阅读说明：本技术 一种大豆分离蛋白和金针菇多糖自组装的食用凝胶及其制备方法和应用 (Self-assembled edible gel of soybean protein isolate and flammulina velutipes polysaccharide and preparation method and application thereof ) 是由 胡秋辉 张军淼 马宁 裴斐 马高兴 仲磊 苏安祥 于 2019-09-05 设计创作，主要内容包括：本发明提供了一种大豆分离蛋白和金针菇多糖自组装的食用凝胶及其制备方法和应用,属于功能食品技术领域,所述制备方法包括以下步骤：1)将大豆分离蛋白与水混合、搅拌、静置获得水化蛋白质溶液；2)将金针菇多糖与水混合、搅拌、静置获得水化多糖溶液；3)将所述水化蛋白质溶液、所述水化多糖溶液和氯化钙混合、溶解获得蛋白质-多糖混合溶液；4)将所述蛋白质-多糖混合溶液置于80～90℃加热25～35min后,冷却,获得食用凝胶。本发明所述方法制备获得的食用凝胶中金针菇多糖溶解性好,活性不被破坏；食用凝胶的粘弹性和抵抗外界压力的能力明显增强。(The invention provides a self-assembled edible gel of soybean protein isolate and flammulina velutipes polysaccharide, a preparation method and application thereof, belonging to the technical field of functional food, wherein the preparation method comprises the following steps: 1) mixing the isolated soy protein with water, stirring and standing to obtain a hydrated protein solution; 2) mixing the flammulina velutipes polysaccharide with water, stirring and standing to obtain a hydrated polysaccharide solution; 3) mixing and dissolving the hydrated protein solution, the hydrated polysaccharide solution and calcium chloride to obtain a protein-polysaccharide mixed solution; 4) and heating the protein-polysaccharide mixed solution at 80-90 ℃ for 25-35 min, and cooling to obtain the edible gel. The flammulina velutipes polysaccharide in the edible gel prepared by the method disclosed by the invention is good in solubility and free from damaging the activity; the viscoelasticity and the ability to resist external pressure of the edible gel are obviously enhanced.)

1. A preparation method of self-assembled edible gel of soy protein isolate and flammulina velutipes polysaccharide is characterized by comprising the following steps:

1) mixing the isolated soy protein with water, stirring and standing to obtain a hydrated protein solution; the mass fraction of the hydrated protein solution is 0.5-1.5%;

2) mixing flammulina velutipes polysaccharide with water, stirring and standing to obtain a hydrated polysaccharide solution, wherein the mass fraction of the hydrated polysaccharide solution is 3% -5%;

3) mixing and dissolving the hydrated protein solution in the step 1), the hydrated polysaccharide solution in the step 2) and calcium chloride to obtain a protein-polysaccharide mixed solution, wherein the volumes of the hydrated protein solution and the hydrated polysaccharide solution are equal; the mass of the calcium chloride is 27-31% of the mass of the soybean protein isolate;

4) heating the protein-polysaccharide mixed solution at 80-90 ℃ for 25-35 min, and cooling to obtain edible gel;

no time sequence is defined between the step 1) and the step 2).

2. The method according to claim 1, wherein the hydrated protein solution is present in an amount of 0.8 to 1.2% by mass.

3. The method according to claim 1, wherein the hydrated polysaccharide solution is present in an amount of 3.5 to 4.5% by mass.

4. The preparation method according to claim 1, wherein the stirring in step 1) and step 2) is magnetic stirring, and the rotation speed of the stirring is 900rpm independently; the stirring time is independently 1.5-2.5 h.

5. The preparation method of claim 1, wherein the standing temperature in the step 1) and the standing temperature in the step 2) are independently 3-5 ℃, and the standing time is independently 10-14 h.

6. The method according to claim 1, wherein the amount of calcium chloride in step 3) is 29.0 to 29.6% by mass based on the amount of the soybean protein isolate.

7. The self-assembled edible gel of the soybean protein isolate and the flammulina velutipes polysaccharide obtained by the preparation method of any one of claims 1 to 6.

8. Use of the edible gel as claimed in claim 7 as a thickener or stabilizer for food products.

9. Use of the edible gel as claimed in claim 7 as a functional matrix in a food product for infant or elderly intelligence development.

10. Use according to claim 9, wherein the edible gel serves as a functional matrix for improving memory function.

Technical Field

The invention belongs to the technical field of functional foods, and particularly relates to a self-assembled edible gel of soybean protein isolate and flammulina velutipes polysaccharide, and a preparation method and application thereof.

