain oleogel.

The centrifugal separation is specifically 7000rpm centrifugation for 10 min; separating the water phase and the oil phase, taking the white substance on the upper layer, and washing with distilled water for 2-3 times to obtain the oil gel particles.

The whey protein is gelled in the heating process, and the oil phase is gelled after being heated and then cooled, so that the whey protein is firstly gelled in the heating process, the crosslinking range of gelling of the oil gel is limited, the obtained particle size is smaller, the water phase is finally removed, only the nanometer oil gel is reserved, and the influence of the water phase is not required to be considered in both transportation and application.

The invention provides a nanoscale oil gel which is prepared by the preparation method of any one of the technical schemes.

On the basis of preparing the oil gel by the existing emulsion method, the nanometer oil gel is prepared by utilizing the time difference of gel formation by thermal induction of a water phase and an oil phase, and compared with the macroscopic oil gel, the nanometer oil gel has the double advantages of the oil gel and the nanometer particles; and the water phase is removed, and the oil phase is separated out, so that the influence of the water phase and an emulsion system on a final product is eliminated.

Meanwhile, all the raw materials of the invention are food grade, so that the final product is food grade and edible.

The invention provides a product, which comprises the nanoscale oil gel prepared by the preparation method in any one of the technical schemes.

The invention provides a preparation method of nanoscale oil gel, which comprises the following steps: A) heating, mixing and stirring the sunflower seed oil and the gel, and cooling to obtain an oil phase; B) mixing the pretreated whey protein with an oil phase to obtain a mixed solution; shearing and mixing the mixed solution and an emulsifier, heating and cooling to obtain a cooled mixed solution; C) cooling, mixing the mixed solution with papain, hydrolyzing, and centrifuging to obtain oleogel. The invention adopts an emulsion-gel method of cogelling a water phase and an oil phase to prepare a novel nano-scale oleogel, namely, the water phase (whey protein solution) and the oil phase (sunflower seed oil) are both induced to form gel in a thermal induction mode, then the outer layer whey protein gel water phase shell is hydrolyzed by protease, and the nano-scale small-particle-size oleogel is obtained by centrifugation. The raw materials and auxiliary materials are all food-grade materials which can be applied to food processing; the processing technology can separate the nanometer oil gel independently, and is convenient for storage, processing and transportation.

In order to further illustrate the present invention, the following will describe a nanoscale oil gel and a preparation method thereof in detail with reference to examples.

Example 1

Preparation of nanoscale oil gel (1000nm)

Preparing 8% of whey protein solution by mass fraction, stirring for 2 hours at normal temperature, and standing overnight at 4 ℃ for later use.

Weighing the following components in a mass ratio of 6:4, adding 5 percent of gamma-oryzanol and beta-sitosterol into the sunflower seed oil, heating and stirring at 90 ℃ until dissolving to prepare an oil phase, and then cooling to normal temperature for later use. Mixing oil phase and water phase with a total mass of 20.0g, wherein the mass fraction of the oil phase is 5%, adding emulsifier (Tween-20) with a mass fraction of 1.0%, shearing and mixing at 11000rpm for 1min, heating the mixed solution to 90 deg.C, keeping the temperature for 30min, and standing at 4 deg.C for cooling overnight. Taking 15-2% of the cooled mixed solution, adding papain to enable the final concentration of the papain to be 2 ten thousand U/g of emulsion, uniformly mixing, hydrolyzing at normal temperature for 12h, centrifuging at 7000rpm for 10min to separate a water phase and an oil phase, taking a white substance on the upper layer, washing with distilled water twice to obtain oil gel particles, and determining the particle size.

Example 2

Preparation of nanoscale oil gel (900nm)

Preparing 12% of whey protein solution by mass fraction, stirring for 2 hours at normal temperature, and standing overnight at 4 ℃ for later use.

