Preparation method of carotene emulsion gel with high freeze-thaw stability

Abstract

The invention discloses a preparation method of carotene emulsion gel with high freeze-thaw stability, beta-carotene and coconut oil are mixed to form an oil phase, an aqueous solution of brown algae cellulose is used as a water phase, the brown algae cellulose not only can provide steric hindrance effect, but also can have synergistic effect with the active ingredient beta-carotene, so that the effect of improving the freeze-thaw stability of the carotene emulsion gel is achieved. According to the present invention, the oil phase and the water phase are combined to form the stable honeycomb structure so as to further fix the connection of the oil phase and the water phase, such that the gel structure of the emulsion gel is significantly improved, the beta-carotene can be fixed, and the encapsulation efficiency of the beta-carotene can be significantly improved; meanwhile, the freeze-thaw stability of the freeze-thaw gel is also remarkably enhanced, so that the freeze-thaw gel can still keep a stable gel state after multiple freeze-thaw cycles. The viscosity and elastic characteristics of the emulsion gel can be accurately regulated and controlled by controlling the concentration of the water phase, the concentration of the oil phase and the mass ratio of the water phase to the oil phase, so that the emulsion gel with various structures and functions is designed, and different application requirements are met.

Description

Technical Field

[0001] The invention belongs to the technical field of food gels, and particularly relates to a method for preparing a carotene emulsion gel with high freeze-thaw stability. Background Art

[0002] Emulsion gels are semisolid materials with a gel-like network structure, filled with emulsion droplets. They combine the properties of both emulsions and gels, demonstrating significant advantages as fat substitutes and in improving the stability of bioactive factors. Emulsion gels can be categorized as protein emulsion gels, polysaccharide emulsion gels, and composite emulsion gels, depending on the gel matrix. However, their structural and functional properties primarily depend on the interaction between the gel matrix and the filler particles.

[0003] Existing methods for preparing emulsion gels typically involve two steps: first, preparing an emulsion through emulsification, and second, gelling the emulsion's continuous phase through a specific induction method. Common induction methods include heat, acid, salt, enzyme, and chemical crosslinker induction. These methods not only involve high amounts of exogenous additives and a complex preparation process, but also suffer from poor freeze-thaw stability and difficulty maintaining structural integrity after long-term refrigeration or freezing, limiting their application in industries such as food, medicine, and cosmetics. Summary of the Invention

[0004] The present invention aims to solve the above technical problems existing in the prior art and provides a method for preparing a carotene emulsion gel with high freeze-thaw stability.

[0005] The technical solution of the present invention is: a method for preparing a carotene emulsion gel with high freeze-thaw stability, which is carried out according to the following steps: Step 1. Prepare the oil phase: dissolve β-carotene in coconut oil to a final concentration of 124-136 mmol / L; Step 2. Prepare the aqueous phase: Dissolve algal cellulose in water to a final concentration of 24-26 mg / mL; Step 3. Prepare the emulsion gel: Mix the oil phase and the water phase in a mass ratio of 20-40:100 and homogenize at high speed, then let it stand at 3-5°C for 28-32 minutes.

[0006] Preferably, the speed of the high-speed homogenization in step 3 is 7000-8000 rpm, and the time is 28-32 seconds.

[0007] In the present invention, β-carotene is mixed with coconut oil to form an oil phase, and an aqueous solution of algal cellulose is used as the water phase. Algal cellulose can not only provide steric hindrance, but also synergistically act with the active ingredient β-carotene to form a stable "honeycomb" structure, further fixing the connection between the oil phase and the water phase, significantly improving the gel structure of the emulsion gel, fixing β-carotene, and significantly increasing the encapsulation rate of β-carotene. At the same time, the present invention also significantly enhances its freeze-thaw stability, enabling it to maintain a stable gel state after multiple freeze-thaw cycles. The present invention can precisely control the viscosity and elasticity characteristics of the emulsion gel by controlling the water phase concentration, oil phase concentration, and mass ratio between the water phase and the oil phase, thereby designing emulsion gels with various structures and functions to meet different application requirements. The present invention does not require external additives, simplifies the preparation process of the emulsion gel, and reduces the preparation cost. Description of the Drawings

[0008] Figure 1 It is a comparison chart of the emulsification index of the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3 of the present invention.

[0009] Figure 2 It is a comparison chart of the freeze-thaw stability of the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3 of the present invention.

[0010] Figure 3 It is a chart of the emulsification index of the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3 of the present invention when stored at 4°C for 14 days and 28 days respectively.

[0011] Figure 4 It is a chart of the emulsification index of the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3 of the present invention when stored at 25°C for 14 days and 28 days respectively.

[0012] Figure 5 It is a chart of the β-carotene encapsulation rate in the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3 of the present invention.