Background

Flammulina velutipes (Flammulina velutipes) belongs to the phylum Eumycota, Basidiomycotina, Hymenomycetes, Agaricales, Orchidaceae, genus Lysimachia. Flammulina Velutipes Polysaccharide (FVP) is a water-soluble mixed polysaccharide mainly comprising dextran, and composed of various components such as mannan and xylose, and can be dissolved in aqueous solution and acid-base solution. The flammulina velutipes polysaccharide is rich in flammulina velutipes, stable in source, green and safe, and the flammulina velutipes polysaccharide is increasingly researched in recent years. The flammulina velutipes polysaccharide has good gel characteristics, and experiments show that the flammulina velutipes polysaccharide has remarkable repairing effect on the space learning and memory capacity of rats with memory function damage, and in addition, the flammulina velutipes polysaccharide can remarkably enhance the expression levels of Connexin 36, p-ERK and p-CaMK II proteins in hippocampus and cerebral cortex, so that the learning and memory functions of rats are improved, and scientific evidence is provided for the auxiliary memory function improvement effect of the flammulina velutipes polysaccharide. In recent years, intelligence-improving foods taking flammulina velutipes or flammulina velutipes polysaccharide as main components are widely developed and applied, such as flammulina velutipes cookies, flammulina velutipes polysaccharide yoghourt, flammulina velutipes health care steamed bread and the like which can assist in improving memory.

The soybean protein isolate contains 9 essential amino acids with reasonable proportion, the amino acid content of the soybean protein isolate is close to the recommended value of FAO/WHO organization, and the soybean protein isolate is high-quality complete protein and is easy to be absorbed by human bodies. The soybean protein has good functional characteristics such as gel property, emulsifying property and water-holding property, is low in price and cost, and is widely researched and applied in the food industry. The gel has an extremely important regulation and control function on the quality of the soybean protein isolate products and the derivatives thereof (such as bean curd, sausage, minced fillet and the like).

Edible gum (hydrocolloids), also called hydrophilic colloid and hydrosol, can be dissolved or dispersed in water, and under certain conditions, hydrophilic groups in the molecules, such as carboxyl, hydroxyl, amino, carboxylate, and the like, can be hydrated with water molecules to form a sticky and greasy solution or gel. In food processing, the food has the functions of thickening, viscosity increasing, adhesion, gel forming, hardness, brittleness, compactness, stable emulsification, suspension and the like, and the food can obtain various required shapes and various tastes such as hardness, softness, brittleness, stickiness, viscosity and the like, so the food is also commonly called as a food thickener, a viscosity increasing agent, a gelling agent, a stabilizer, a suspending agent, a colloid and the like. Gels have gained importance in the food industry as carriers for many flavors, nutrients and functional factors.

Although polysaccharides and proteins are common natural gel materials. However, the soy protein isolate gel has the defects of sensitivity to external environmental factors (such as metal salt, pH value, temperature and the like), poor mechanical property and the like. The flammulina velutipes polysaccharide also has the defects of poor solubility and large damage to the active ingredients of the flammulina velutipes polysaccharide in the existing food processing technology, and the development and the application of the flammulina velutipes polysaccharide gel in the food industry are limited due to the defects of single texture characteristic, poor water holding capacity, large brittleness, poor rebound resilience and the like.

Disclosure of Invention

In view of the above, the invention aims to provide a self-assembled edible gel of soy protein isolate and flammulina velutipes polysaccharide, a preparation method and an application thereof, wherein the flammulina velutipes polysaccharide in the edible gel prepared by the method has good solubility and does not destroy the activity; the viscoelasticity and the ability to resist external pressure of the edible gel are obviously enhanced.

In order to achieve the above purpose, the invention provides the following technical scheme:

the invention provides a preparation method of self-assembled edible gel of soybean protein isolate and flammulina velutipes polysaccharide, which comprises the following steps:

1) mixing the isolated soy protein with water, stirring and standing to obtain a hydrated protein solution; the mass fraction of the hydrated protein solution is 0.5-1.5%;

2) mixing flammulina velutipes polysaccharide with water, stirring and standing to obtain a hydrated polysaccharide solution, wherein the mass fraction of the hydrated polysaccharide solution is 3% -5%;

3) mixing and dissolving the hydrated protein solution in the step 1), the hydrated polysaccharide solution in the step 2) and calcium chloride to obtain a protein-polysaccharide mixed solution, wherein the volumes of the hydrated protein solution and the hydrated polysaccharide solution are equal; the mass of the calcium chloride is 27-31% of the mass of the soybean protein isolate;

4) heating the protein-polysaccharide mixed solution at 80-90 ℃ for 25-35 min, and cooling to obtain edible gel;

no time sequence is defined between the step 1) and the step 2).

Preferably, the mass fraction of the hydrated protein solution is 0.8-1.2%.

