Preparation method of W / O / W dual emulsion based on myofibrillar protein / polyglycerol ricinoleate co-stabilization

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a preparation method of a W / O / W dual emulsion based on myofibrillar protein / polyglycerol ricinoleate co-stabilization. The poly myofibrillar protein (5-15 mg / mL) as an amphiphilic emulsifier and the polyglycerol ricinoleate (2-6%, w / w) synergistically enhance the interface stability of the emulsion, the prepared W / O / W dual emulsion can be stably stored at room temperature for at least 7 days, and the light stability and the heat stability of water-soluble bioactive substances encapsulated in the emulsion can be remarkably improved. Good amphipathy and emulsifying capacity of the myofibrillar protein are utilized, the use of the synthetic emulsifier is reduced, the stability of the W / O / W emulsion and the protectiveness of a coating substance are improved, technical support is provided for preparation of the stable W / O / W dual emulsion, and technical guarantee is provided for application of the stable W / O / W dual emulsion to emulsified food processing.

Description

Technical Field

[0001] The present invention belongs to the technical field of food processing, and particularly relates to a preparation method of a W / O / W double emulsion co-stabilized by myofibrillar protein / polyglycerol ricinoleate. Background Art

[0002] An emulsion is a relatively stable colloidal dispersion system formed by two or more immiscible liquids with the emulsifier stabilizing the interface and through homogenization and other treatments. Traditional emulsion systems are divided into water-in-oil (W / O) and oil-in-water (O / W) emulsions according to the composition of the dispersed phase and the continuous phase. Emulsions are widely used in the food industry. The preparation of products such as ice cream, sauces, and emulsified meat products is related to a stable emulsion dispersion system. For many natural bioactive substances, such as flavors, pigments, antibacterial agents, etc., they are also made into emulsions to improve their stability in food applications. However, traditional emulsions mostly belong to a coarse dispersion system and are in a thermodynamically unstable state. They will produce phenomena such as gravitational stratification, flocculation, and coalescence over time. Therefore, the application of traditional emulsions in the food field is limited to a certain extent.

[0003] A double emulsion refers to a system in which the droplets inside the emulsion contain smaller emulsions. The common types are water-in-oil-in-water (W / O / W) and oil-in-water-in-oil (O / W / O). In food processing, the aqueous phase system is more common. Therefore, the W / O / W double emulsion with water as the continuous phase is more widely used. Compared with traditional O / W emulsions, the inner phase of the W / O / W emulsion contains both an oil phase and an aqueous phase, and can encapsulate and transport both lipophilic and hydrophilic components at the same time. It has more types and better preparation controllability, so it has broad application prospects in the fields of food, cosmetics, medicine, etc. Especially for water-soluble active substances, they can be encapsulated in the inner aqueous phase, not only significantly improving the capacity, but also significantly enhancing the protection. However, compared with traditional emulsions, the stability of the W / O / W emulsion still needs to be improved. Facing the increasingly complex food processing application scenarios, the stability of existing W / O / W emulsions still cannot meet the requirements. Therefore, it is very necessary to develop a more stable W / O / W double emulsion preparation technology.

[0004] Emulsifiers play a crucial role in the formation of W / O / W double emulsions, including stabilizing the oil-water interface, controlling the formation of droplets at all levels of the emulsion, and the overall stability of the emulsion. The main reasons for the instability of W / O / W emulsions are the aggregation of oil droplets, the polymerization of the inner aqueous phase, and the migration of the inner aqueous phase to the outer aqueous phase, etc. Traditional W / O / W double emulsion preparations mostly use a single emulsifier, but its applicability is limited and it is not conducive to the preparation of high-stability multifunctional emulsions. Therefore, in recent years, the combined use of two or more emulsifiers to enhance the stability and functionality of the oil-water interface has become a research hotspot.

[0005] In addition, with the increasing emphasis on health, the use of "label-friendly" natural biomolecules to replace chemically synthesized surfactants in food is a future development trend. Natural biomolecules such as proteins, polysaccharides, and phospholipids are not only highly biocompatible but also abundant in content, making them good sources of safe and green emulsifiers. Among them, myofibrillar protein has excellent amphiphilicity and high structural flexibility, which is conducive to the formation of a viscoelastic interfacial film. Although the emulsifying ability of proteins is lower than that of small molecule emulsifiers, myofibrillar protein can form a protein film with strong viscoelasticity at the interface, resist mechanical stress, and provide electrostatic repulsion and steric hindrance barriers, thereby enhancing the stability of the emulsion more comprehensively.