[0013] Figure 6 It is a chart of the β-carotene encapsulation rate in the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3 of the present invention after storage at 4°C and 25°C for 28 days respectively. Detailed Description of the Invention Example 1

[0014] A preparation method of a carotene emulsion gel with high freeze-thaw stability is carried out according to the following steps: Step 1. Prepare the oil phase: Take β-carotene and stir it with a magnetic stirrer at room temperature until β-carotene is completely dissolved in vegetable oil, and the final concentration of β-carotene is 130 mmol / L; Step 2. Prepare the aqueous phase: Dissolve alginate cellulose in water at room temperature, with the final concentration of the alginate cellulose being 25 mg / mL; Step 3. Prepare the emulsion gel: Mix the oil phase and the aqueous phase at a mass ratio of 20:100 and homogenize at 7000 rpm for 28 seconds, and then leave it to stand at 4°C for 30 minutes.

[0015] Example 2: A method for preparing a carotene emulsion gel with high freeze-thaw stability is carried out according to the following steps: Step 1. Prepare the oil phase: Take β-carotene and stir it with a magnetic stirrer at room temperature until β-carotene is completely dissolved in vegetable oil, with the final concentration of the β-carotene being 130 mmol / L; Step 2. Prepare the aqueous phase: Dissolve alginate cellulose in water at room temperature, with the final concentration of the alginate cellulose being 25 mg / mL; Step 3. Prepare the emulsion gel: Mix the oil phase and the aqueous phase at a mass ratio of 30:100 and homogenize at 7500 rpm for 30 seconds, and then leave it to stand at 4°C for 30 minutes.

[0016] Example 3: A method for preparing a carotene emulsion gel with high freeze-thaw stability is carried out according to the following steps: Step 1. Prepare the oil phase: Take β-carotene and stir it with a magnetic stirrer at room temperature until β-carotene is completely dissolved in vegetable oil, with the final concentration of the β-carotene being 130 mmol / L; Step 2. Prepare the aqueous phase: Dissolve alginate cellulose in water at room temperature, with the final concentration of the alginate cellulose being 25 mg / mL; Step 3. Prepare the emulsion gel: Mix the oil phase and the aqueous phase at a mass ratio of 40:100 and homogenize at 8000 rpm for 32 seconds, and then leave it to stand at 4°C for 30 minutes.

[0017] Comparative Examples 1-3: The basic operation steps of Comparative Examples 1-3 are respectively the same as those of Examples 1-3, and the difference is that the oil phase is 100% coconut oil.

[0018] Experiment: 1. Conduct an emulsification index comparison experiment on the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3 Taking Examples 1 - 3 as the experimental groups and Comparative Examples 1 - 3 as the control groups, 10 g of the emulsion gels obtained from Examples 1 - 3 and Comparative Examples 1 - 3 were respectively placed in 15 - mL centrifuge tubes, centrifuged at a speed of 4000 rpm for 10 min under the condition of a temperature of 20°C, and the emulsification indices of their respective samples were detected. The results are as Figure 1 shown. Figure 1 In it, E20, E30, and E40 are respectively the emulsification indices of the emulsion gels obtained from Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3. It can be seen from Figure 1 it that the emulsification indices of the experimental groups are all higher than those of the control groups.

[0019] 2. Freeze - thaw stability experiment of the emulsion gels obtained from Examples 1 - 3 and Comparative Examples 1 - 3 Taking Examples 1 - 3 as the experimental groups and Comparative Examples 1 - 3 as the control groups, the emulsion gels obtained from Examples 1 - 3 and Comparative Examples 1 - 3 were respectively first placed in an environment of - 20°C and frozen for 12 h, and then taken out and placed at 25°C for 12 h.

[0020] Through direct visual observation, no obvious oil separation occurred, the appearance did not change significantly, and the gel properties were stable. 10 g was taken and placed in a 15 - mL centrifuge tube, and centrifuged at a speed of 4000 rpm for 10 min under the condition of a temperature of 20°C. The emulsification indices of their respective samples were detected. The results are as Figure 2 shown. Figure 2 In it, E20, E30, and E40 are respectively the emulsification indices of the emulsion gels obtained from Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3 after freeze - thaw. It can be seen from Figure 2 it that the emulsification indices of the experimental groups are all higher than those of the control groups.

