Double-gel bead based on protein and polysaccharide gel as well as preparation method and application of double-gel bead

Abstract

The invention discloses a double-gel bead based on protein and polysaccharide gel as well as a preparation method and application of the double-gel bead, and belongs to the technical field of biological materials. The sphericity degree of the double-gel bead is not lower than 0.9, and the double-gel bead is composed of an oil phase containing an oil gel and a water phase containing a hydrogel and an emulsifier. The preparation method is simple and efficient, the hardness and elasticity of the double-gel bead are adjustable, most protein and polysaccharide gels with thermal induction gelling property can be used as preparation raw materials, and the selection range of hydrogel raw materials in the double-gel bead is widened. In the field of food, the double-gel bead can be used for packaging and delivering bioactive substances, prolonging the shelf life of functional components and improving the texture and taste of food, and can be directly added or applied to a food system in the form of an edible packaging material.

Description

Technical Field

[0001] The invention belongs to the technical field of biomaterials, and in particular relates to double gel beads based on protein and polysaccharide gelling agents, and a preparation method and application thereof. Background Art

[0002] Gel beads are spherical or nearly spherical colloidal particles with a diameter of more than 1000 μm and a three-dimensional gel network structure. According to the different core structures, gel beads can be divided into solid gel beads, liquid gel beads and emulsion gel beads. In the field of food, gel beads are usually prepared by dropping gel liquid into a metal ion bath using a hydrogel with ion cross-linking properties as a raw material. At present, gel beads are mainly used for the embedding of edible materials and water-soluble bioactive substances, and rarely involve the encapsulation of fat-soluble functional components. Although the Chinese invention patent CN 114230815A uses pectin as the main gelling agent to prepare emulsion gel beads for embedding fat-soluble flavonoids, the preparation process is complicated and the cycle is long. The gel beads require a solidification time of 4-12 hours, and the liquid oil phase in the emulsion gel beads has poor storage stability and is prone to leakage.

[0003] Double gel is a uniform semisolid dispersion system, which is mainly prepared by high-speed shear mixing of alginate and other gelling agents at a certain temperature. Hydrogel and oil gel. Double gel has good stable physical properties, which makes up for the deficiency that traditional gel beads cannot deliver hydrophilic and lipophilic substances at the same time. In the biomedical field, Mousavi et al. (Seyedeh Neda Mousavi et al., Synthesis of a green bigel using cottonseed oil / cannabis oil / alginate / ferula gum for quercetin release: Synergistic effects for treating infertility in rats [J]. International Journal of Biological Macromolecules, 2021, 177: 157-165) used cottonseed oil, hemp oil, alginate and asafetida gum as raw materials to prepare double gel beads encapsulating quercetin, realizing the sustained release of drug ingredients in the human body to prevent non-alcoholic fatty liver disease. Although the double gel beads prepared by it have a nearly spherical structure, there are pores on the surface, and the overall structural stability is poor. In the field of food, Chinese invention patent CN 115088830A constructed a microgel bead based on alginate that simultaneously loads multipolar functional factors, and explored the differences in the properties of double gel beads with different two-phase ratios. With the increase in the proportion of the oil phase, the loading rate of the oil phase functional factors in the double gel beads increased, but the hardness gradually decreased. In summary, the current double gel beads still rely on sodium alginate as the main raw material for preparation, and there are problems such as high porosity, insufficient structural strength, and difficult to control physical stability.

[0004] Heat-induced gelation is a common and important gelation method. The gelling agent molecules absorb heat energy and unfold or dissociate, then aggregate through spiral association, and transform into a solid gel structure after cooling. Polysaccharide and protein gelling agents such as carrageenan, gelatin and whey protein isolate can form gels in this way. More and more studies have shown that such heat-induced gelling agents have better physicochemical properties and application value than alginate gelling agents. Chinese invention patent CN115005445A uses whey protein isolate as a gelling agent to fix soybean oil bodies, and prepares a gel with good mechanical properties, high nutritional value and safety, and the potential to simulate fat. However, the above patent can only prepare block-shaped double gels, and how to use such heat-induced gelling agents as raw materials to prepare double gel beads with high sphericity is still blank in the general process design of related fields. Summary of the invention