[0006] Currently, there is no report on the method of co-stabilizing W / O / W double emulsions with myofibrillar protein and small molecule emulsifiers. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the present invention uses the amphiphilicity of myofibrillar protein to synergistically enhance the emulsifying property of polyglycerol ricinoleate to solve the instability problems of W / O / W double emulsions during encapsulation and storage. The present invention develops a preparation method of W / O / W double emulsions co-stabilized by myofibrillar protein and polyglycerol ricinoleate. The prepared emulsions not only reduce the dosage of synthetic small molecule emulsifiers, but also improve the emulsion stability, enhance the commercial value of the emulsions, extend their shelf life, and expand the application scope of the emulsions, such as improving the color protection, freshness preservation, and antioxidant properties of emulsified meat products.

[0008] To achieve the invention purpose, the present invention adopts the following technical solutions:

[0009] The first object of the present invention is to provide a preparation method of W / O / W double emulsions co-stabilized by myofibrillar protein / polyglycerol ricinoleate, comprising the following steps:

[0010] a. Using an aqueous solution containing the active substance as the internal aqueous phase; adding polyglycerol ricinoleate to soybean oil and myofibrillar protein to phosphate buffer solution, and mixing and homogenizing the two to obtain the oil phase;

[0011] b. Mixing and homogenizing the internal aqueous phase prepared in step a with the oil phase to obtain a W / O emulsion;

[0012] c. Dissolving gum arabic and xanthan gum in water to obtain the external aqueous phase;

[0013] d. Mixing and homogenizing the W / O emulsion prepared in step b with the external aqueous phase prepared in step c to obtain a stable W / O / W double emulsion.

[0014] Furthermore, the active substance in step a is a water-soluble bioactive ingredient;

[0015] Preferably, the water-soluble bioactive ingredient refers to an ingredient with color protection, antioxidant, and anti-inflammatory activities.

[0016] Preferably, the active substance is selected from one or more of betanin, amaranth red, monascus red, sorghum red, and rose red.

[0017] Furthermore, the mass ratio concentration of polyglycerol ricinoleate in soybean oil in step a is 2-6% (w / w), and the mass concentration of myofibrillar protein in phosphate buffer in step a is 5-15 mg / mL; the volume ratio of soybean oil to phosphate buffer containing myofibrillar protein is 1:4-3:7;

[0018] Preferably, the phosphate buffer is 20 mmol / L K2HPO4 / KH2PO4, 0.6 mol / L NaCl, pH 7.0.

[0019] Furthermore, the homogenization conditions in step a are 6000-8000 rpm, and the homogenization time is 1-3 min.

[0020] Furthermore, the homogenization conditions in step b are 8000-15000 rpm, and the homogenization time is 2-4 min.

[0021] Furthermore, the volume ratio of the internal aqueous phase to the oil phase in step b is 1:4-3:5.

[0022] Furthermore, the mass ratio concentrations of gum arabic and xanthan gum in water in step c are 1-3% (w / v) and 0.2-0.4% (w / v), respectively.

[0023] Furthermore, the dissolution conditions in step c are 45-60 °C, and stirring is carried out until dissolution.

[0024] Preferably, the stirring time is 90-150 min.

[0025] Furthermore, the homogenization conditions in step d are 8000-10000 rpm, and the homogenization time is 1-3 min.

[0026] Furthermore, it is characterized in that: the volume ratio of the W / O emulsion to the external aqueous phase in step d is 1:4-3:5.

[0027] The second object of the present invention is to provide a co-stabilized W / O / W double emulsion prepared by the aforementioned preparation method.

[0028] The third object of the present invention is to provide the application of the aforementioned W / O / W double emulsion in the preparation of emulsified meat products, and the W / O / W double emulsion is used as a combination of one or more of an emulsifier, a color protection agent, a preservative, and an antioxidant.

