Preparation method and application of curcumin-loaded spanish mackerel protein / pectin Pickering emulsion

Abstract

The invention discloses a preparation method and application of a curcumin-loaded spanish mackerel protein / pectin Pickering emulsion, and belongs to the field of functional foods. The spanish mackerel protein is extracted through an alkali extraction and acid precipitation method, the spanish mackerel protein and pectin are used as emulsifiers of the high-internal-phase Pickering emulsion, and the high-internal-phase Pickering emulsion is prepared from compounds in different proportions. The storage stability and the thermal stability of the high internal phase emulsion are improved; after oral administration, curcumin can be effectively prevented from being degraded by gastric acid, and the bioavailability of curcumin is improved. In addition, the emulsion also shows good antioxidant activity, and in-vivo evaluation shows that the Spanish mackerel protein-pectin stable emulsion can better relieve colitis, is beneficial to maintaining intestinal health, and has a wide application prospect in the field of functional food development.

Description

Technical Field

[0001] The invention belongs to the field of functional foods, and in particular relates to a preparation method and application of a Spanish mackerel protein / pectin Pickering emulsion loaded with curcumin. Background Art

[0002] Ulcerative colitis (UC) is a common inflammatory disease of the colon characterized by diarrhea, mucosal ulcers, and rectal bleeding. In recent years, the disease has affected millions of patients worldwide, and the incidence of UC has increased rapidly, especially in many developing countries. Currently, the treatment of UC mainly relies on the use of anti-inflammatory drugs, immunomodulatory drugs, and biological products. Several drugs used in clinical practice to relieve UC symptoms, such as corticosteroids and aminosalicylic acid, face the side effects of poor treatment efficiency and strong drug dependence.

[0003] Curcumin (Cur) is a natural polyphenolic pigment extracted from the rhizome of the ginger family Araceae. It is a commonly used condiment and nutritional supplement and the main component of turmeric. Curcumin has been shown to have a variety of functional activities, including antioxidant, anti-inflammatory, antibacterial and anticancer activities. Most importantly, Cur also has the high safety of a compound "generally recognized as safe" by the FDA. Taken together, these results suggest that Cur can be used as a promising therapeutic agent for UC. Despite the development of natural curcumin in nutritional intervention applications, its therapeutic value is limited by its poor water solubility, poor stability, poor intake or low absorption rate, rapid metabolism and poor bioavailability.

[0004] Pickering emulsions are characterized by an emulsification system stabilized by solid particles. They not only have high phase separation resistance, high biocompatibility, and high safety, but also have great potential in texture modification, composite encapsulation, and delivery. Considering that commonly used emulsifiers such as polysorbate-80 can lead to an increased incidence of metabolic syndrome diseases and ulcerative colitis, the trend in the emulsifier industry is to replace synthetic surfactants with more bio- and environmentally friendly alternatives.

[0005] There are many options for solid particle stabilizers, such as protein (whey, zein, caseinate, soy protein), polysaccharides (pectin, chitosan, starch, cellulose, fiber, xanthan gum, alginate) and multi-component particles (polyphenols and the above materials), etc. However, emulsions stabilized by single particles are sensitive to environmental factors and easily destroy the oil-water interface, resulting in thermodynamic instability of the emulsion, which is easy to decompose due to aggregation, flocculation and Ostwald ripening, thus limiting its further development to some extent. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a method for preparing a Spanish mackerel protein / pectin Pickering emulsion loaded with curcumin, wherein Spanish mackerel protein is extracted by an alkali extraction and acid precipitation method, and Spanish mackerel protein and pectin are used as emulsifiers of a high internal phase Pickering emulsion to prepare a high internal phase Pickering emulsion. The storage stability and thermal stability of the high internal phase emulsion of the present invention are improved; after oral administration, the degradation of curcumin by gastric acid can be effectively avoided, thereby improving the bioavailability of curcumin. The emulsion also exhibits good antioxidant activity, can better relieve colitis, is beneficial to maintaining intestinal health, and has broad application prospects in the field of functional food development.

