A method for preparing interpenetrating cross-linked network emulsion gel by biological and physical methods

Abstract

The invention discloses a method for preparing a biological and physical interpenetrating cross-linked network emulsion gel, using TG cross-linked gelatin as the first polymer network and Fe 3+ The cross-linked CMC-Na is the second polymer network, with Ca 2+ The cross-linked SA is the third polymer network, which is catalyzed by biological enzymes and then by Fe 3 Solution, Ca 2+ The solution cross-linking can form a triple interpenetrating network structure, which is convenient to operate and simple in process. The synergistic combination of bio-physical cross-linking gives the gel good comprehensive mechanical properties and thermal stability. The raw materials of the invention are widely available, cheap and easy to obtain, and have good biocompatibility. The prepared emulsion gel is resistant to high temperatures and has high gel strength. It has broad practical application prospects and has great potential in the fields of food, medicine, materials, etc.

Description

Technical Field

[0001] The invention relates to the technical field of emulsion gel preparation, in particular to a method for preparing an interpenetrating cross-linked network emulsion gel by biological and physical methods. Background Art

[0002] Emulsion gel refers to a semi-solid food system with a three-dimensional network structure in which oil droplets are dispersed in a gel matrix. Emulsion gel has the advantages of both emulsions and hydrogels. The emulsion droplets can dissolve fat-soluble or amphiphilic active substances, and its three-dimensional network structure can well fix and protect the droplets, making it a good transport carrier for bioactive substances. Compared with emulsions, emulsion gels have a strong network structure, which can not only maintain the stability of food during transportation and storage, but also efficiently carry bioactive substances and achieve a slow release effect. Emulsion gels can be formed by gelling the continuous phase of the emulsion or aggregating the emulsion droplets through heating protein denaturation, enzyme action, salt ion action or physical methods.

[0003] Gelatin (GA) is a mixture of peptides and proteins obtained by partial hydrolysis of animal collagen. It has good amphiphilic properties, excellent biocompatibility, is easy to obtain, and has low production costs. After cooling, the gelatin solution self-aggregates through non-covalent interactions to form a gel. Since gelatin only relies on non-covalent interactions such as hydrogen bonds to form a gel, its gel strength and thermal stability are poor. After heating, the gelatin's gel properties will decrease. Glutamine aminotransferase (TGase) is a monomer protein with an active center that can catalyze intramolecular and intermolecular covalent cross-linking of protein polypeptides, thereby improving the structure and properties of proteins, such as improving the foaming, emulsification, emulsification stability, thermal stability, water retention and gelling ability of proteins, thereby improving the flavor, taste, texture and appearance of food. TGase can catalyze the cross-linking between glutamine and lysine in gelatin molecules to form covalent cross-linking bonds to improve the emulsification, emulsification stability and thermal stability of gelatin, and promote its application in the food industry.

[0004] Sodium alginate (SA) is a safe natural anionic polysaccharide that can crosslink with divalent metal cations to form a gel. Compared with other hydrogel materials, sodium alginate hydrogel is non-toxic and has high biocompatibility. It is widely used in various biotechnology fields such as gel tissue engineering of artificial bone and skin, drug delivery, wound dressing, packaging, etc. The preparation of sodium alginate hydrogel is usually based on ionic crosslinking, and calcium carbonate or calcium chloride solution is often used as the calcium source. 2+It can form an "egg-box" structured hydrogel with the carboxyl group of sodium alginate, but the crosslinking of the gel prepared by this method is not uniform enough, and it is easy to have local excessive crosslinking, poor mechanical properties, low swelling rate, and low strength of the formed gel. It is difficult to maintain the inherent shape in the hydrated state and is easy to break. These shortcomings seriously limit its application. Therefore, it is necessary to develop sodium alginate gel with high crosslinking strength to expand its further application.

[0005] Sodium carboxymethyl cellulose (CMC-Na) is a straight-chain starch with many hydroxyl and carboxyl groups. It is widely available and low-cost. It is hygroscopic and can absorb a large amount of water. Therefore, the hydrogel prepared with sodium carboxymethyl cellulose has many excellent properties such as high water content, good biodegradability, and non-toxicity. It is widely used in agriculture and biology. Since sodium carboxymethyl cellulose molecules have a large number of hydroxyl and carboxyl groups, they can form a three-dimensional polymer network structure with divalent or trivalent metal cations through electrostatic interaction. 3+ The aqueous solution reacts to form a hydrogel with high water content and good mechanical strength. 3+ It coordinates with the carboxymethyl group in sodium carboxymethyl cellulose to cross-link it to form a three-dimensional network structure, and wraps a large number of water molecules to eventually form a gel.

