阅读说明：本技术 一种含有以大豆分离蛋白制备的高密度内水相的水包油包水乳液的制作方法 (Method for preparing water-in-oil-in-water emulsion containing high-density internal water phase prepared from soybean protein isolate ) 是由 李杨 李礼佳 吴长玲 和铭钰 杨浩冬 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种含有以大豆分离蛋白制备的高密度内水相的水包油包水乳液的制作方法,包括以下步骤：(1)大豆分离蛋白提取；(2)大豆分离蛋白高密度内水相制备；(3)水包油包水乳液油相制备；(4)水包油包水乳液外水相制备；(5)水包油包水乳液初乳制备；(6)高压均质；(7)低温保存。本发明以大豆分离蛋白为主要原料,通过将大豆分离蛋白溶于去离子水中制备高密度水包油包水乳液内水相以提高水包油包水乳液的稳定性和理化性能,并对其加工制备条件和配方进行优化,所制备的水包油包水乳液具有优秀的流变学性质、内水相保留率、较小的粒径且稳定性高,工艺简单,生产成本低,能丰富提高水包油包水乳液稳定性的手段,为水包油包水乳液的应用提供一定的理论依据,同时也为大豆副产物的开发和利用提供了一定的参考。(The invention discloses a method for preparing a water-in-oil-in-water emulsion containing a high-density internal water phase prepared from soybean protein isolate, which comprises the following steps: (1) extracting isolated soy protein; (2) preparing a high-density internal water phase of the soybean protein isolate; (3) preparing an oil phase of a water-in-oil-in-water emulsion; (4) preparing an external water phase of a water-in-oil-in-water emulsion; (5) preparing water-in-oil-in-water emulsion primary emulsion; (6) homogenizing under high pressure; (7) and (5) low-temperature preservation. The soybean protein isolate is used as a main raw material, the soybean protein isolate is dissolved in deionized water to prepare the inner water phase of the high-density water-in-oil-in-water emulsion so as to improve the stability and the physical and chemical properties of the water-in-oil-in-water emulsion, and the processing and preparation conditions and the formula of the water-in-oil-in-water emulsion are optimized.)

1. A method for preparing a water-in-oil-in-water emulsion containing a high-density internal aqueous phase prepared from soy protein isolate, comprising the steps of: (1) extracting isolated soy protein; (2) preparing a high-density internal water phase of the soybean protein isolate; (3) preparing an oil phase of a water-in-oil-in-water emulsion; (4) preparing an external water phase of a water-in-oil-in-water emulsion; (5) preparing water-in-oil-in-water emulsion primary emulsion; (6) homogenizing under high pressure of 40MPa for one time; (7) and (5) low-temperature preservation.

2. The method of claim 1, wherein the water-in-oil-in-water emulsion comprising a high-density internal aqueous phase prepared from soy protein isolate comprises: the extraction of the isolated soy protein in the step (1) comprises the following steps: grinding soybeans, degreasing with n-hexane, dissolving the degreased soybean meal in deionized water at a feed-liquid ratio of 1:8, adjusting the pH to 9.0 with sodium hydroxide, continuously stirring the mixture for 2h, centrifuging at 4000r/min for 15min, collecting supernatant, adjusting the pH to 4.5 with hydrochloric acid, centrifuging at 4000r/min for 15min, dispersing precipitated protein in deionized water to eliminate soluble impurities such as inorganic salts, and freeze-drying by a freeze dryer to obtain the soybean protein isolate.

3. The method of claim 1, wherein the water-in-oil-in-water emulsion comprising a high-density internal aqueous phase prepared from soy protein isolate comprises: the preparation of the high-density internal water phase of the soybean protein isolate in the step (2) comprises the following steps: dissolving the soybean protein isolate in deionized water at a feed-liquid ratio of 1:10, and stirring at room temperature for 30 min.