[0007] The present invention provides a method for preparing a Spanish mackerel protein / pectin Pickering emulsion loaded with curcumin, which specifically comprises the following steps:

[0008] (1) Dissolving Spanish mackerel protein and pectin in deionized water to obtain Spanish mackerel protein solution and pectin solution, respectively, and then adjusting the pH values ​​thereof;

[0009] (2) dissolving curcumin in vegetable oil to obtain an oil phase;

[0010] (3) mixing and homogenizing the oil phase and the pectin solution to obtain a mixed solution;

[0011] (4) adding the Spanish mackerel protein solution to the mixed solution of step (3), homogenizing and emulsifying, and obtaining a Spanish mackerel protein / pectin Pickering emulsion loaded with curcumin.

[0012] As an embodiment of the present invention, in step (1), the mass volume ratio of Spanish mackerel protein, pectin and deionized water is (0.5-3):100, g / mL.

[0013] As an embodiment of the present invention, in step (1), the pH of the Spanish mackerel protein solution and the pectin solution is adjusted to 3-6.

[0014] As an embodiment of the present invention, in step (2), the vegetable oil is one or more of corn oil, soybean oil, algae oil, and palm oil.

[0015] As an embodiment of the present invention, in step (2), the added amount of curcumin and vegetable oil is 0.5-2.5:1, mg / mL.

[0016] As an embodiment of the present invention, in step (3), the volume of the pectin solution is 6%-45% of the volume of the oil phase.

[0017] As an embodiment of the present invention, in step (3), the homogenization condition is 8000-10000 rpm for 0.5-3 min.

[0018] As an embodiment of the present invention, in step (3), the oil phase is 60-80% of the volume of the Pickering emulsion.

[0019] As an embodiment of the present invention, in step (4), the mass ratio of Spanish mackerel protein to pectin in the Pickering emulsion is (0.5-3):1.

[0020] As an embodiment of the present invention, in step (4), the homogenization condition is 10000-12000 rpm for 2-3 min.

[0021] As an embodiment of the present invention, in step (1), the method for extracting Spanish mackerel protein specifically comprises:

[0022] (1) Crush Spanish mackerel meat and mix with deionized water;

[0023] (2) adjusting the pH value to alkaline, centrifuging and collecting the supernatant; adjusting the pH value of the supernatant to weak acidity, then standing at 4°C, and finally collecting the protein precipitate by centrifugation;

[0024] (3) The protein precipitate is dispersed in deionized water and freeze-dried to obtain Spanish mackerel protein.

[0025] As an embodiment of the present invention, in step (1), the volume ratio of the ground Spanish mackerel meat to deionized water is 1:(5-15).

[0026] As an embodiment of the present invention, in step (2), a 2 mol / L NaOH solution is used to adjust the pH value to 10-12.

[0027] As an embodiment of the present invention, in step (2), a 2 mol / L HCl solution is used to adjust the pH value to 4-6.

[0028] As an embodiment of the present invention, in step (2), the centrifugation is performed at a speed of 8000-11000 rpm for 10-30 min.

[0029] The invention provides a Spanish mackerel protein / pectin Pickering emulsion loaded with curcumin prepared by the method described above.

[0030] The present invention also provides the use of the above-mentioned Spanish mackerel protein / pectin Pickering emulsion loaded with curcumin in the preparation of a drug for alleviating colitis.

[0031] Beneficial effects of the present invention:

[0032] (1) The Pickering emulsion of the present invention can effectively embed the hydrophobic active factor curcumin and improve its stability under light, heat and UV;

[0033] (2) The present invention can protect curcumin from being damaged by the extreme environment of gastric acid and improve its bioaccessibility.

[0034] (3) The Spanish mackerel protein / pectin-stabilized Pickering emulsion of the present invention can alleviate the symptoms of colitis in mice, including weight loss, reduction in colon length, and significantly improve colon tissue degeneration. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is the zeta potential of Spanish mackerel protein and pectin in Example 1;

[0036] Figure 2 The microscopic images of the high internal phase Pickering emulsion stabilized by Spanish mackerel protein-pectin in Example 2 and the high internal phase Pickering emulsion stabilized by Spanish mackerel protein in Comparative Example 1 and the microscopic images after heating at 95° C. for 30 minutes;

[0037] Figure 3 The rheological properties of the high internal phase Pickering emulsion stabilized by Spanish mackerel protein-pectin in Example 2 and the high internal phase Pickering emulsion stabilized by Spanish mackerel protein in Comparative Example 1 are: the variation of storage modulus (G') and loss modulus (G") with frequency and the variation curve of surface viscosity with shear rate;