[0005] In view of the deficiencies involved in the above-mentioned background technology, the technical problems to be solved by the present invention are, first, to solve the problems of complex preparation process and long preparation cycle of double gel beads, and to provide a preparation method of double gel beads with simple process steps and rapid solidification of dual-phase components (no more than 10 minutes); second, to provide double gel beads with high sphericity and excellent mechanical properties, so that the physical stability can be effectively adjusted with the change of components, and the shelf life of the encapsulated components can be effectively extended; third, to provide a double gel bead based on heat-induced gelation, expand the selection range of preparation raw materials, and realize broad application in the field of food ingredients.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing double gel beads, comprising the following steps:

[0008] (1) preparing the aqueous phase: dispersing the hydrogel and the emulsifier in water, mixing them evenly, and keeping the temperature constant for later use;

[0009] (2) preparing the oil phase: dispersing the oil gel in the edible oil, mixing evenly, and keeping the temperature constant for later use;

[0010] (3) slowly adding the oil phase prepared in step (2) to the water phase prepared in step (1) at a mass ratio of 5:5 to 1:9, and then emulsifying to obtain a uniform oil-in-water type double gel solution, and keeping the temperature constant for later use;

[0011] (4) dropping the bigel solution obtained in step (3) into a constant temperature bath at a constant temperature of 60 to 80° C. at a rate of 0.1 to 0.3 mL / min to obtain solid bigel beads;

[0012] The hydrogel is one or more of gelatin, whey protein isolate, carrageenan, gellan gum, and potato starch; the emulsifier is one or more of Tween 20, Tween 40, Tween 60, and lecithin;

[0013] The oil gel is one or more of beeswax, rice bran wax, glyceryl monostearate, and ethyl cellulose; the edible oil is one or more of walnut oil, corn oil, rapeseed oil, and soybean oil.

[0014] Furthermore, in the step (1), the mass percentage of the hydrogel in the aqueous phase is 10-20%, and the mass percentage of the emulsifier is 2-8%; and the constant temperature during standby is 55-70°C.

[0015] Furthermore, the mass percentage of the oil gel in the oil phase of step (2) is 10-15%, and the constant temperature during standby is 55-70°C.

[0016] Furthermore, in step (3), the mass ratio of the oil phase to the water phase is 4:6 to 2:8.

[0017] Furthermore, the emulsification process includes shearing and ultrasonic treatment; the shearing speed is 5000-10000 r / min, and the shearing time is 5-10 min; the ultrasonic power is 160-200 W, and the ultrasonic time is 3-8 min.

[0018] Furthermore, the shearing speed is 6000-8000 r / min, and the shearing time is 3-8 min.

[0019] Furthermore, the constant temperature during standby in step (3) is 55-70°C.

[0020] Furthermore, the device for dripping the double gel liquid in step (4) is a device capable of dripping liquid at a constant temperature and speed, and the diameter of the double gel liquid dripping pinhole is 0.6-1.8 mm.

[0021] Furthermore, in the step (4), the temperature for dropping the double gel solution is 60-70° C., the dropping rate is 0.1-0.2 mL / min, and the dropping height is 5-10 mm.

[0022] Furthermore, the constant temperature bath liquid includes one or more of edible alcohol and liquid nitrogen; the constant temperature of the edible alcohol is -5 to 0°C; and the water bath time is 2 to 8 minutes.

[0023] Furthermore, the diameter of the double gel beads prepared in step (4) is 1-5 mm; the sphericity of the double gel beads prepared is 0.90-1; and the hardness of the double gel beads prepared is 0.1-10N.

[0024] In step (4), a heat-induced gelation method is adopted, which utilizes the principle that a low molecular weight hydrogel will self-assemble into a hydrated fiber network after being dissolved at high temperature and then cooled, and that an oil gel will self-assemble into crystals after being dissolved at high temperature and then cooled. The double gel liquid is dripped into the bath liquid through a dripping device, and the low temperature is used to promote the transformation of the double gel liquid from liquid to solid within 1 second, thereby effectively avoiding the loss of the oil phase component in the bath liquid.

