Coconut oil / starch double emulsion embedded with water-soluble anthocyanin and preparation method of coconut oil / starch double emulsion

Abstract

The invention provides a water-soluble anthocyanin embedded coconut oil / starch double emulsion and a preparation method thereof, and the preparation method comprises the following specific steps: S1, mixing coconut oil and a lipophilic emulsifier, and heating to obtain an oil phase; s2, adding anthocyanin and cane sugar into a citric acid solution to obtain a water phase; s3, adding the water phase into the oil phase, shearing at a high speed, and homogenizing to obtain a W1 / O type single emulsion embedded with the water-soluble functional factors; s4, maltodextrin and starch are added into water to be heated and gelatinized, and a starch-based water phase W2 is obtained; and S5, slowly adding the starch-based water phase W2 into the W1 / O type single emulsion, uniformly mixing, and standing to obtain a water-soluble functional factor embedded W1 / O / W2 type starch-based double emulsion, namely the water-soluble anthocyanin embedded coconut oil / starch double emulsion. The preparation process is simple, green, environment-friendly and low in cost, the obtained double emulsion has high storage stability, digestion characteristics of anthocyanin, starch and coconut oil can be remarkably improved, the bioavailability in the body is high after oral taking, and the application prospect is good.

Description

Technical Field

[0001] The invention relates to the technical field of emulsions, and in particular to a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins and a preparation method thereof. Background Art

[0002] As people's awareness of healthy nutrition increases, fat-soluble functional factors that improve the health level of the body are increasingly attracting people's attention. The physiological activity of anthocyanins that is beneficial to health has been widely studied and verified, but anthocyanins have shortcomings such as sensitivity to environmental conditions and low absorption rate, which leads to low bioavailability in the body after oral ingestion, hindering the performance and utilization of the biological activity of proanthocyanidins. Although its bioavailability has been improved from different angles, the effect is still not good. Generally, an emulsion delivery system is used to embed it in the oil phase, thereby effectively protecting and improving its biological activity. Double emulsion, as an emulsion delivery system, can effectively control the slow and continuous release of functional factors under the specific environment of the gastrointestinal tract, which is conducive to the absorption and utilization of functional factors. However, most of the current research on double emulsions focuses on the investigation of the controlled and sustained release performance of functional factors in the gastrointestinal tract, but ignores the absorption and utilization of functional factors. Summary of the invention

[0003] In view of this, the present invention provides a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins and a preparation method thereof.

[0004] The technical solution of the present invention is achieved in this way:

[0005] A method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanins, the specific steps comprising:

[0006] S1, mixing and heating coconut oil and a lipophilic emulsifier to obtain an oil phase;

[0007] S2, adding anthocyanidins and sucrose to the citric acid solution to obtain an aqueous phase;

[0008] S3, adding the water phase to the oil phase, high-speed shearing, and homogenization to obtain a W1 / O type single emulsion encapsulating the water-soluble functional factors;

[0009] S4, adding maltodextrin and starch into water, heating and gelling, and obtaining a starch-based aqueous phase W2;

[0010] S5. Slowly add the starch-based aqueous phase W2 to the W1 / O type single emulsion, mix evenly, and let stand to obtain a W1 / O / W2 type starch-based double emulsion encapsulating water-soluble functional factors, that is, a coconut oil / starch double emulsion encapsulating water-soluble anthocyanins.

[0011] Furthermore, in step S1, the mass content of coconut oil in the oil phase is 92%-98%, and the mass content of lipophilic emulsifier is 2%-8%; the temperature of the mixed heating is 80-90° C., and the time is 10-20 min.

[0012] Furthermore, the lipophilic emulsifier is polyglycerol polyricinoleate or Tween 20.

[0013] Furthermore, in step S2, the anthocyanin is acai berry anthocyanin, and its mass content in the aqueous phase is 1% to 2%; the mass content of sucrose in the aqueous phase is 3% to 4%.

[0014] Furthermore, in step S2, the concentration of the citric acid solution is 0.02-0.1 mol / L, and the pH is 3.6-3.8.

[0015] Furthermore, in step S3, the mass ratio of the water phase to the oil phase is (1:4) to (4:1); the rotation speed of the high-speed shear is 10000 to 12000 rpm, and the time is 10 to 20 min; the homogenization pressure is 5 to 10 MPa, and the time is 3 to 5 min.

[0016] Furthermore, in step S4, the starch content in the starch-based aqueous phase W2 is 3% to 10% w / v; and the mass ratio of maltodextrin to starch is (3:1) to (1:3).

[0017] Furthermore, the starch is any one of tapioca starch, potato starch or pea starch.

[0018] Furthermore, in step S5, the mass ratio of the starch-based aqueous phase W2 to the W1 / O type single emulsion is (1:4) to (4:1).

[0019] A coconut oil / starch double emulsion for embedding water-soluble anthocyanidin is prepared by the preparation method.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The preparation process of the present invention is simple, green and environmentally friendly, and has low cost. The obtained coconut oil / starch double emulsion for embedding water-soluble anthocyanins has high storage stability and can effectively reduce the damage of external environmental factors to functional factors.