[0038] Figure 4 These are microscope pictures of the emulsions of Comparative Examples 3-5 and Example 4;

[0039] Figure 5 The embedding rate and loading efficiency of curcumin in the high internal phase Pickering emulsion stabilized by Spanish mackerel protein-pectin in Example 3 and the high internal phase Pickering emulsion stabilized by Spanish mackerel protein in Comparative Example 2;

[0040] Figure 6 The retention rate of curcumin in the high internal phase Pickering emulsion stabilized by Spanish mackerel protein-pectin loaded with curcumin in Example 3 and the high internal phase Pickering emulsion stabilized by Spanish mackerel protein loaded with curcumin in Comparative Example 2 after storage at room temperature for 14 days and heating at 95° C. for 30 minutes;

[0041] Figure 7 The release rate of curcumin and the bioaccessibility of curcumin in the in vitro digestion experiment of the high internal phase Pickering emulsion stabilized by Spanish mackerel protein-pectin loaded with curcumin in Example 3 and the high internal phase Pickering emulsion stabilized by Spanish mackerel protein loaded with curcumin in Comparative Example 2;

[0042] Figure 8 It is a schematic diagram of the average body weight change of mice after oral administration of curcumin and curcumin-loaded emulsion group;

[0043] Fig. 9 is a graph of the colon length of mice after oral administration of curcumin and curcumin-loaded emulsion groups;

[0044] Fig.10 It is the H&E staining picture of colon tissue sections of mice in the DSS treatment group, free curcumin group, Example 3 and Comparative Example 2 feeding group. DETAILED DESCRIPTION

[0045] This application describes in detail the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the specific conditions and details in the following embodiments.

[0046] The artificial saliva, simulated gastric juice, and simulated intestinal juice used below were all purchased from Beijing Regen Biotechnology Co., Ltd.

[0047] Example 1

[0048] S1. Accurately weigh 0.06 g Spanish mackerel protein and dissolve it in 60 mL of deionized water to prepare a 1 mg / mL Spanish mackerel protein solution. The Spanish mackerel protein solution is evenly divided into 6 portions, and the pH values ​​are adjusted to 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5, respectively.

[0049] S2. Accurately weigh 0.06 g of pectin and dissolve it in 60 mL of deionized water to prepare a 1 mg / mL pectin solution. The pectin solution is evenly divided into 6 portions, and the pH is adjusted to 2.5, 3.5, 4.5, 5.5, 6.5, and 7.5, respectively;

[0050] S3. The above-mentioned solutions with different pH values ​​were measured using a Zeta potential analyzer at 25°C. Figure 1 .

[0051] The surface charges of Spanish mackerel protein and pectin under different pH conditions were determined. Figure 1 As shown in the figure, with the increase of pH, the potential of Spanish mackerel protein gradually decreased from 21.73±1.51mV to -10.53±0.58mV. During the whole pH change process, pectin was negatively charged, because pectin is an anionic polysaccharide. When the pH was around 3, Spanish mackerel protein carried a positive charge, which was opposite to the charge carried by pectin. Therefore, it was speculated that there was electrostatic attraction or other forces between the two.

[0052] Example 2

[0053] A method for preparing a complex-stabilized high internal phase Pickering emulsion mainly comprises the following steps:

[0054] S1. Extraction of Spanish mackerel protein: thaw frozen Spanish mackerel meat, grind it, and mix it with deionized water at a volume ratio of 1:10, then adjust the pH value to 10.5 with 2 mol / L sodium hydroxide solution, stir for 2 hours, centrifuge at 4°C and 9000 rpm for 30 minutes, filter with gauze and take the supernatant; adjust the pH value of the supernatant to 4.5 with 2 mol / L hydrochloric acid, leave it at room temperature for 30 minutes, centrifuge it at 4°C and 8000 rpm for 15 minutes, suspend the obtained protein precipitate in deionized water, then adjust the pH value to 7.0, stir at room temperature for 12 hours, and freeze-dry the obtained supernatant to obtain Spanish mackerel protein;