[0006] Traditional gels are formed by a single physical cross-linked network, lack good mechanical properties, have low strength, poor toughness, are soft and brittle, and are difficult to meet the needs of practical applications. Interpenetrating network gels are polymer blends formed by two or more polymer networks that interpenetrate or entangle each other. Interpenetrating cross-linked network gels are composed of independent and interpenetrating gel systems, and have better adsorption performance, mechanical properties and stability than traditional single system gels. Summary of the invention

[0007] The present invention prepares a biophysical cross-linked triple interpenetrating network gel GA / CMC-Na / SA, using TG cross-linked gelatin as the first polymer network and Fe 3+ The cross-linked CMC-Na is the second polymer network with Ca 2+ The cross-linked SA is the third polymer network, which is catalyzed by biological enzymes and then by Fe 3 Solution, Ca 2+ The solution cross-linking can form a triple interpenetrating network structure, which is convenient to operate and simple in process. The synergistic combination of biological and physical cross-linking gives the gel good comprehensive mechanical properties and thermal stability.

[0008] The technical solution of the present invention is as follows:

[0009] A method for preparing a biological and physical interpenetrating cross-linked network emulsion gel comprises the following steps:

[0010] (1) dissolving whey protein and maltodextrin in water as an aqueous phase, mixing the aqueous phase with an oil phase, and subjecting the mixture to high-speed shearing and high-pressure homogenization to obtain an emulsion;

[0011] Preferably, the oil phase is one or more of corn oil, butter, and coconut oil;

[0012] The preferred mass ratio of whey protein, maltodextrin, water and oil phase is 1:4:10:5;

[0013] Preferably, the high-speed shearing condition is 18000rpm, 60s; the high-pressure homogenization condition is 30Mpa, 2 times;

[0014] (2) mixing the gelatin solution, the CMC-Na solution and the sodium alginate solution to obtain a mixed gelatin solution;

[0015] Specifically, the preparation method of the gelatin solution is: adding gelatin to water at a solid-liquid ratio of 1:3, swelling at room temperature for 0.5 hours, heating to 50-60° C. and stirring for 20 minutes to obtain a gelatin solution;

[0016] The preparation method of the CMC-Na solution is as follows: adding CMC-Na to water at a solid-liquid ratio of 1:90, and placing in a water bath at 90° C. for 0.5 h to obtain the CMC-Na solution;

[0017] The preparation method of the sodium alginate solution is as follows: sodium alginate is added to water at a solid-liquid ratio of 1:19, stirred for 60 minutes, and fully hydrated overnight to obtain a sodium alginate solution;

[0018] The mass ratio of the gelatin solution, CMC-Na solution and sodium alginate solution is 1:1:8 to 2:1:1;

[0019] (3) mixing the emulsion obtained in step (1) with the mixed gel obtained in step (2), and shearing them using a high-speed disperser to obtain an emulsion gel;

[0020] The mass ratio of the latex to the mixed glue is 1:1 to 4:1;

[0021] The shearing condition of the high-speed disperser is 18000rpm, 60s;

[0022] (4) adding TG enzyme and FeCl3 solution to the emulsion gel obtained in step (3), and crosslinking at 45-55° C. for 1-4 hours to obtain a crosslinked emulsion gel;

[0023] The enzyme activity of the TG enzyme is 200u / ml, and the amount of TG enzyme added is 2% of the mass of gelatin;

[0024] The mass concentration of the FeCl3 solution is 1%, and the amount of the FeCl3 solution added is 0.08-0.2% of the mass of the emulsion gel;

[0025] (5) The cross-linked emulsion gel in step (4) was cooled to 0°C in an ice water bath and then immersed in Ca 2+ After 24 hours in the solution, an interpenetrating cross-linked network latex gel was obtained;

[0026] The Ca 2+ The solution is made by dissolving calcium chloride in water, where Ca 2+ The mass concentration is 1%.