Weighing the following components in a mass ratio of 5:5, adding 5% of gamma-oryzanol and beta-sitosterol into the sunflower seed oil in a total mass fraction, heating and stirring at 90 ℃ until dissolving to prepare an oil phase, and then cooling to normal temperature for later use. Mixing oil phase and water phase with a total mass of 20.0g, wherein the mass fraction of the oil phase is 7.5%, adding emulsifier (Tween-20) with a mass fraction of 1.0%, shearing and mixing at a rotating speed of 11000rpm for 1min, heating the mixed solution to 90 ℃, preserving heat for 30min, and then standing at 4 ℃ for cooling overnight.

And taking the cooled mixed solution, adding papain to enable the final concentration of the papain to be 2 ten thousand U/g emulsion, uniformly mixing, hydrolyzing at normal temperature for 12h, centrifuging at 7000rpm for 10min to separate a water phase and an oil phase, taking the upper white substance, washing with distilled water twice to obtain oil gel particles, and determining the particle size.

Example 3

Preparation of nanoscale oil gel (650nm)

Preparing a whey protein solution with the mass fraction of 6%, stirring for 2 hours at normal temperature, and standing overnight at 4 ℃ for later use.

Weighing the following components in a mass ratio of 6:4, adding 7 percent of gamma-oryzanol and beta-sitosterol into the sunflower seed oil, heating and stirring at 90 ℃ until dissolving to prepare an oil phase, and then cooling to normal temperature for later use. Mixing oil phase and water phase with a total mass of 20.0g, wherein the mass fraction of the oil phase is 7.5%, adding emulsifier (Tween-20) with a mass fraction of 1.0%, shearing and mixing at a rotating speed of 11000rpm for 1min, heating the mixed solution to 90 ℃, preserving heat for 30min, and then standing at 4 ℃ for cooling overnight.

And taking the cooled mixed solution, adding papain to enable the final concentration of the papain to be 2 ten thousand U/g emulsion, uniformly mixing, hydrolyzing at normal temperature for 12h, centrifuging at 7000rpm for 10min to separate a water phase and an oil phase, taking the upper white substance, washing with distilled water twice to obtain oil gel particles, and determining the particle size.

Example 4

Preparation of nanoscale oil gel (600nm)

Preparing 8% of whey protein solution by mass fraction, stirring for 2 hours at normal temperature, and standing overnight at 4 ℃ for later use.

Weighing the following components in a mass ratio of 6:4, adding 6 percent of gamma-oryzanol and beta-sitosterol into the sunflower seed oil, heating and stirring at 90 ℃ until dissolving to prepare an oil phase, and then cooling to normal temperature for later use. Mixing oil phase and water phase with a total mass of 20.0g, wherein the mass fraction of the oil phase is 7.5%, adding emulsifier (Tween-20) with a mass fraction of 1.0%, shearing and mixing at a rotating speed of 11000rpm for 1min, heating the mixed solution to 90 ℃, preserving heat for 30min, and then standing at 4 ℃ for cooling overnight.

And taking the cooled mixed solution, adding papain to enable the final concentration of the papain to be 2 ten thousand U/g emulsion, uniformly mixing, hydrolyzing at normal temperature for 12h, centrifuging at 7000rpm for 10min to separate a water phase and an oil phase, taking the upper white substance, washing with distilled water twice to obtain oil gel particles, and determining the particle size.

Example 5

Preparation of nanoscale oil gel (550nm)

Preparing 12% of whey protein solution by mass fraction, stirring for 2 hours at normal temperature, and standing overnight at 4 ℃ for later use.

Weighing the following components in a mass ratio of 4:6, adding 7 percent of gamma-oryzanol and beta-sitosterol into the sunflower seed oil, heating and stirring at 90 ℃ until dissolving to prepare an oil phase, and then cooling to normal temperature for later use. Mixing oil phase and water phase with a total mass of 20.0g, wherein the mass fraction of the oil phase is 5%, adding emulsifier (Tween-20) with a mass fraction of 1.0%, shearing and mixing at 11000rpm for 1min, heating the mixed solution to 90 deg.C, keeping the temperature for 30min, and standing at 4 deg.C for cooling overnight.