[0055] S2, fully dissolving Spanish mackerel protein in deionized water to make the final concentration of Spanish mackerel protein solution 2% (w / v); adjusting the pH value of the solution to 3;

[0056] S3, fully dissolving pectin in deionized water to make the final concentration of the pectin solution 2% (w / v); adjusting the pH value of the solution to 3;

[0057] S4, mix 12 mL of the oil phase with 2 mL of the pectin solution in S3, and homogenize using a high-speed digital homogenizer at 10,000 rpm for 1 min;

[0058] S5. Add 2 mL of Spanish mackerel protein solution in S2 to the homogenized mixture, and homogenize again for 2 minutes to obtain an emulsion with a Spanish mackerel protein / pectin mass ratio of 1:1.

[0059] Comparative Example 1

[0060] The preparation method is the same as that of Example 2, except that no pectin solution is added. Specifically,

[0061] In S4, 12 mL of the oil phase was mixed with 2 mL of the 2% w / v Spanish mackerel protein solution in S2, and homogenized for 3 min at 10,000 rpm using a high-speed digital homogenizer; an emulsion stabilized by a single Spanish mackerel protein was obtained.

[0062] Microscope images of the high internal phase Pickering emulsion stabilized by Spanish mackerel protein-pectin in Example 2 and the high internal phase Pickering emulsion stabilized by Spanish mackerel protein in Comparative Example 1 and the microstructures after heating at 95°C for 30 min are shown in FIG. Figure 2As shown, the particle size of the carrier system of Example 2 is smaller and the structure is denser, and the addition of pectin increases the viscosity of the emulsion; the oil droplets of the emulsion carrier system of Comparative Example 1 are larger and uneven, indicating that the emulsion particle size of Example 2 is smaller. Under an optical microscope, the deformation of the oil droplets in Comparative Example 1 under heating conditions can be clearly observed, which may be due to its weak network. In Example 2, the droplet change amplitude of the emulsion is reduced, and there is no obvious deformation phenomenon, which may be due to its more stable emulsion structure and smaller particle size. This result shows that the high internal phase Pickering emulsion prepared in Example 2 has higher temperature stability, which is beneficial to the application of emulsions in food production.

[0063] The rheological properties of the emulsion were measured using a rheometer. Figure 3 As shown, the storage modulus (G') and loss modulus (G") of the Pickering emulsions as well as the apparent shear viscosity of the emulsions were measured at a fixed strain (1% in the LVR range) in the frequency range of 0.1 Hz to 10 Hz, with a shear rate range of 0.1 s -1 ~100s -1 . Within the measurement range, G' of all HIPPEs is greater than G", and elasticity is dominant, indicating that the emulsion has gel properties similar to elastic solids. G' and G" of Example 2 are both greater than those of Comparative Example 1, indicating that the emulsion prepared in Example 2 has excellent elasticity, which may be due to the interaction force between protein and polysaccharide at the water-oil interface and the thickening effect of pectin. It can be seen that the addition of pectin is beneficial to enhancing the network structure of the emulsion. With the increase of shear rate, all HIPPEs show shear thinning characteristics, which is a typical feature of non-Newtonian fluids.

[0064] The emulsion prepared in Example 2 has the highest viscosity. Higher viscosity will hinder the movement of oil droplets and improve the stability of the emulsion.

[0065] Example 3

[0066] This embodiment is a method for preparing a high internal phase Pickering emulsion stabilized by a Spanish mackerel protein-pectin complex loaded with curcumin, which mainly comprises the following steps:

[0067] S1. Extraction of Spanish mackerel protein: thaw frozen Spanish mackerel, grind and mix with deionized water at a volume ratio of 1:10, then adjust the pH value to 10.5 with 2 mol / L sodium hydroxide solution, stir for 2 hours, centrifuge at 4°C and 9000 rpm for 30 minutes, filter through gauze to obtain the supernatant, adjust the pH value of the supernatant to 4.5 with 2 mol / L hydrochloric acid, leave at room temperature for 30 minutes, centrifuge at 4°C and 8000 rpm for 15 minutes, suspend the obtained protein precipitate in deionized water, then adjust the pH value to 7.0, stir at room temperature for 12 hours, and freeze-dry the obtained supernatant to obtain Spanish mackerel protein;