[0025] The present invention also provides an application of the double gel beads in the food field, wherein the application includes using the double gel beads as a material for encapsulating and delivering bioactive substances, or as an edible packaging material.

[0026] Furthermore, the food includes one or more of ice cream, western-style cakes, jelly, puffed food, and gum-based candy.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention has a variety of raw material options, simple and efficient process steps, small errors in the same batch of products, and can meet the requirements of automated production.

[0029] (2) During the preparation process, the physical properties of the double gel beads, such as sphericity, particle size, and hardness, can be adjusted by regulating the dropping height, bath temperature, and oil-water phase content, so as to formulate the double gel beads according to the actual application scenario.

[0030] (3) The prepared double gel beads contain two components of different polarities, namely, the oil phase and the water phase, which realizes its comprehensive loading capacity in the food field. The solidification of the oil phase component can effectively enhance the mechanical strength and delay the loss and oxidation rate of the oil phase. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The appearance of the gel beads of Example 1 and Comparative Example 1 (from left to right in the figure are the gel beads of Comparative Example 1, the gel beads obtained with 6% gelatin, the gel beads obtained with 8% gelatin, and the gel beads obtained with 10% gelatin);

[0032] Figure 2 This is an appearance diagram of Example 5 (from left to right in the figure are gel beads with oil-water phase mass ratios of 4:6, 3:7 and 2:8);

[0033] Figure 3 The texture characteristics analysis diagram of the gel beads of Example 1 and Comparative Example 1;

[0034] Figure 4 This is a diagram of the oil oxidation stability of the gel beads of Example 1 and Comparative Example 1;

[0035] Figure 5 This is a schematic diagram of some application scenarios of Example 1; DETAILED DESCRIPTION

[0036] In order to better illustrate the present invention, the following embodiments are listed. Obviously, the described embodiments are only a part of the present invention, not all embodiments. Based on the embodiments in the present invention, other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0037] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0038] Example 1

[0039] (1) Preparation of the aqueous phase: Carrageenan (accounting for 0.5% of the aqueous phase, w / w), gelatin (set to account for 6%, 8%, and 10% of the aqueous phase, w / w), and emulsifier Tween 20 (accounting for 4.0% of the aqueous phase, w / w) were dispersed in deionized water, stirred at 85°C until completely dissolved, and finally placed in a constant temperature water bath at 65°C for equilibration for more than 30 min for use.

[0040] (2) Preparation of the oil phase: beeswax (15.0% of the oil phase, w / w) was dispersed in walnut oil, stirred at 85°C until completely dissolved, and finally placed in a constant temperature water bath at 65°C for equilibration for more than 30 minutes for use.

[0041] (3) At 65° C., the oil gel solution obtained in step (2) was transferred to the hydrogel solution obtained in step (1), wherein the mass ratio of the oil phase to the water phase was 4:6, and then sheared at 7000 r / min for 5 min using a shearing machine, and the sheared double gel solution was ultrasonicated at a power of 180 W for 5 min, and finally placed in a constant temperature water bath at 65° C. for equilibration for more than 30 min for use.

[0042] (4) The double gel solution prepared in step (3) is dripped into edible alcohol (alcohol content ≥ 95% vol) through a peristaltic pump through a syringe needle with an inner diameter of 1.6 mm at a dripping speed of 0.15 mL / min. During this period, the infusion hose is wrapped with a glass fiber temperature control belt to ensure that the double gel solution delivery temperature is constant at 65°C. The edible alcohol is placed in a semiconductor refrigerator and the temperature is constant at -4°C. The double gel solution is dripped at a height of 1.00 cm, and double gel beads are formed in a water bath for 5 minutes. Subsequently, the double gel beads are filtered and washed with deionized water several times to remove excess edible alcohol on the surface (alcohol residue ≤ 0.02%). The residual moisture on the surface of the double gel beads is wiped with a paper towel and stored in a refrigerator at 4°C.

[0043] Example 2

[0044] (1) Preparation of the aqueous phase: Carrageenan (3.0% of the aqueous phase, w / w), potato starch (7% of the aqueous phase, w / w) and emulsifier Tween 20 (4.0% of the aqueous phase, w / w) were dispersed in deionized water, stirred at 85°C until completely dissolved, and finally placed in a constant temperature water bath at 65°C for equilibration for more than 30 min for use.