[0029] The present invention has the following beneficial effects:

[0030] 1. The present invention uses polyglycerol ricinoleate and myofibrillar protein as a synergistic emulsifier to construct a stable oil-water interface, and uses gum arabic and xanthan gum to construct the external aqueous phase. The prepared W / O / W double emulsion has high stability and can be stored for a long time.

[0031] 2. The present invention utilizes the good amphiphilicity and charge-induced repulsion characteristics of myofibrillar protein, in combination with polyglycerol ricinoleate, to provide better interaction sites and protection for bioactive molecules.

[0032] 3. The preparation process of the present invention is simple, the preparation conditions are mild, the use of synthetic emulsifiers is reduced, and the prepared W / O / W meets the requirements of green labels and can be widely used in food processing. Description of the Drawings

[0033] Figure 1 Storage stability diagrams of (a) W / O; (b) W / O / W emulsions prepared with different emulsifier ratios;

[0034] Figure 2 Potential diagrams of W / O / W double emulsions prepared with different emulsifier ratios; where a - f indicate significant differences in the potential values of W / O / W double emulsions prepared with different emulsifier ratios (P < 0.05);

[0035] Figure 3 Particle size distribution diagrams of W / O / W double emulsions prepared with different emulsifier ratios;

[0036] Figure 4 Effect of different myofibrillar protein concentrations on the kinetic stability of W / O emulsions;

[0037] Figure 5 Effect of different polyglycerol ricinoleate addition amounts on the kinetic stability of W / O / W emulsions;

[0038] Figure 6 Microscopic structure diagrams of W / O / W double emulsions prepared with different emulsifier ratios;

[0039] Figure 7 W / O / W double emulsions prepared with different water-soluble bioactive components;

[0040] Figure 8 Effect of different light exposure durations on the degradation rate of bioactive substances;

[0041] Figure 9 Effect of different temperature treatments on the degradation rate of bioactive substances. Detailed Embodiments

[0042] The present invention will be further explained below in conjunction with embodiments, but the embodiments do not limit the present invention in any form.

[0043] Example 1

[0044] Simultaneously use polyglycerol ricinoleate (PGPR) and myofibrillar protein (MP) as co-emulsifiers, and their addition amounts are as follows:

[0045]

[0046] In the table are the mass ratio concentrations of polyglycerol ricinoleate in soybean oil and the mass concentrations of myofibrillar protein in phosphate buffer. The myofibrillar protein is first dissolved in phosphate buffer (20 mmol / L K2HPO4 / KH2PO4, 0.6 mol / L NaCl, pH 7.0) and then homogenized with polyglycerol ricinoleate.

[0047] The specific operation steps are as follows:

[0048] a. Dissolve the bioactive substance (take betanin as an example) at 4% (w / v) in water as the internal aqueous phase, add polyglycerol ricinoleate and myofibrillar protein to soybean oil according to the ratio in the above table and homogenize (8000 rpm, 2 min) to obtain the oil phase, where the volume ratio of soybean oil to phosphate buffer containing myofibrillar protein is 3:7;

[0049] b. Mix the internal aqueous phase and the oil phase at a volume ratio of 3:5 and homogenize (15000 rpm, 3 min) to obtain a W / O emulsion;

[0050] c. Dissolve 2% (w / v) gum arabic and 0.3% (w / v) xanthan gum in water (50 °C, stir for 120 min until dissolved) to obtain the external aqueous phase;

[0051] d. Mix the W / O emulsion and the external aqueous phase at a ratio of 3:5 and homogenize (10000 rpm, 2 min) to obtain a stable W / O / W double emulsion, and store it at 4 °C.

[0052] Take pictures of the prepared W / O / W double emulsion on the 0th and 7th days to observe the storage stability, and measure the particle size, zeta potential, microstructure of the W / O / W double emulsion and the kinetic stability of the W / O emulsion.