[0068] S2, fully dissolving Spanish mackerel protein in deionized water to make the final concentration of Spanish mackerel protein solution be 2% (w / v), and adjusting the pH value of the solution to 3;

[0069] S3, fully dissolving pectin in deionized water to make the final concentration of the pectin solution 2% (w / v), and adjusting the pH value of the solution to 3;

[0070] S4, dissolving curcumin in corn oil to obtain an oil phase (2 mg / mL), and stirring (500 rpm) for 12 h in the dark at room temperature; mixing 12 mL of the oil phase with 2 mL of the pectin solution in S3, and homogenizing with a high-speed digital homogenizer at 10,000 rpm for 1 min to obtain a mixed solution;

[0071] S5. Add 2 mL of Spanish mackerel protein solution in S2 to the homogenized mixed solution, and homogenize again for 2 minutes to obtain an emulsion with a Spanish mackerel protein / pectin mass ratio of 1:1.

[0072] Comparative Example 2

[0073] This embodiment is a method for preparing a high internal phase Pickering emulsion stabilized by Spanish mackerel protein loaded with curcumin, which mainly comprises the following steps:

[0074] The preparation method is the same as that of Example 3, except that no pectin solution is added. Specifically,

[0075] In S4, 12 mL of the oil phase was mixed with 2 mL of the 2% w / v Spanish mackerel protein solution in S2, and homogenized for 3 min at 10,000 rpm using a high-speed digital homogenizer; an emulsion stabilized by a single Spanish mackerel protein was obtained.

[0076] Comparative Example 3

[0077] The preparation method is the same as that of Example 3, except that the prepared Spanish mackerel protein is replaced by cod protein.

[0078] Comparative Example 4

[0079] The preparation method is the same as that of Example 3, except that pectin is replaced by chitosan.

[0080] Comparative Example 5

[0081] The preparation method is the same as that in Example 3, except that: in S4 and S5, the Spanish mackerel protein solution is first mixed with the oil phase, homogenized, and then mixed with the pectin solution, specifically:

[0082] S4, dissolving curcumin in corn oil to obtain an oil phase (2 mg / mL), and stirring (500 rpm) for 12 h in the dark at room temperature; mixing 12 mL of the oil phase with 2 mL of the Spanish mackerel protein solution in S2, and homogenizing with a high-speed digital homogenizer at 10000 rpm for 1 min to obtain a mixed solution;

[0083] S5. Add 2 mL of the pectin solution in S3 to the homogenized mixed solution, and homogenize again for 2 minutes to obtain an emulsion with a Spanish mackerel protein / pectin mass ratio of 1:1.

[0084] Example 4

[0085] This example is the effect of pH on the high internal phase Pickering emulsion stabilized by Spanish mackerel protein loaded with curcumin

[0086] The preparation method is the same as that of Example 3, except that the pH in the preparation steps S2 and S3 is adjusted to 4, 5, and 6.

[0087] like Figure 4 As shown, the microscope picture of comparative example 3 shows that the particle size of the emulsion is uneven, and the larger oil droplets are deformed. The particle size of comparative example 4 is larger, and the oil droplets break faster under the microscope. The oil droplets of comparative example 5 aggregate under the microscope, accompanied by the deformation of the large oil droplets. When the pH of the aqueous phase is adjusted to 4, 5, and 6, it can be seen that the particle size of the emulsion is larger than that at pH 3, indicating that pH has a significant effect on the effect of the present invention.

[0088] The performance of the emulsion prepared in Example 3 was tested:

[0089] like Figure 5 As shown, the curcumin encapsulation rates in Example 3 and Comparative Example 2 are 89.82±0.08% and 85.22±0.26%, respectively. The loading efficiency of curcumin in the emulsion prepared in Example 3 is also higher than that in Comparative Example 2, indicating that the emulsion prepared by the implementation steps in Example 3 has the best encapsulation effect.