4. The method of claim 1, wherein the water-in-oil-in-water emulsion comprising a high-density internal aqueous phase prepared from soy protein isolate comprises: the oil phase preparation of the water-in-oil-in-water emulsion in the step (3) comprises the following steps: measuring oleum Olivarum, adding polyglycerol ricinoleate with an addition amount of 5%, and stirring for 30 min.

5. The method of claim 1, wherein the water-in-oil-in-water emulsion comprising a high-density internal aqueous phase prepared from soy protein isolate comprises: the preparation of the water-in-oil-in-water emulsion external water phase in the step (4) comprises the following steps: tween 20 is weighed and added into deionized water, the adding amount is 5 percent, and the stirring is carried out for 30 min.

6. The method of claim 1, wherein the water-in-oil-in-water emulsion comprising a high-density internal aqueous phase prepared from soy protein isolate comprises: the preparation of the water-in-oil-in-water emulsion colostrum in the step (5) comprises the following steps: adding the high-density internal water phase of the isolated soy protein into the oil phase in a ratio of 1:4, performing high-speed shearing homogenization for 10min, adding the obtained emulsion into the external water phase in a ratio of 3:7, and performing high-speed shearing homogenization for 10min, wherein the first high-speed shearing homogenization rate is 10000rpm, and the second high-speed shearing homogenization rate is 8000 rpm.

Technical Field

The invention relates to a method for preparing a water-in-oil-in-water emulsion containing a high-density internal water phase prepared from soybean protein isolate, belonging to the technical field of multiple emulsion processing.

Background

By water-in-oil-in-water emulsion is meant an emulsion in which one is dispersed as small droplets in another emulsion system. As one of multiple emulsions, the inner aqueous phase of a water-in-oil-in-water emulsion is dispersed in an oil phase, which is in turn uniformly dispersed in an outer aqueous phase to form a two-film three-phase structure. The structure enables the water-in-oil-in-water emulsion to have wide application prospect in the fields of medical treatment, cosmetics and food. Water-in-oil-in-water emulsions in food products are commonly used in the preparation of low calorie foods, in the entrapment and controlled release of active substances and in the preparation of animal fat substitutes, among others. However, double emulsions are thermodynamically unstable and their destabilization mechanism is often manifested by aggregation of the internal aqueous phase or oil phase, migration of components between the internal and external aqueous phases. The composition and stability of the internal water phase play an important role in the stability of the water-in-oil-in-water emulsion, the load functional component is the main function of the internal water phase of the water-in-oil-in-water emulsion, besides the addition of electrolyte with a certain concentration for balancing the osmotic pressure difference of the internal water phase and the external water phase, food-grade biological macromolecules added in the internal water phase can be used as a thickening agent to improve the emulsion stability and delay the release of embedding substances, and simultaneously the internal water phase can be converted into soft solid particles so as to eliminate the expansion of the internal water phase caused by osmotic pressure gradient.

China is a main country for soybean production and consumption in the world, and with the continuous development of the soybean industry, the development and application of various soybean byproducts are deepened more and more. Among the soybean by-products, the soybean protein isolate has the widest application range and the best performance. The soybean protein isolate is a complete protein food additive produced by using low-temperature desolventized soybean meal as a raw material. The isolated soy protein has a protein content of above 90%, and approximately 20 kinds of amino acids, and contains essential amino acids for human body. It is rich in nutrients, contains no cholesterol, and is one of a few varieties capable of replacing animal proteins in plant proteins. The soybean protein isolate is a surfactant which can reduce both the surface tension of water and oil and the surface tension of water and air, and has excellent emulsifiability. A stable emulsion is easily formed. In the preparation of baked food, frozen food and soup food, the soybean protein isolate is added as an emulsifier to stabilize the state of the product, and the product has higher viscosity, plasticity and elasticity due to the excellent gel property, so that the soybean protein isolate can be used as a carrier of water and can also be used as a carrier of flavoring agent, sugar and other complexes, which is very beneficial to food processing. Therefore, the soybean protein isolate is added into the internal water phase of the water-in-oil-in-water emulsion, so that the gel degree and the stability of the internal water phase can be improved, and the physical and chemical properties of the water-in-oil-in-water emulsion are improved.