And taking the cooled mixed solution, adding papain to enable the final concentration of the papain to be 2 ten thousand U/g emulsion, uniformly mixing, hydrolyzing at normal temperature for 12h, centrifuging at 7000rpm for 10min to separate a water phase and an oil phase, taking the upper white substance, washing with distilled water twice to obtain oil gel particles, and determining the particle size.

Test example 1 measurement of particle size of nano-sized oil gel by different preparation processes

The particle size of the nanoscale oil gels obtained in examples 1 to 5 was measured, and the results are shown in table 1:

TABLE 1

	Particle size/nm
		Example 1(1000nm)	1032.00±12.00
Example 2(900nm)	919.77±56.28
		Example 3(650nm)	650.77±20.27
Example 4(600nm)	607.57±73.26
		Example 5(550nm)	534.93±16.92

Example 6

Investigating the influence of different oil phase mass fractions on the nanometer oil gel particle size, fixing the total mass fraction of the gel to be 6%, wherein the mass ratio of the gamma-oryzanol to the beta-sitosterol is 6:4 and 6% whey protein concentration, and the other process parameters were carried out according to the methods of examples 1 to 5, and the results are shown in table 2.

TABLE 2

Oil phase mass fraction/%	Particle size/nm
		5.0	2051.33±513.03
7.5	672.30±21.06
		10.0.	2690.33±372.28
12.5	4328.67±405.88

Example 7

The influence of the total mass fraction of different gelling agents on the particle size of the nano-grade oil gel is inspected, the mass fraction of the fixed oil phase is 7.5 percent, and the mass ratio of the gamma-oryzanol to the beta-sitosterol is 6:4 and 6% whey protein concentration, the other process parameters were carried out according to the methods of examples 1 to 5, and the results are shown in table 3.

TABLE 3

Total mass fraction/% of gelling agent	Particle size/nm
		5	1046.00±9.90
6	672.30±21.06
		7	650.77±20.27
8	1256.00±94.14
		9	1498.00±52.33

Example 8

The influence of different mass ratios of gamma-oryzanol and beta-sitosterol on the particle size of the nano-grade oleogel is examined, the mass fraction of the fixed oil phase is 7.5%, the total mass fraction of the gel is 6%, the concentration of the whey protein is 6%, and other step parameters are carried out according to the methods of the examples 1-5, and the results are shown in table 4.

TABLE 4

Mass ratio of oryzanol to sitosterol	Particle size/nm
		7:3	2147.00±156.89
6:4	672.30±21.06
		5:5	1189.00±6.56
4:6	1023.17±57.39
		3:7	2482.33±101.91

Example 9

Investigating the influence of different whey protein concentrations on the particle size of the nano-grade oleogel, wherein the fixed oil phase mass fraction is 7.5%, the total mass fraction of the gel is 6%, and the mass ratio of the gamma-oryzanol to the beta-sitosterol is 6:4, the other step parameters were carried out according to the methods of examples 1 to 5, and the results are shown in Table 5.

TABLE 5

Whey protein concentration/%)	Particle size/nm
		4	1373.00±105.13
6	672.30±21.06
		8	607.57±73.26
10	898.40±47.05
		12	872.63±64.88

Example 10

Selecting four influencing factors of an oil phase mass fraction A, a total mass fraction B of the gel, a mass ratio C of gamma-oryzanol to beta-sitosterol and a whey protein concentration D, carrying out an L9(34) orthogonal test according to the orthogonal test factors and a horizontal table in the table 7, referring to the parameters of the other steps in examples 1-5, and finding the results in tables 6-7.

TABLE 6

TABLE 7

The results of orthogonal experiments show that the influence of all factors on the particle size of the prepared oleogel microspheres is that the primary and secondary sequences are whey protein concentration and gelling agent from large to smallThe total mass fraction, the oil phase mass fraction and the gel mass ratio, and the experimental result shows that the optimal factor level combination is A₁B₃C₂D₃Namely, the oil phase accounts for 5.0 percent by mass, the gel factor accounts for 7 percent by mass, the oryzanol/sitosterol accounts for 5:5 percent by mass, and the whey protein concentration is 12 percent, and the particle size obtained by carrying out the verification experiment of the horizontal combination is 481.80 +/-23.00 nm, which also confirms the result.