[0045] (2) Preparation of the oil phase: beeswax (15.0% of the oil phase, w / w) was dispersed in corn oil, stirred at 85°C until completely dissolved, and finally placed in a 65°C constant temperature water bath for equilibration for more than 30 min for use.

[0046] (3) At 65° C., the oil gel solution obtained in step (2) was transferred to the hydrogel solution obtained in step (1), wherein the mass ratio of the oil phase to the water phase was 4:6, and then sheared at 7000 r / min for 5 min using a shearing machine, and the sheared double gel solution was ultrasonicated at a power of 180 W for 5 min, and finally placed in a constant temperature water bath at 65° C. for equilibration for more than 30 min for use.

[0047] (4) The double gel solution prepared in step (3) is dripped into edible alcohol (alcohol content ≥ 95% vol) through a peristaltic pump through a syringe needle with an inner diameter of 1.6 mm at a dripping speed of 0.15 mL / min. During this period, the infusion hose is wrapped with a glass fiber temperature control belt to ensure that the double gel solution delivery temperature is constant at 65°C. The edible alcohol is placed in a semiconductor refrigerator and the temperature is constant at -4°C. The double gel solution is dripped at a height of 1.00 cm, and double gel beads are formed in a water bath for 5 minutes. Subsequently, the double gel beads are filtered and washed with deionized water several times to remove excess edible alcohol on the surface (alcohol residue ≤ 0.02%). The residual moisture on the surface of the double gel beads is wiped with a paper towel and stored in a refrigerator at 4°C.

[0048] Example 3

[0049] (1) Preparation of the aqueous phase: Carrageenan (accounting for 0.5% of the aqueous phase, w / w), whey protein isolate (accounting for 10% of the aqueous phase, w / w) and emulsifier Tween 20 (accounting for 4.0% of the aqueous phase, w / w) were dispersed in deionized water, stirred at 85°C until completely dissolved, and finally placed in a constant temperature water bath at 65°C for equilibration for more than 30 minutes for use.

[0050] (2) Preparation of the oil phase: Disperse monostearate (10.0% of the oil phase, w / w) in rapeseed oil, stir at 85°C until completely dissolved, and finally place in a 65°C constant temperature water bath for equilibration for more than 30 minutes for use.

[0051] (3) At 65° C., the oil gel solution obtained in step (2) was transferred to the hydrogel solution obtained in step (1), wherein the mass ratio of the oil phase to the water phase was 4:6, and then sheared at 7000 r / min for 5 min using a shearing machine, and the sheared double gel solution was ultrasonicated at a power of 180 W for 5 min, and finally placed in a constant temperature water bath at 65° C. for equilibration for more than 30 min for use.

[0052] (4) The double gel solution prepared in step (3) is dripped into edible alcohol (alcohol content ≥ 95% vol) through a peristaltic pump through a syringe needle with an inner diameter of 1.6 mm at a dripping speed of 0.15 mL / min. During this period, the infusion hose is wrapped with a glass fiber temperature control belt to ensure that the double gel solution delivery temperature is constant at 65°C. The edible alcohol is placed in a semiconductor refrigerator and the temperature is constant at 0°C. The double gel solution is dripped at a height of 1.00 cm, and double gel beads are formed in a water bath for 5 minutes. Subsequently, the double gel beads are filtered and washed with deionized water several times to remove excess edible alcohol on the surface (alcohol residue ≤ 0.02%). The residual moisture on the surface of the double gel beads is wiped with a paper towel and stored in a refrigerator at 4°C.

[0053] Example 4

[0054] (1) Preparation of aqueous phase: Potato starch (7% of the aqueous phase, w / w), whey protein isolate (10% of the aqueous phase, w / w) and emulsifier Tween 20 (4.0% of the aqueous phase, w / w) were dispersed in deionized water, stirred at 85°C until completely dissolved, and finally placed in a constant temperature water bath at 65°C for equilibration for more than 30 min for use.