The soybean protein isolate is used as a main raw material, the soybean protein isolate is dissolved in deionized water to prepare the inner water phase of the high-density water-in-oil-in-water emulsion so as to improve the stability and the physical and chemical properties of the water-in-oil-in-water emulsion, and the processing and preparation conditions and the formula of the water-in-oil-in-water emulsion are optimized.

Disclosure of Invention

In order to solve the problems of stability and stability of water-in-oil-in-water emulsion and promote application of soy protein isolate in a multiple emulsion system, the invention provides a method for preparing water-in-oil-in-water emulsion containing high-density internal water phase prepared from soy protein isolate, and the technical scheme is as follows:

the method comprises the following steps: extracting isolated soy protein: grinding soybeans, degreasing the ground soybeans with n-hexane, dissolving the degreased soybean meal in deionized water at a feed-liquid ratio of 1:8, adjusting the pH to 9.0 with sodium hydroxide, continuously stirring the mixture for 2 hours, centrifuging the mixture at 4000r/min for 15min, collecting supernatant, adjusting the pH to 4.5 with hydrochloric acid, centrifuging the mixture at 4000r/min for 15min, dispersing precipitated protein in the deionized water to eliminate soluble impurities such as inorganic salt, and freeze-drying the protein by a freeze dryer to obtain soybean protein isolate;

step two: preparing a high-density internal water phase of the soybean protein isolate: dissolving soybean protein isolate in deionized water at a feed-liquid ratio of 1:10, and stirring at room temperature for 30 min;

step three: oil phase preparation of water-in-oil-in-water emulsion: measuring olive oil, adding polyglycerol ricinoleate into olive oil with the addition amount of 5%, and stirring for 30 min;

step four: the preparation method of the external water phase of the water-in-oil-in-water emulsion comprises the following steps: weighing Tween 20, adding into deionized water with the addition amount of 5%, and stirring for 30 min;

step five: preparation of water-in-oil-in-water emulsion colostrum: adding the high-density internal water phase of the isolated soy protein into the oil phase in a ratio of 1:4, performing high-speed shearing homogenization for 10min, adding the obtained emulsion into the external water phase in a ratio of 3:7, and performing high-speed shearing homogenization for 10min, wherein the first high-speed shearing homogenization rate is 10000rpm, and the second high-speed shearing homogenization rate is 8000 rpm;

step six: high-pressure homogenization: homogenizing at 40Mpa for one time;

step seven: storing at low temperature;

the invention has the beneficial effects that:

the method takes the isolated soy protein as a raw material, prepares the water-in-oil-in-water emulsion with high-density internal water phase by dissolving the isolated soy protein in deionized water, optimizes the processing and preparation process conditions and process formula of the water-in-oil-in-water emulsion, has good rheological property, internal water phase retention rate, smaller particle size, high stability, simple process and low production cost, can enrich the means for improving the stability of the water-in-oil-in-water emulsion, provides a certain theoretical basis for the application of the water-in-oil-in-water emulsion, and simultaneously provides a certain reference for the development and utilization of the soybean by-products.

Detailed description of the preferred embodiments

The present invention will be further described with reference to the following specific examples, but the present invention is not limited to these examples. The following examples used the following main raw materials, reagents and experimental equipment:

(1) main raw materials and reagents: selecting soybean, n-hexane, hydrochloric acid, sodium hydroxide, olive oil, sodium chloride, polyglycerol ricinoleate, tween-20 and deionized water;

(2) experimental equipment: a water bath, a centrifuge, a freeze dryer, a high-pressure homogenizer, an electronic analytical balance, a pH meter, a high-speed stirrer and a high-speed shearing homogenizer.