[0090] The emulsions prepared in Example 3 and Comparative Example 2 were placed at room temperature for 14 days or heated in a 95°C water bath for 30, 60, 90, 120, 150, 180, and 210 minutes. The curcumin content in the solution was determined using a pre-established standard curve and the curcumin retention rate was calculated. Figure 6As shown, after 14 days of storage at room temperature, the curcumin preservation rates of oil, i.e., single curcumin (curcumin dissolved in corn oil, 2 mg / mL), comparative example 2 and example 3 were 67.34 ± 0.24%, 75.04 ± 0.46% and 84.37 ± 0.38%, respectively. This shows that the high internal phase Pickering emulsion stabilized by Spanish mackerel protein-pectin in example 3 has better UV stability. After heating for 210 min, the curcumin preservation rates of oil, i.e., single curcumin, comparative example 2 and example 3 were 38.96 ± 0.38%, 48.74 ± 0.27% and 61.22 ± 0.10%, respectively. This shows that the emulsion stabilized by the complex prepared in example 3 has better thermal stability.

[0091] The emulsion samples, artificial saliva (SSF), simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) prepared in Example 3 and Comparative Example 2 were incubated at 37°C for 10 min before use. Secondly, 0.4 mL of the emulsion sample was incubated with 7.1 mL of artificial saliva at 37°C for 5 min. Then, 7.5 mL of SGF was added and incubated at 37°C for 120 min to simulate gastric digestion. After gastric digestion, the sample was mixed with 7.5 mL of SIF and incubated at 37°C for 120 min to simulate intestinal digestion. 1 mL of supernatant was taken out from the mixed solution every 30 minutes, the curcumin concentration was detected and an equal amount of simulated intestinal fluid was supplemented. Figure 7 As shown, the release amount of curcumin in simulated gastric juice and simulated intestinal juice of Example 3 and Comparative Example 2 is significantly lower than the stable emulsion of Comparative Example 2 in the whole gastric digestion process. The network structure formed by adding pectin in the emulsion prepared in Example 3 inhibits the release of curcumin into the gastric phase and prevents its degradation. In the intestinal digestion process, the curcumin in Example 3 is released quickly, and the total release rate is 48.17±0.18%. Example 3 has a smaller oil droplet size and a smaller specific surface area, which strengthens the contact between the oil droplet and the lipase and accelerates the release of curcumin in the intestinal digestion process. Compared with free curcumin (14.05±0.14%) in oil, corn oil, Example 3 and Comparative Example 2 significantly improve the bioaccessibility of curcumin, and the bioaccessibility of curcumin in Comparative Example 2 and Example 3 is 26.4±0.04% and 37.51±2.04%, respectively. Example 3 can inhibit the degradation of curcumin during digestion, and smaller droplets help curcumin to be effectively transferred to the micelle component, thereby further improving the bioaccessibility of curcumin.

[0092] High internal phase Pickering emulsion stabilized by Spanish mackerel protein / pectin improves colitis symptoms

[0093] After 7 days of acclimation, 50 SPF male BALB / c mice (7 weeks old) were divided into 5 groups (n=10), namely, a control group, a dextran sulfate sodium salt (DSS) group, a free curcumin group, a Spanish mackerel protein-curcumin group, and a Spanish mackerel protein / pectin-curcumin group, specifically: control group: gavage with deionized water; DSS group: gavage with deionized water; free curcumin group: gavage with free curcumin (curcumin dissolved in oil); Spanish mackerel protein-curcumin group: gavage with the emulsion prepared in Comparative Example 2; Spanish mackerel protein / pectin-curcumin group: gavage with the emulsion prepared in Example 3.

[0094] The oral doses of free curcumin, Spanish mackerel protein-curcumin, and Spanish mackerel protein / pectin-curcumin were 15 mg / kg / day, respectively. Except for the control group, rats in the other groups were intragastrically administered with 3.5% DSS for 7 days to induce colitis, and the body weight of the mice was recorded every three days.

[0095] Figure 8 This is a graph showing the average weight change of mice after oral administration of curcumin and curcumin-loaded emulsion. The effect of DSS caused the mice to lose weight. Compared with the DSS group, the weight of mice in the free curcumin group, the Spanish mackerel protein-curcumin group and the Spanish mackerel protein / pectin-curcumin group all increased. Among them, the weight of mice in Example 3, i.e. the Spanish mackerel protein / pectin-curcumin group, increased the most, indicating that Example 3 has a better intervention effect on weight loss in colitis than Comparative Example 2.