[0055] (2) Preparation of the oil phase: Disperse monostearate (10.0% of the oil phase, w / w) in peanut oil, stir at 85°C until completely dissolved, and finally place in a 65°C constant temperature water bath for equilibration for more than 30 min for use.

[0056] (3) At 65° C., the oil gel solution obtained in step (2) was transferred to the hydrogel solution obtained in step (1), wherein the mass ratio of the oil phase to the water phase was 4:6, and then sheared at 7000 r / min for 5 min using a shearing machine, and the sheared double gel solution was ultrasonicated at a power of 180 W for 5 min, and finally placed in a constant temperature water bath at 65° C. for equilibration for more than 30 min for use.

[0057] (4) The double gel solution prepared in step (3) is dripped into edible alcohol (alcohol content ≥ 95% vol) through a peristaltic pump through a syringe needle with an inner diameter of 1.6 mm at a dripping speed of 0.15 mL / min. During this period, the infusion hose is wrapped with a glass fiber temperature control belt to ensure that the double gel solution delivery temperature is constant at 65°C. The edible alcohol is placed in a semiconductor refrigerator and the temperature is constant at 0°C. The double gel solution is dripped at a height of 0.80 cm, and double gel beads are formed in a water bath for 5 minutes. Subsequently, the double gel beads are filtered and washed with deionized water several times to remove excess edible alcohol on the surface (alcohol residue ≤ 0.02%). The residual moisture on the surface of the double gel beads is wiped with a paper towel and stored in a refrigerator at 4°C.

[0058] Example 5

[0059] (1) Preparation of aqueous phase: Disperse carrageenan (accounting for 0.5% of the aqueous phase, w / w), gelatin (accounting for 10% of the aqueous phase, w / w) and emulsifier Tween 20 (accounting for 4.0% of the aqueous phase, w / w) in deionized water, stir at 85°C until completely dissolved, and finally place in a constant temperature water bath at 65°C for equilibration for more than 30 min for use.

[0060] (2) Preparation of the oil phase: beeswax (15.0% of the oil phase, w / w) was dispersed in walnut oil, stirred at 85°C until completely dissolved, and finally placed in a constant temperature water bath at 65°C for equilibration for more than 30 minutes for use.

[0061] (3) At 65°C, the oil gel solution obtained in step (2) was transferred to the hydrogel solution obtained in step (1), and the mass ratios of the oil phase and the water phase were set to 4:6, 3:7 and 2:8, followed by shearing with a shearing machine at 7000 r / min for 5 min, ultrasonicating the mixed double gel solution at a power of 180 W for 5 min, and finally placing it in a constant temperature water bath at 65°C for equilibration for more than 30 min for use.

[0062] (4) The double gel solution prepared in step (3) is dripped into edible alcohol (alcohol content ≥ 95% vol) through a peristaltic pump through a syringe needle with an inner diameter of 1.6 mm at a dripping speed of 0.15 mL / min. During this period, the infusion hose is wrapped with a glass fiber temperature control belt to ensure that the double gel solution delivery temperature is constant at 65°C. The edible alcohol is placed in a semiconductor refrigerator and the temperature is constant at -4°C. The double gel solution is dripped at a height of 1.00 cm, and double gel beads are formed in a water bath for 5 minutes. Subsequently, the double gel beads are filtered and washed with deionized water several times to remove excess edible alcohol on the surface (alcohol residue ≤ 0.02%). The residual moisture on the surface of the double gel beads is wiped with a paper towel and stored in a refrigerator at 4°C.

[0063] Comparative Example 1

[0064] (1) Preparation of aqueous phase: Disperse carrageenan (accounting for 0.5% of the aqueous phase, w / w), gelatin (accounting for 10% of the aqueous phase, w / w) and emulsifier Tween 20 (accounting for 4.0% of the aqueous phase, w / w) in deionized water, stir at 85°C until completely dissolved, and finally place in a constant temperature water bath at 65°C for equilibration for more than 30 min for use.

[0065] (2) Preparation of the oil phase: Place the walnut oil in a 65°C constant temperature water bath and equilibrate for more than 30 minutes.