[0027] The beneficial effects of the present invention are:

[0028] The gelatin, sodium carboxymethyl cellulose and sodium alginate required in the preparation method of the present invention are widely available, cheap and easy to obtain, and have good biocompatibility. The prepared emulsion gel is high temperature resistant and has high gel strength, has broad practical application prospects, and has great potential in the fields of food, medicine, materials, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart for the preparation of interpenetrating cross-linked network emulsion gel.

[0030] Figure 2 This is a process flow chart of interpenetrating cross-linked network emulsion gel.

[0031] Figure 3 These are the images of Comparative Example 1 and Example 1 after being treated at high temperature (100°C).

[0032] Figure 4 These are the DSC graphs of Comparative Example 1 and Example 1. DETAILED DESCRIPTION

[0033] The present invention is further described below by means of specific embodiments, but the protection scope of the present invention is not limited thereto.

[0034] Comparative Example 1

[0035] (1) 2 g of whey protein and 8 g of maltodextrin were added to 20 g of water, and the mixture was stirred magnetically for 20 min. 10 g of corn oil was added, and the mixture was subjected to high-speed shearing at 18,000 rpm for 60 s and high-pressure homogenization at 30 MPa for 2 times to obtain an emulsion.

[0036] (2) Add 15 g of gelatin to 45 g of water, heat in a water bath at 55°C and stir for 20 min until the gelatin fully absorbs water and swells, to obtain a gelatin solution. Add 0.5 g of CMC-Na to 45 g of water, and heat in a water bath at 90°C for 0.5 h to obtain a CMC-Na solution.

[0037] (3) Add 5 g of sodium alginate into 95 g of water, stir thoroughly for 60 min, and allow to fully hydrate overnight to obtain a sodium alginate solution.

[0038] (4) 10 g of gelatin solution, 10 g of CMC-Na solution and 20 g of sodium alginate solution were mixed in a ratio of 1:1:2 to obtain a mixed gelatin solution.

[0039] (5) 40 g of the emulsion and 40 g of the mixed gel were mixed in a ratio of 1:1 and sheared using a high-speed disperser at a high speed dispersion condition of 18,000 rpm for 60 s to obtain an emulsion gel.

[0040] (6) Cool the emulsion gel to 0°C in an ice water bath.

[0041] (7) Soak the completely solidified emulsion gel in an aqueous solution for 24 hours.

[0042] Example 1

[0043] (1) 2 g of whey protein and 8 g of maltodextrin were added to 20 g of water, and the mixture was stirred magnetically for 20 min. 10 g of corn oil was added, and the mixture was subjected to high-speed shearing at 18,000 rpm for 60 s and high-pressure homogenization at 30 MPa for 2 times to obtain an emulsion.

[0044] (2) Add 15 g of gelatin to 45 g of water, heat in a water bath at 55°C and stir for 20 min until the gelatin fully absorbs water and swells, to obtain a gelatin solution. Add 0.5 g of CMC-Na to 45 g of water, and heat in a water bath at 90°C for 0.5 h to obtain a CMC-Na solution.

[0045] (3) Add 5 g of sodium alginate into 95 g of water, stir thoroughly for 60 min, and allow to fully hydrate overnight to obtain a sodium alginate solution.

[0046] (4) 10 g of gelatin solution, 10 g of CMC-Na solution, and 20 g of sodium alginate solution were mixed in a ratio of 1:1:2 to obtain a mixed gelatin solution.

[0047] (5) 40 g of the emulsion and 40 g of the mixed gel were mixed at a ratio of 1:1 and sheared using a high-speed disperser at a high speed dispersion condition of 18,000 rpm for 60 s to obtain an emulsion gel.

[0048] (6) Add 0.05 g of TG enzyme and 0.1 ml of 1% FeCl3 solution to the emulsion gel, and crosslink at 50°C for 2 h to obtain a crosslinked emulsion gel.

[0049] (7) Cool the cross-linked emulsion gel to 0°C in an ice water bath.

[0050] (8) Soak the completely solidified emulsion gel in Ca2+ 1% CaCl2 solution for 24h.