Preferably, the mass fraction of the hydrated polysaccharide solution is 3.5-4.5%.

Preferably, the stirring in the step 1) and the step 2) is magnetic stirring, and the rotation speed of the stirring is independently 900 rpm; the stirring time is independently 1.5-2.5 h.

Preferably, the standing temperature in the step 1) and the step 2) is independently 3-5 ℃, and the standing time is independently 10-14 h.

Preferably, the mass of the calcium chloride in the step 3) is 29.0-29.6% of the mass of the soybean protein isolate.

The invention provides the self-assembled edible gel of the soybean protein isolate and the flammulina velutipes polysaccharide, which is prepared by the preparation method.

The invention provides application of the edible gel as a food thickener or stabilizer.

The invention also provides application of the edible gel as a functional matrix in infant intelligence-developing food or elderly intelligence-developing food.

Preferably, the edible gel serves as a functional matrix for improving memory function.

The invention has the beneficial effects that: the edible gel prepared by self-assembling the soybean protein isolate and the flammulina velutipes polysaccharide, and the preparation method and the application thereof provided by the invention have the advantages that the hydrated protein solution and the hydrated polysaccharide solution are mixed according to the proportion for self-assembling, and compared with the single soybean protein isolate or the single flammulina velutipes polysaccharide gel, the soybean protein isolate and the flammulina velutipes polysaccharide are compounded under the condition of lower weight of raw materials to form the gel, so that the defect of poor solubility of the flammulina velutipes polysaccharide is overcome, the preparation process is mild, and the activity of the flammulina velutipes polysaccharide is favorably maintained.

The soybean protein isolate and flammulina velutipes polysaccharide edible gel prepared by the method has good viscoelasticity and disturbance resistance, the mechanical strength of the edible gel is well improved by self-assembly of the soybean protein isolate and the flammulina velutipes polysaccharide, and the viscoelasticity and the external pressure resistance of the edible gel are obviously enhanced compared with those of a single flammulina velutipes polysaccharide gel or a single flammulina velutipes polysaccharide gel.

The soybean protein isolate and the flammulina velutipes polysaccharide have natural sources, no toxic or harmful reagent is used in the extraction process, the edible gel prepared by self-assembling the soybean protein isolate and the flammulina velutipes polysaccharide has good viscoelasticity, strong water holding capacity and other physicochemical properties, can be used as a thickening agent, a stabilizing agent and the like in food processing, can assist in improving the memory capacity of the flammulina velutipes polysaccharide, and can also be used as a functional matrix to be applied to the development field of intelligence-improving foods for infants or old people.

Drawings

FIG. 1 is a schematic diagram of gels prepared by the methods provided in example 1, comparative example 2, and comparative example 4 placed in water;

FIG. 2 shows the gel of soy protein isolate, soy protein isolate in example 1: scanning electron microscope images of flammulina velutipes polysaccharide gel and flammulina velutipes polysaccharide gel with the ratio of 1: 4;

FIG. 3 is a plot of viscosity versus frequency for each of the preparations of example 2;

FIG. 4 is a plot of storage (loss) modulus versus strain sweep for each preparation of example 2;

FIG. 5 is a plot of storage modulus versus frequency sweep for each of the preparations of example 2;

FIG. 6 is a plot of the loss modulus versus frequency sweep for each of the preparations of example 2;

fig. 7 is a graph comparing gel times for different FVP concentrations.

Detailed Description

The invention provides a preparation method of self-assembled edible gel of soybean protein isolate and flammulina velutipes polysaccharide, which comprises the following steps: 1) mixing the isolated soy protein with water, stirring and standing to obtain a hydrated protein solution; the mass fraction of the hydrated protein solution is 0.5-1.5%; 2) mixing flammulina velutipes polysaccharide with water, stirring and standing to obtain a hydrated polysaccharide solution, wherein the mass fraction of the hydrated polysaccharide solution is 3% -5%; 3) mixing and dissolving the hydrated protein solution in the step 1), the hydrated polysaccharide solution in the step 2) and calcium chloride to obtain a protein-polysaccharide mixed solution, wherein the volumes of the hydrated protein solution and the hydrated polysaccharide solution are equal; the mass of the calcium chloride is 27-31% of the mass of the soybean protein isolate; 4) heating the protein-polysaccharide mixed solution at 80-90 ℃ for 25-35 min, and cooling to obtain edible gel; no time sequence is defined between the step 1) and the step 2).