Example 1:

the embodiment provides a method for preparing a water-in-oil-in-water emulsion containing a high-density internal water phase prepared from isolated soy protein, which comprises the following specific steps:

the method comprises the following steps: extracting isolated soy protein: grinding soybeans, degreasing the ground soybeans with n-hexane, dissolving the degreased soybean meal in deionized water at a feed-liquid ratio of 1:8, adjusting the pH to 9.0 with sodium hydroxide, continuously stirring the mixture for 2 hours, centrifuging the mixture at 4000r/min for 15min, collecting supernatant, adjusting the pH to 4.5 with hydrochloric acid, centrifuging the mixture at 4000r/min for 15min, dispersing precipitated protein in the deionized water to eliminate soluble impurities such as inorganic salt, and freeze-drying the protein by a freeze dryer to obtain soybean protein isolate;

step two: preparing a high-density internal water phase of the soybean protein isolate: dissolving soybean protein isolate in deionized water at a feed-liquid ratio of 1:10, and stirring at room temperature for 30 min;

step three: oil phase preparation of water-in-oil-in-water emulsion: measuring olive oil, adding polyglycerol ricinoleate into olive oil with the addition amount of 5%, and stirring for 30 min;

step four: the preparation method of the external water phase of the water-in-oil-in-water emulsion comprises the following steps: weighing Tween 20, adding into deionized water with the addition amount of 5%, and stirring for 30 min;

step five: preparation of water-in-oil-in-water emulsion colostrum: adding the high-density internal water phase of the isolated soy protein into the oil phase in a ratio of 1:4, performing high-speed shearing homogenization for 10min, adding the obtained emulsion into the external water phase in a ratio of 3:7, and performing high-speed shearing homogenization for 10min, wherein the first high-speed shearing homogenization rate is 10000rpm, and the second high-speed shearing homogenization rate is 8000 rpm;

step six: high-pressure homogenization: homogenizing at 40Mpa for one time;

step seven: storing at low temperature;

example 2:

the embodiment provides a method for preparing a water-in-oil-in-water emulsion without adding soy protein isolate in an internal water phase, which comprises the following specific steps:

the method comprises the following steps: preparation of water phase in water-in-oil-in-water emulsion: weighing sodium chloride, and dissolving the sodium chloride in deionized water, wherein the addition amount of the sodium chloride is 0.5%;

step two: oil phase preparation of water-in-oil-in-water emulsion: measuring olive oil, adding polyglycerol ricinoleate into olive oil with the addition amount of 5%, and stirring for 30 min;

step three: the preparation method of the external water phase of the water-in-oil-in-water emulsion comprises the following steps: weighing Tween 20, adding into deionized water with the addition amount of 5%, and stirring for 30 min;

step four: preparation of water-in-oil-in-water emulsion colostrum: adding the inner water phase into the oil phase at a ratio of 1:4, performing high-speed shearing homogenization for 10min, adding the obtained emulsion into the outer water phase at a ratio of 3:7, and performing high-speed shearing homogenization for 10min, wherein the first high-speed shearing homogenization rate is 10000rpm, and the second high-speed shearing homogenization rate is 8000 rpm;

step five: high-pressure homogenization: homogenizing at 40Mpa for one time;

step six: storing at low temperature;

example 3:

the embodiment provides a method for preparing a water-in-oil-in-water emulsion which contains a high-density internal water phase prepared from isolated soy protein and does not add an emulsifier to an external water phase, and the method comprises the following specific steps:

the method comprises the following steps: extracting isolated soy protein: grinding soybeans, degreasing the ground soybeans with n-hexane, dissolving the degreased soybean meal in deionized water at a feed-liquid ratio of 1:8, adjusting the pH to 9.0 with sodium hydroxide, continuously stirring the mixture for 2 hours, centrifuging the mixture at 4000r/min for 15min, collecting supernatant, adjusting the pH to 4.5 with hydrochloric acid, centrifuging the mixture at 4000r/min for 15min, dispersing precipitated protein in the deionized water to eliminate soluble impurities such as inorganic salt, and freeze-drying the protein by a freeze dryer to obtain soybean protein isolate;