[0053] The experimental results are as Figures 1 - 6 shown. The combined use of polyglycerol ricinoleate and myofibrillar protein can improve the stability of W / O ( Figure 1 a) and W / O / W emulsions ( Figure 1 b), and the addition of myofibrillar protein can increase the absolute value of the zeta potential of the W / O / W double emulsion ( Figure 2), with the increase of myofibrillar protein concentration, the particle size of the emulsion decreased significantly ( Figure 3 ). When the concentration of myofibrillar protein was the same, increasing the addition amount of polyglycerol ricinoleate in soybean oil to 4% or more could improve the emulsion stability ( Figure 4 ); when the addition amount of polyglycerol ricinoleate was 4%, the concentration of myofibrillar protein in phosphate buffer was 10 mg / mL or more, and the emulsion was the most stable ( Figure 5 ). Through microscopic observation, the microstructural diagram of the W / O / W double emulsion showed that most of the emulsion droplets were spherical, and the small inner aqueous phase droplets were clearly visible. Compared with the emulsion without myofibrillar protein, the particle size increased significantly after adding myofibrillar protein, and decreased slightly with the increase of myofibrillar protein concentration ( Figure 6 ), combined with Figure 5 analysis, although the particle size increased after adding myofibrillar protein, the stability was improved. Except for betanin, adding other active substances such as amaranth red, monascus red, sorghum red, rose red, etc. at 4% (w / v) all showed a stable emulsion state and could be used to prepare the co-stabilized W / O / W double emulsion described in the present invention ( Figure 7 ).

[0054] Example 2

[0055] Using the myofibrillar protein / polyglycerol ricinoleate co-stabilized W / O / W double emulsion optimized in Example 1 as an encapsulation system for bioactive substances (taking betanin as an example), with the aqueous solution of the bioactive substance as a control, the effects of light exposure duration ( Figure 8 ) and temperature ( Figure 9 ) on the degradation rate of betanin were investigated.

[0056] The experimental steps were as follows: 10 mL of betanin solution and betanin W / O / W emulsion were respectively taken and sealed and heated in different water bath temperatures (60, 70, 80, 90 °C) for 30 min. After the water bath, it was immediately cooled to room temperature. The emulsion samples were centrifuged (10000 g × 10 min), and then the lower aqueous phase was filtered through a 0.45 μm aqueous filter to remove fat globules, and the loss rate (%) of the pigment after heating was calculated. The betanin solution and betanin W / O / W emulsion were sealed and placed under a fluorescent lamp for continuous irradiation, and samples were taken on the 0th, 1st, 2nd, 3rd, 4th, and 5th days to measure the loss rate (%) of the pigment.

[0057] The experimental results showed that under the condition of 20 W incandescent light irradiation, or at high temperatures of 60 °C to 90 °C, after encapsulating the bioactive substance with the myofibrillar protein / polyglycerol ricinoleate co-stabilized W / O / W double emulsion, the degradation rate of the encapsulated betanin was significantly inhibited ( Figure 8 、 9) This indicates that the W / O / W double emulsion of the present invention not only has a good encapsulation effect, but also has an obvious effect on improving the stability of bioactive substances.

[0058] Comparative Example 1 Comparative example without adding myofibrillar protein

[0059] A method for preparing a W / O / W double emulsion co-stabilized with polyglyceryl ricinoleate, comprising the following steps:

[0060] a. Dissolve the bioactive substance (taking betanin as an example) at 4% (w / v) in water as the inner aqueous phase, and add 2%, 4%, 6% (w / w) of polyglyceryl ricinoleate to soybean oil and homogenize (8000 rpm, 2 min) to obtain the oil phase;

[0061] b. Mix the inner aqueous phase and the oil phase at a ratio of 3:5 and homogenize (15000 rpm, 3 min) to obtain a W / O emulsion;

[0062] c. Dissolve 2% (w / v) of gum arabic and 0.3% (w / v) of xanthan gum in water (50 °C, 120 min) to obtain the outer aqueous phase;

[0063] d. Mix the W / O emulsion and the outer aqueous phase at a ratio of 3:5 and homogenize (10000 rpm, 2 min) to obtain a stable W / O / W double emulsion, and store it at 4 °C.