In the present invention, the soy protein isolate is mixed with water, stirred, and allowed to stand to obtain a hydrated protein solution. In the present invention, the soy protein isolate is a complete protein of soy origin, comprising 20 amino acids; the source of the isolated soy protein is not particularly limited, and the isolated soy protein can be obtained by adopting conventional commercial products in the field, and in the specific implementation process of the invention, the isolated soy protein is purchased from Beijing Solebao scientific and technological Co., Ltd, and the content of protein in the isolated soy protein is more than or equal to 88%. In the invention, the mass fraction of the hydrated protein solution is 0.5-1.5%, preferably 0.8-1.2%, and more preferably 1%; in the invention, the stirring is preferably magnetic stirring, and the rotating speed of the stirring is preferably 900 rpm; the stirring time is preferably 1.5-2.5 h, and more preferably 2.0 h. In the invention, the standing temperature is preferably 3-5 ℃, and more preferably 4 ℃; the standing time is preferably 10-14 h, and more preferably 12 h.

In the invention, the flammulina velutipes polysaccharide is mixed with water, stirred and stood to obtain a hydrated polysaccharide solution. In the present invention, the mass fraction of the hydrated polysaccharide solution is 3% to 5%, preferably 3.5% to 4.5%, more preferably 3.8% to 4.2%, and most preferably 4.0%. In the invention, the stirring is preferably magnetic stirring, and the rotating speed of the stirring is preferably 900 rpm; the stirring time is preferably 1.5-2.5 h, and more preferably 2.0 h. In the invention, the standing temperature is preferably 3-5 ℃, and more preferably 4 ℃; the standing time is preferably 10-14 h, and more preferably 12 h. In the invention, the flammulina velutipes polysaccharide is water-soluble mixed polysaccharide extracted from flammulina velutipes sporocarp, can be dissolved in aqueous solution and acid-base solution, and is edible fungus polysaccharide which is mainly composed of glucan, mannan, xylose and other components. The sources of the flammulina velutipes polysaccharide are not particularly limited, and the flammulina velutipes polysaccharide can be prepared from conventional commercial products or prepared by self; the total sugar content of the flammulina velutipes polysaccharide is preferably more than or equal to 85%. In the invention, the method for preparing the flammulina velutipes polysaccharide by self is preferably a water extraction and alcohol precipitation method; the specific steps are preferably as follows: after the needle mushroom is leached by water, the needle mushroom polysaccharide is obtained by ethanol precipitation, dialysis and drying. In the invention, the leaching temperature is preferably 75-80 ℃, and more preferably 80 ℃; the leaching time is preferably 3-5 h, and more preferably 4 h; the molecular weight cut-off of the dialysis bag for dialysis is preferably 3500 Da; the drying is preferably vacuum drying.

After the hydrated protein solution and the hydrated polysaccharide solution are obtained, the hydrated protein solution, the hydrated polysaccharide solution and calcium chloride are mixed and dissolved to obtain a protein-polysaccharide mixed solution. In the present invention, the hydrated protein solution and the hydrated polysaccharide solution are equal in volume. In the present invention, it is preferable that the hydrated protein solution is mixed with the hydrated polysaccharide solution and then mixed with calcium chloride. In the present invention, the mass of the calcium chloride is 27% to 31%, preferably 29.0% to 29.6%, and more preferably 29.3% of the mass of the soybean protein isolate. The calcium chloride is not particularly limited, and the calcium chloride can be obtained by adopting a conventional analytical pure product sold on the market in the field; in the present invention, the calcium chloride functions to enhance the crosslinking strength of the prepared gel in the form of the presence of calcium bridges.

After the protein-polysaccharide mixed solution is obtained, the protein-polysaccharide mixed solution is heated at the temperature of 80-90 ℃ for 25-35 min and then cooled to obtain the edible gel. In the invention, the heating temperature is preferably 82-88 ℃, and more preferably 85 ℃; the heating time is preferably 28-32 ℃, and more preferably 30 ℃. In the present invention, the heating is preferably performed by water bath heating. The cooling method is not particularly limited, and a conventional cooling method in the field is adopted, so that rapid cooling can be realized; in the specific implementation process of the invention, the cooling is performed by using ice water.

The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

The SPI used in the embodiment of the invention is purchased from Beijing Solaibao science and technology Limited, and the protein content is more than or equal to 88 percent; the flammulina velutipes polysaccharide used in the embodiment of the invention is prepared by a water extraction and alcohol precipitation method, and the specific extraction conditions are as follows: leaching needle mushroom dry powder in a hot water bath at 80 ℃ for 4h according to a liquid-material ratio of 1:80, centrifuging at 10000rpm to obtain supernatant, adding 95% ethanol with 5 times volume of the supernatant for precipitating overnight, dialyzing the obtained precipitate for 24h through a 3500Da pore diameter dialysis bag, changing water every 2-3h, and drying the dialyzate in vacuum to obtain needle mushroom polysaccharide, wherein the total sugar content of the needle mushroom polysaccharide is more than or equal to 85%.