[0096] Fig. 9 : is a graph of the colon length of mice after oral administration of curcumin and curcumin-loaded emulsion. Compared with the DSS group, the colon of the free curcumin group, the Spanish mackerel protein-curcumin group and the Spanish mackerel protein / pectin-curcumin group increased by 0.45 cm, 0.52 cm and 0.98 cm, respectively, indicating that Example 3 has the best effect on improving the colon shortening phenomenon of colitis symptoms.

[0097] Fig.10 It is an H&E staining image of the colon tissue sections of mice in the DSS-treated group, the free curcumin group, the Example 3 and the Comparative Example 2 feeding group. Compared with the control group, DSS caused swelling and destruction of the crypts, mucosal detachment, and epithelial cell damage. The histological structure of the colon showed improvement after administration. The degree of relief in the Comparative Example 2 feeding group and the Example 3 feeding group was more obvious, and the state of the Example 3 feeding group was significantly better than that of the Comparative Example 2 feeding group; the Example 3 feeding group showed the best colon histological recovery, showing a relatively complete crypt structure, reduced goblet cell loss, and significantly reduced macrophage infiltration. It is proved that compared with the single Spanish mackerel protein-stabilized emulsion delivery system, the Spanish mackerel protein / pectin complex delivery system has a better intervention effect on colitis.

[0098] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a curcumin-loaded Spanish mackerel protein / pectin Pickering emulsion, characterized in that: The specific steps include: (1) Dissolving Spanish mackerel protein and pectin in deionized water to obtain Spanish mackerel protein solution and pectin solution, respectively, and then adjusting the pH values ​​thereof; (2) dissolving curcumin in vegetable oil to obtain an oil phase; (3) mixing and homogenizing the oil phase and the pectin solution to obtain a mixed solution; (4) adding the Spanish mackerel protein solution to the mixed solution of step (3), homogenizing and emulsifying, and obtaining a Spanish mackerel protein / pectin Pickering emulsion loaded with curcumin.

2. The method for preparing a curcumin-loaded Spanish mackerel protein / pectin Pickering emulsion according to claim 1, characterized in that: In step (1), the mass volume ratio of Spanish mackerel protein, pectin and deionized water is (0.5-3):100, g / mL.

3. The method for preparing a curcumin-loaded Spanish mackerel protein / pectin Pickering emulsion according to claim 1, characterized in that: In step (1), the pH of the Spanish mackerel protein solution and the pectin solution is adjusted to 3-6.

4. The method for preparing a curcumin-loaded Spanish mackerel protein / pectin Pickering emulsion according to claim 1, characterized in that: In step (2), the vegetable oil is one or more of corn oil, soybean oil, algae oil, and palm oil.

5. The method for preparing a curcumin-loaded Spanish mackerel protein / pectin Pickering emulsion according to claim 1, characterized in that: In step (2), the addition ratio of curcumin and vegetable oil is 0.5-2.5:1, mg / mL.

6. The method for preparing a curcumin-loaded Spanish mackerel protein / pectin Pickering emulsion according to claim 1, characterized in that: In step (3), the volume of the pectin solution is 6-45% of the volume of the oil phase; and the oil phase is 60-80% of the volume of the Pickering emulsion.

7. The method for preparing a curcumin-loaded Spanish mackerel protein / pectin Pickering emulsion according to claim 1, characterized in that: In step (4), the mass ratio of Spanish mackerel protein to pectin in the Pickering emulsion is (0.5-3):

1.

8. The method for preparing a curcumin-loaded Spanish mackerel protein / pectin Pickering emulsion according to claim 1, characterized in that: In step (1), the method for extracting Spanish mackerel protein specifically comprises: (1) Crush Spanish mackerel meat and mix it with deionized water in a volume ratio of 1:(5-15); (2) adjusting the pH value to 10-12, centrifuging and collecting the supernatant; adjusting the pH value of the supernatant to 4-6, letting it stand, and finally collecting the protein precipitate by centrifugation; (3) The protein precipitate is dispersed in deionized water and freeze-dried to obtain Spanish mackerel protein.

9. The Spanish mackerel protein / pectin Pickering emulsion loaded with curcumin prepared by any one of the methods of claims 1-8.

10. Use of the curcumin-loaded Spanish mackerel protein / pectin Pickering emulsion according to claim 9 in the preparation of a drug for relieving colitis.

Images