[0021] 3. Comparative experiment on the emulsification indices of the emulsion gels obtained from Examples 1 - 3 and Comparative Examples 1 - 3 stored in a 4°C environment for 14 days and 28 days Taking Examples 1 - 3 as the experimental groups and Comparative Examples 1 - 3 as the control groups, the emulsion gels obtained from Examples 1 - 3 and Comparative Examples 1 - 3 were respectively sealed and placed in a 4°C environment and allowed to stand for 14 d and 28 d. Subsequently, 10 g was taken and placed in a 15 - mL centrifuge tube, and centrifuged at a speed of 4000 rpm for 10 min under the condition of a temperature of 20°C. The emulsification indices of their respective samples were detected. The results are as Figure 3 shown. Figure 3 In it, Figures A and B are respectively the graphs of the emulsification indices after standing in a ۴°C environment for 14 d and 28 d, where E20, E30, and E40 are respectively the emulsification indices of the emulsion gels obtained from Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example Figure 3It can be seen that the emulsion index of the experimental group is equivalent to or higher than that of the control group.

[0022] 4. Comparative experiment on the emulsion index of the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3 stored at 25 °C for 14 days and 28 days Taking Examples 1-3 as the experimental group and Comparative Examples 1-3 as the control group, respectively take the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3, seal them and place them in a 25 °C environment for 14 d and 28 d. Then take 10 g and put it into a 15 mL centrifuge tube, centrifuge at a speed of 4000 rpm and a temperature of 20 °C for 10 min, and detect the emulsion index of each sample. The results are as Figure 4 shown. Figure 4 Figures A and B in it are the emulsion index diagrams after standing at 25 °C for 14 d and 28 d respectively. Among them, E20, E30 and E40 are the emulsion indexes of the emulsion gels obtained in Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3 respectively. From Figure 4 it can be seen that the emulsion index of the experimental group is equivalent to or higher than that of the control group.

[0023] 5. Experiment on the encapsulation rate of β-carotene in the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3 Taking Examples 1-3 as the experimental group and Comparative Examples 1-3 as the control group, respectively take the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3, add n-hexane at a ratio of 1:1 (v / v), then centrifuge the mixture of the sample and n-hexane at 25 °C and 4000 rpm for 10 min, separate the upper extraction solution, and measure the encapsulation rate of β-carotene at a wavelength of 450 nm. The results are as Figure 5 shown. Figure 5 Among them, E20, E30 and E40 are the encapsulation rates of the emulsion gels obtained in Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3 respectively. From Figure 5 it can be seen that the encapsulation rate of the emulsion gels obtained in Examples 1-3 of the present invention for β-carotene is at least 80%.

[0024] 6. Experiment on the encapsulation rate of β-carotene in the emulsion gels obtained in Examples 1-3 and Comparative Examples 1-3 stored at 4 °C and 25 °C for 28 days Taking Examples 1-3 as the experimental group and Comparative Examples 1-3 as the control group, respectively take the emulsion gels obtained in Examples 1-3 and Comparative Examples The emulsion gels obtained in 1-3 were sealed and left to stand at 4 °C and 25 °C for 28 d. For each sample, n-hexane was added in a 1:1 (v / v) ratio. Subsequently, the mixture of the sample and n-hexane was centrifuged at 25 °C and 4000 rpm for 10 min to separate the upper extraction liquid, and the encapsulation efficiency of β-carotene was measured at a wavelength of 450 nm. The results are as Figure 6 shown. Figure 6 In A and B, they are schematic diagrams of the encapsulation efficiency of the emulsion gels obtained after storage at 4 °C and 25 °C for 28 days, respectively. Among them, E20, E30, and E40 are the encapsulation efficiencies of the emulsion gels obtained in Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3, respectively. From Figure 6 it can be seen that the emulsion gels obtained in Examples 1-3 of the present invention have an encapsulation efficiency of β-carotene higher than 70% after storage at 4 °C for 28 days, and the encapsulation efficiency of β-carotene is still not lower than 65% after storage at 25 °C for 28 days.

[0025] It can be seen from the experimental results that the emulsion gel of the present invention significantly improves the encapsulation efficiency of β-carotene and has high freeze-thaw stability.

Claims

1. A preparation method of a carotenoid emulsion gel with high freeze-thaw stability, characterized in that Proceed as follows: Step 1. Prepare the oil phase: Dissolve β-carotene in coconut oil, and the final concentration of β-carotene is 124 - 136 mmol / L; Step 2. Prepare the aqueous phase: Dissolve alginate cellulose in water, and the final concentration of alginate cellulose is 24 - 26 mg / mL; Step 3. Prepare the emulsion gel: Mix the oil phase and the aqueous phase in a mass ratio of 20 - 40:100 and perform high-speed homogenization, and then place it in an environment of 3 - 5 °C and let it stand for 28 - 32 minutes.

2. The preparation method of the carotenoid emulsion gel with high freeze-thaw stability according to claim 1, characterized in that: The speed of the high-speed homogenization in Step 3 is 7000 - 8000 rpm, and the time is 28 - 32 seconds.

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