[0064] Take pictures of the prepared W / O / W double emulsion on the 0th and 7th days to observe the storage stability ( Figure 1 ), and measure the potential ( Figure 2 ), particle size ( Figure 3 ) of the W / O / W double emulsion and the kinetic stability ( Figure 4 ) of the W / O emulsion. The experimental results show that the W / O emulsion prepared with polyglyceryl ricinoleate as the emulsifier has poor stability. As the addition amount of polyglyceryl ricinoleate increases, the volume average particle size of the W / O / W double emulsion increases significantly, and the potential value changes insignificantly.

[0065] Therefore, the present invention uses polyglyceryl ricinoleate and myofibrillar protein as co-emulsifiers to improve the interfacial stability of the emulsion and prepares a highly stable W / O / W double emulsion.

[0066] The protection scope of the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, and improvements made within the spirit and scope of the concept of the present invention are included in the protection scope of the present invention.

[0067] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a W / O / W double emulsion based on co-stabilization of myofibrillar protein / polyglycerol ricinoleate, characterized in that: The following steps are involved: a. The aqueous solution containing the active substance is used as the inner aqueous phase; soybean oil is added to polyglycerol ricinoleate, and phosphate buffer is added to myofibrillar protein, and the two are mixed and homogenized to obtain an oil phase; b. The aqueous phase prepared in step a is mixed with the oil phase and homogenized to obtain a W / O emulsion; c. dissolving gum arabic and xanthan gum in water to obtain an external aqueous phase; d. The W / O emulsion prepared in step b is mixed with the external water phase prepared in step c to obtain a stable W / O / W double emulsion.

2. The method for preparing the W / O / W double emulsion based on co-stabilization of myofibrillar protein and polyglycerol ricinoleate according to claim 1, characterized in that: The active substance in step a is a water-soluble biologically active ingredient.

3. The method for preparing the W / O / W double emulsion based on co-stabilization of myofibrillar protein and polyglycerol ricinoleate according to claim 1, characterized in that: The active substance in step a is selected from one or more of beetroot red, amaranth, monascus red, sorghum red and rose red.

4. The method for preparing the W / O / W double emulsion based on co-stabilization of myofibrillar protein / polyglycerol ricinoleate according to claim 1, characterized in that: The mass ratio concentration of the polyglycerol ricinoleate in soybean oil in step a is 2-6% (w / w), and the mass concentration of the myofibrillar protein in the phosphate buffer in step a is 5-15 mg / mL; the volume ratio of soybean oil to the phosphate buffer containing myofibrillar protein is 1:4-3:7; preferably, the phosphate buffer is 20 mmol / L K2HPO4 / KH2PO4, 0.6 mol / L NaCl, and pH 7.

0.

5. The method for preparing the W / O / W double emulsion based on co-stabilization of myofibrillar protein / polyglycerol ricinoleate according to claim 1, characterized in that: The homogenizing conditions are 6000-8000 rpm, and the homogenizing time is 1-3 minutes.

6. The method for preparing the W / O / W double emulsion based on co-stabilization of myofibrillar protein / polyglycerol ricinoleate according to claim 1, characterized in that: The homogenization conditions described in step b are 8000-15000 rpm, the homogenization time is 2-4 min, and the volume ratio of the water phase to the oil phase during homogenization is 1:4-3:

5.

7. The method for preparing the W / O / W double emulsion based on co-stabilization of myofibrillar protein / polyglycerol ricinoleate according to claim 1, characterized in that: In step c, the mass ratio concentration of gum arabic and xanthan gum in water is 1-3% (w / v) and 0.2-0.4% (w / v), respectively, and the dissolution condition is 45-60° C., and stirring is performed until dissolved; preferably, the stirring time is 90-150 min.

8. The method for preparing the W / O / W double emulsion based on co-stabilization of myofibrillar protein / polyglycerol ricinoleate according to claim 1, characterized in that: The homogenization conditions described in step d are 8000-10000 rpm, the homogenization time is 1-3 min, and the volume ratio of the W / O emulsion to the external aqueous phase is 1:4-3:

5.

9. A co-stabilized W / O / W double emulsion prepared by the preparation method described in any one of claims 1 to 11.

10. Use of the W / O / W double emulsion according to claim 9 in the preparation of emulsified meat products, characterized in that: The W / O / W double emulsion is a combination of one or more of an emulsifier, a color protectant, a preservative, and an antioxidant.

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