Comparative example 1

Preparing a whey protein solution with the mass fraction of 2%, stirring for 2 hours at normal temperature, and standing overnight at 4 ℃ for later use.

Weighing the following components in a mass ratio of 6:4, adding 6 percent of gamma-oryzanol and beta-sitosterol into the sunflower seed oil, heating and stirring at 90 ℃ until dissolving to prepare an oil phase, and then cooling to normal temperature for later use. Mixing oil phase and water phase with a total mass of 20.0g, wherein the mass fraction of the oil phase is 7.5%, adding emulsifier (Tween-20) with a mass fraction of 1.0%, shearing and mixing at a rotating speed of 11000rpm for 1min, heating the mixed solution to 90 ℃, preserving heat for 30min, and then standing at 4 ℃ for cooling overnight.

And taking the cooled mixed solution, adding papain to enable the final concentration of the papain to be 2 ten thousand U/g emulsion, uniformly mixing, hydrolyzing at normal temperature for 12h, centrifuging at 7000rpm for 10min to separate a water phase and an oil phase, taking the upper white substance, washing with distilled water twice to obtain oil gel particles, and determining the particle size. The particle size is measured to be 25675.00 +/-1935.00 nm and is over-large

Comparative example 2

Preparing a whey protein solution with the mass fraction of 6%, stirring for 2 hours at normal temperature, and standing overnight at 4 ℃ for later use.

Weighing the following components in a mass ratio of 6:4, adding 6 percent of gamma-oryzanol and beta-sitosterol into the sunflower seed oil, heating and stirring at 90 ℃ until dissolving to prepare an oil phase, and then cooling to normal temperature for later use. Mixing oil phase and water phase with a total mass of 20.0g, wherein the mass fraction of the oil phase is 2.5%, adding emulsifier (Tween-20) with a mass fraction of 1.0%, shearing and mixing at 11000rpm for 1min, heating the mixed solution to 90 deg.C, keeping the temperature for 30min, and then standing at 4 deg.C for cooling overnight.

And taking the cooled mixed solution, adding papain to enable the final concentration of the papain to be 2 ten thousand U/g emulsion, uniformly mixing, hydrolyzing at normal temperature for 12h, centrifuging at 7000rpm for 10min to separate a water phase and an oil phase, taking the upper white substance, washing with distilled water twice to obtain oil gel particles, and determining the particle size. The particle size was found to be 7421.50. + -. 307.59nm, too large.

Comparative example 3

Preparing a whey protein solution with the mass fraction of 6%, stirring for 2 hours at normal temperature, and standing overnight at 4 ℃ for later use.

Weighing the following components in a mass ratio of 6:4, adding 6 percent of gamma-oryzanol and beta-sitosterol into the sunflower seed oil, heating and stirring at 90 ℃ until dissolving to prepare an oil phase, and then cooling to normal temperature for later use. Mixing oil phase and water phase with a total mass of 20.0g, wherein the mass fraction of the oil phase is 15%, adding emulsifier (Tween-20) with a mass fraction of 1.0%, shearing and mixing at 11000rpm for 1min, heating the mixed solution to 90 ℃, preserving heat for 30min, and then standing at 4 ℃ for cooling overnight.

And taking the cooled mixed solution, adding papain to enable the final concentration of the papain to be 2 ten thousand U/g emulsion, uniformly mixing, hydrolyzing at normal temperature for 12h, centrifuging at 7000rpm for 10min to separate a water phase and an oil phase, taking the upper white substance, washing with distilled water twice to obtain oil gel particles, and determining the particle size. The particle size was found to be 8083.00. + -. 1337.85nm, too large.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.