step two: preparing a high-density internal water phase of the soybean protein isolate: dissolving soybean protein isolate in deionized water at a feed-liquid ratio of 1:10, and stirring at room temperature for 30 min;

step three: oil phase preparation of water-in-oil-in-water emulsion: measuring olive oil, adding polyglycerol ricinoleate into olive oil with the addition amount of 5%, and stirring for 30 min;

step four: preparation of water-in-oil-in-water emulsion colostrum: adding the high-density internal water phase of the isolated soy protein into an oil phase in a ratio of 1:4, performing high-speed shearing homogenization for 10min, adding the obtained emulsion into deionized water in a ratio of 3:7, and performing high-speed shearing homogenization for 10min, wherein the first high-speed shearing homogenization rate is 10000rpm, and the second high-speed shearing homogenization rate is 8000 rpm;

step five: high-pressure homogenization: homogenizing at 40Mpa for one time;

step six: storing at low temperature;

example 4:

the embodiment provides a method for preparing a water-in-oil-in-water emulsion with an internal water phase without adding soy protein isolate and an external water phase without adding an emulsifier, which comprises the following specific steps;

the method comprises the following steps: preparation of water phase in water-in-oil-in-water emulsion: weighing sodium chloride, and dissolving the sodium chloride in deionized water, wherein the addition amount of the sodium chloride is 0.5%;

step two: oil phase preparation of water-in-oil-in-water emulsion: measuring olive oil, adding polyglycerol ricinoleate into olive oil with the addition amount of 5%, and stirring for 30 min;

step four: preparation of water-in-oil-in-water emulsion colostrum: adding the internal water phase into the oil phase at a ratio of 1:4, performing high-speed shearing homogenization for 10min, adding the obtained emulsion into deionized water at a ratio of 3:7, and performing high-speed shearing homogenization for 10min, wherein the first high-speed shearing homogenization rate is 10000rpm, and the second high-speed shearing homogenization rate is 8000 rpm;

step five: high-pressure homogenization: homogenizing at 40Mpa for one time;

step six: storing at low temperature;

the following is a portion of the experimental data:

TABLE 1 comparison of the effects of the examples

Experimental group	Example 1	Example 2	Example 3	Example 4
					Internal aqueous phase Retention (%)	95.12	58.17	88.31	54.26
Particle size (nm)	634	1272	963	2866
					Viscosity (Pa s)	8.28	6.33	7.48	4.46
Storage modulus (Pa)	31.88	3.21	26.46	3.35
					Stability (%)	88.67	50.81	81.73	43.58

As shown in the table, according to comparison of specific examples 1 to 4, it is found that the water-in-oil-in-water emulsion containing the high-density internal water phase prepared from the soy protein isolate has the best physicochemical indexes, and the retention rate, particle size, viscosity, storage modulus and stability of the internal water phase are the best, respectively: 95.12 percent, 634nm, 8.28Pa, 31.88 Pa.s and 88.67 percent, but the physical and chemical indexes of the water-in-oil-in-water emulsion which does not contain the high-density internal water phase prepared by the soybean protein isolate are poor; in addition, the physical and chemical indexes of comparative examples 1 to 4 show that the isolated soy protein can generate a synergistic effect with the traditional hydrophilic emulsifier, the stability of the double-layer emulsion is obviously improved under the condition that the inner water phase contains the isolated soy protein and the outer water phase contains Tween 20, and the physical and chemical indexes are excellent.

In conclusion, the soybean protein isolate is used as a raw material, the soybean protein isolate is dissolved in deionized water to prepare the water-in-oil-in-water emulsion with the high-density internal water phase, and the processing and preparation process conditions and the process formula are optimized, so that the prepared water-in-oil-in-water emulsion has good rheological property, internal water phase retention rate, smaller particle size and high stability, the process is simple, the production cost is low, the means for improving the stability of the water-in-oil-in-water emulsion can be enriched, a certain theoretical basis is provided for the application of the water-in-oil-in-water emulsion, and a certain reference is provided for the development and utilization of soybean byproducts.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.