[0066] (3) At 65° C., the oil phase obtained in step (2) was transferred to the hydrogel solution obtained in step (1), wherein the mass ratio of the oil phase to the water phase was 4:6, and then sheared at 7000 r / min for 5 min using a shearing machine, and the sheared double gel solution was ultrasonicated at a power of 180 W for 5 min, and finally placed in a constant temperature water bath at 65° C. for equilibration for more than 30 min for use.

[0067] (4) The emulsion gel prepared in step (3) is dripped into edible alcohol (alcohol content ≥ 95% vol) through a peristaltic pump and a syringe needle with an inner diameter of 1.6 mm at a dripping speed of 0.15 mL / min. During this period, the infusion hose is wrapped with a glass fiber temperature control belt to ensure that the emulsion gel delivery temperature is constant at 65°C. The edible alcohol is placed in a semiconductor refrigerator and the temperature is constant at 0°C. The double gel liquid is dripped at a height of 1.00 cm, and the water bath is placed for 5 minutes to form emulsion gel beads, which are then filtered and washed with deionized water several times to remove excess edible alcohol on the surface (alcohol residue ≤ 0.02%). The residual moisture on the surface of the emulsion gel beads is wiped with a paper towel and stored in a refrigerator at 4°C.

[0068] Test Example 1 Particle Size and Sphericity Analysis

[0069] The particle size and sphericity of the samples were analyzed and statistically analyzed using the software imageJ. The calculation formula for sphericity is as follows (1):

[0070]

[0071] Where D L and D S are the major axis and minor axis diameters of the double gel beads, respectively. In Example 1 and Comparative Example 1, 100 samples were selected for statistical calculation in each group of samples, as shown in Table 1 below; Based on the optimization of raw materials, Example 5 further verifies the influence of the oil-water phase mass ratio on the particle size and sphericity of the gel beads, and the measurement results are shown in Table 2 below.

[0072] Table 1 Particle size and sphericity of gel beads in Example 1 and Comparative Example 1

[0073]

[0074] Note: Different letters in the same column indicate significant differences (P<0.05).

[0075] Table 2 Particle size and sphericity of gel beads in Example 5

[0076]

[0077] Note: Different letters in the same column indicate significant differences (P<0.05).

[0078] As shown in Table 1, with the increase of gelatin content, the particle size of the double gel beads first increases and then decreases. When the gelatin content is 8%, the particle size of the double gel beads reaches the maximum, which is 3.02±0.17cm, while the sphericity is lower when the gelatin content is 6%. The sphericity difference of the double gel beads in each group did not change significantly, and the sphericity values ​​were all around 0.94. The experimental results show that the double gel beads can be effectively prepared under different gelatin concentrations, with good sphericity and a particle size between 2.5-3.0cm.

[0079] It can be seen from Table 2 that after increasing the oil phase ratio, the particle size and sphericity of the double gel beads increased.

[0080] Test Example 2 Texture Analysis

[0081] The mechanical properties of the gel were evaluated by uniaxial compression test using a CT3 texture analyzer. The gel was tested at room temperature using a cylindrical plunger probe with a diameter of 12 mm at a test rate of 1 mm / s, a trigger point load of 0.05 N, and a deformation amount set to 50%, and the hardness of the sample was recorded. The Young's modulus was determined based on the Hertz theory, and the calculation formula is as follows (2):

[0082]

[0083] Where R0 is the radius of the double gel bead, E is Young's modulus, H is the displacement, ν is Poisson's ratio, and F is the applied force. First, the compression force (F) and the displacement (H) are 3 / 2 Plot. Poisson's ratio ν is assumed to be 0.5. Then, FH 3 / 2 The slope of the graph determines the Young's modulus of the gel beads.

[0084] Figure 3 The texture characteristics analysis diagram of the gel beads of Example 1 and Comparative Example 1. It can be seen from the experimental results that with the increase of gelatin content, the hardness and Young's modulus of the double gel beads increased significantly (P<0.05), and the double gel beads showed higher hardness and Young's modulus, which can be applied to a wider range of food application scenarios.