[0051] The test method for the emulsion gel is as follows:

[0052] Thermal stability test

[0053] 15 mg of the sample was weighed, the protective gas was nitrogen, the gas flow rate was 30 mL / min, the sample was tested in a differential scanning calorimeter and the temperature was increased from 30°C to 300°C at a rate of 10°C / min.

[0054] The results are as follows Figure 4 As shown, the samples all undergo endothermic reactions at high temperatures, and all have an obvious absorption peak between 100°C and 120°C. The thermal denaturation midpoint temperature of Example 1 is higher than that of Comparative Example 1, indicating that the thermal stability of Example 1 is greater than that of Comparative Example 1. This is because Example 1 forms a triple interpenetrating network structure through crosslinking, so a higher temperature is required to destroy the structure of the gel network.

Claims

1. A method for preparing a biological and physical interpenetrating cross-linked network emulsion gel, characterized in that: The steps include: (1) dissolving whey protein and maltodextrin in water as an aqueous phase, mixing the aqueous phase with an oil phase, and subjecting the mixture to high-speed shearing and high-pressure homogenization to obtain an emulsion; The oil phase is one or more of corn oil, butter, and coconut oil; (2) mixing the gelatin solution, the CMC-Na solution and the sodium alginate solution to obtain a mixed gelatin solution; (3) mixing the emulsion obtained in step (1) with the mixed gel obtained in step (2), and shearing them using a high-speed disperser to obtain an emulsion gel; (4) adding TG enzyme and FeCl3 solution to the emulsion gel obtained in step (3), and crosslinking at 45-55° C. for 1-4 hours to obtain a crosslinked emulsion gel; (5) The cross-linked emulsion gel in step (4) was cooled to 0°C in an ice water bath and then immersed in Ca 2+ After 24 hours in the solution, an interpenetrating cross-linked network latex gel was obtained.

2. The method for preparing the biological and physical interpenetrating cross-linked network emulsion gel according to claim 1, characterized in that: In step (1), the mass ratio of whey protein, maltodextrin, water and oil phase is 1:4:10:

5.

3. The method for preparing the biological and physical interpenetrating cross-linked network emulsion gel according to claim 1, characterized in that: In step (1), the high-speed shearing condition is 18000 rpm, 60 s; the high-pressure homogenization condition is 30 MPa, 2 times.

4. The method for preparing the biological and physical interpenetrating cross-linked network emulsion gel according to claim 1, characterized in that: In step (2), the preparation method of the gelatin solution is: adding gelatin to water at a solid-liquid ratio of 1:3, swelling at room temperature for 0.5h, heating to 50-60°C and stirring for 20min to obtain a gelatin solution; the preparation method of the CMC-Na solution is: adding CMC-Na to water at a solid-liquid ratio of 1:90, bathing at 90°C for 0.5h to obtain a CMC-Na solution; the preparation method of the sodium alginate solution is: adding sodium alginate to water at a solid-liquid ratio of 1:19, stirring for 60min, and fully hydrating overnight to obtain a sodium alginate solution; The mass ratio of the gelatin solution, the CMC-Na solution and the sodium alginate solution is 1:1:8 to 2:1:

1.

5. The method for preparing the biological and physical interpenetrating cross-linked network emulsion gel according to claim 1, characterized in that: In step (3), the mass ratio of the latex to the mixed glue is 1:1 to 4:

1.

6. The method for preparing the biological and physical interpenetrating cross-linked network emulsion gel according to claim 1, characterized in that: In step (3), the shearing condition of the high-speed disperser is 18000 rpm for 60 s.

7. The method for preparing the biological and physical interpenetrating cross-linked network emulsion gel according to claim 1, characterized in that: In step (4), the enzyme activity of the TG enzyme is 200u / ml, and the amount of TG enzyme added is 2% of the mass of gelatin.

8. The method for preparing the biological and physical interpenetrating cross-linked network emulsion gel according to claim 1, characterized in that: In step (4), the mass concentration of the FeCl3 solution is 1%, and the amount of FeCl3 solution added is 0.08-0.2% of the mass of the emulsion gel.

9. The method for preparing the biological and physical interpenetrating cross-linked network emulsion gel according to claim 1, characterized in that: In step (5), the Ca 2+ The solution is made by dissolving calcium chloride in water, where Ca 2+ The mass concentration is 1%.

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