[0085] Test Example 3 Analysis of Oxidative Stability of Oils and Fats

[0086] Take the same mass of Example 1 and Comparative Example 1 gel beads, store the samples in the dark at 4°C for 12 days, and measure the PV value of the samples every 3 days. The measurement method is as follows: First, take a certain amount of sample and dissolve it in 5mL of chloroform / methanol (7:3, v / v) mixed solution, add 25μL of potassium thiocyanate solution and 25μL of ferrous chloride solution, and use UV1800 ultraviolet-visible spectrophotometer to measure its absorbance at 500nm, and perform quantitative calculation with the aid of the standard curve. The calculation formula is as follows (3):

[0087]

[0088] Where A represents the content of trivalent iron ions in the chloroform / methanol (7:3 v / v) mixture, "55.84" is the relative atomic weight of iron, "2" is the calibration constant, and m is the mass of the sample.

[0089] Figure 4 The diagram is a diagram of the oil oxidation stability of the gel beads of Example 1 and Comparative Example 1. As can be seen from the figure, after 12 days of oxidation experiment, with the increase of gelatin content, the oil oxidation of the double gel beads in the same time period gradually decreased. Compared with the emulsion gel beads, this experimental method can effectively slow down the oxidation rate of oil during storage.

[0090] Figure 5 This is a schematic diagram of some application scenarios of Example 1. In various food systems, such as beverages and cakes, the double gel beads show high adaptability and can effectively improve the sensory experience of food.

[0091] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing double gel beads, characterized in that: The following steps are involved: (1) preparing the aqueous phase: dispersing the hydrogel and the emulsifier in water, mixing them evenly, and keeping the temperature constant for later use; (2) preparing the oil phase: dispersing the oil gel in the edible oil, mixing evenly, and keeping the temperature constant for later use; (3) slowly adding the oil phase prepared in step (2) to the water phase prepared in step (1) at a mass ratio of 5:5 to 1:9, and then emulsifying to obtain a uniform double gel solution, which is kept at a constant temperature for later use; (4) dropping the bigel solution obtained in step (3) into a constant temperature bath at a constant temperature of 60 to 80° C. at a rate of 0.1 to 0.3 mL / min to obtain solid bigel beads; The hydrogel is one or more of gelatin, whey protein isolate, carrageenan, gellan gum, and potato starch; the emulsifier is one or more of Tween 20, Tween 40, Tween 60, and lecithin; The oil gel is one or more of beeswax, rice bran wax, glyceryl monostearate, and ethyl cellulose; the edible oil is one or more of walnut oil, corn oil, rapeseed oil, and soybean oil.

2. The preparation method according to claim 1, characterized in that: In the step (1), the mass percentage of the hydrogel agent in the aqueous phase is 10-20%, and the mass percentage of the emulsifier is 2-8%.

3. The preparation method according to claim 1, characterized in that: The mass percentage of the oil gel in the oil phase of step (2) is 10-15%.

4. The preparation method according to claim 1, characterized in that: In the step (3), the mass ratio of the oil phase to the water phase is 4:6 to 2:

8.

5. The preparation method according to claim 4, characterized in that: The emulsification process includes shearing and ultrasonic treatment; the shearing speed is 5000-10000 r / min, and the shearing time is 5-10 min; the ultrasonic power is 160-200 W, and the ultrasonic time is 3-8 min.

6. The preparation method according to claim 5, characterized in that: The shearing speed is 6000-8000 r / min, and the shearing time is 3-8 min.

7. The preparation method according to claim 1, characterized in that: In the step (4), the double gel liquid is added at a temperature of 60 to 70° C. and a dropping rate of 0.1 to 0.2 mL / min; and the dropping height is 5 to 10 mm.

8. The preparation method according to claim 7, characterized in that: The constant temperature bath liquid comprises one or more of edible alcohol and liquid nitrogen; the constant temperature of the edible alcohol is -5 to 0°C; and the water bath time is 2 to 8 minutes.

9. Application of the double gel beads according to any one of claims 1 to 8 in the food field, characterized in that: The applications include using the dual gel beads as materials for encapsulating and delivering bioactive substances, or as edible packaging materials.

10. The use according to claim 9, wherein the food comprises one or more of ice cream, western-style cakes, jelly, puffed food, and gum-based candy.

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