[0022] 2. Compared with anthocyanidins and starch foods alone, the coconut oil / starch double emulsion encapsulating water-soluble anthocyanidins obtained in the present invention can not only increase the bioavailability of anthocyanidins, but also increase the tolerance of starch to α-amylase, reduce blood sugar increase, and improve digestion characteristics. It has high bioavailability in the body after oral ingestion, has good application prospects, and has practical significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the appearance of the coconut oil / starch double emulsion encapsulating water-soluble anthocyanins of Examples 1-9.

[0024] Figure 2 The microstructure of the coconut oil / starch double emulsion encapsulating water-soluble anthocyanins of Examples 1-9.

[0025] Figure 3 Graph showing the reducing sugar release rate of the starch in the coconut oil / starch double emulsions encapsulating water-soluble anthocyanins of Examples 2, 3 and Examples 6-12 after hydrolysis by α-amylase.

[0026] Among them, Example 2 is potato starch 5% w / v, Example 6 is tapioca starch 5% w / v, Example 7 is pea starch 5% w / v, Example 3 is pea starch 10% w / v, Example 8 is tapioca starch 10% w / v, Example 9 is potato starch 10% w / v, Example 10 is tapioca starch 7% w / v, Example 11 is potato starch 7% w / v, and Example 12 is pea starch 7% w / v.

[0027] Figure 4 Rheological properties of coconut oil / starch double emulsion encapsulating water-soluble anthocyanins. DETAILED DESCRIPTION

[0028] In order to better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0029] Unless otherwise specified, the experimental methods used in the embodiments of the present invention are all conventional methods.

[0030] Unless otherwise specified, the materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources.

[0031] Example 1

[0032] A method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanins, the specific steps comprising:

[0033] S1, 95% coconut oil and 5% polyglycerol castor oil ester were mixed, and heated at 85°C for 15 minutes to obtain an oil phase;

[0034] S2, adding 1% w / v acai berry anthocyanidin and 3% w / v sucrose to a 0.05 mol / L citric acid solution (pH=3.8±0.2) to obtain an aqueous phase;

[0035] S3, adding the water phase to the oil phase at a mass ratio of 3:2, shearing at 11000 rpm for 15 min, and homogenizing at 8 MPa for 4 min to obtain a W1 / O type single emulsion encapsulating the water-soluble functional factors;

[0036] S4, adding maltodextrin and tapioca starch in a mass ratio of 1:1 into water, wherein the tapioca starch content is 3% w / v, and heating to gelatinize to obtain a type A emulsion, i.e., a starch-based aqueous phase W2;

[0037] S5. Slowly add the starch-based aqueous phase W2 to the W1 / O type single emulsion at a mass ratio of 2:3, mix evenly, and let stand to obtain a W1 / O / W2 type starch-based double emulsion encapsulating water-soluble functional factors, i.e., a coconut oil / starch double emulsion encapsulating water-soluble anthocyanins.

[0038] Example 2

[0039] A method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanins, the specific steps comprising:

[0040] S1, 92% coconut oil and 8% Tween 20 were mixed and heated at 80°C for 10 min to obtain an oil phase;

[0041] S2, adding 2% w / v acai berry anthocyanidins and 3% w / v sucrose to a 0.02 mol / L citric acid solution (pH = 3.8 ± 0.2) to obtain an aqueous phase;

[0042] S3, adding the water phase to the oil phase at a mass ratio of 1:4, shearing at 10000 rpm for 10 min, and homogenizing at 5 MPa for 3 min to obtain a W1 / O type single emulsion encapsulating the water-soluble functional factors;

[0043] S4, adding maltodextrin and potato starch in a mass ratio of 3:1 into water, wherein the potato starch content is 5% w / v, and heating to gelatinize to obtain a type B emulsion, a starch-based aqueous phase W2;

[0044] S5. Slowly add the starch-based aqueous phase W2 to the W1 / O type single emulsion at a mass ratio of 1:4, mix evenly, and let stand to obtain a W1 / O / W2 type starch-based double emulsion encapsulating water-soluble functional factors, i.e., a coconut oil / starch double emulsion encapsulating water-soluble anthocyanins.

[0045] Example 3

[0046] A method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanins, the specific steps comprising:

[0047] S1, mixing 98% coconut oil and 2% polyglycerol ricinoleate, heating at 90°C for 20min to obtain an oil phase;

[0048] S2, adding 1% w / v acai berry anthocyanidin and 4% w / v sucrose to a 0.1 mol / L citric acid solution (pH = 3.8 ± 0.2) to obtain an aqueous phase;

[0049] S3, adding the water phase to the oil phase at a mass ratio of 4:1, shearing at 12000 rpm for 20 min, and homogenizing at 10 MPa for 5 min to obtain a W1 / O type single emulsion encapsulating the water-soluble functional factors;

[0050] S4, adding maltodextrin and pea starch in a mass ratio of 1:3 into water, wherein the pea starch content is 10% w / v, and heating to gelatinize to obtain a type C emulsion, a starch-based aqueous phase W2;

[0051] S5. Slowly add the starch-based aqueous phase W2 to the W1 / O type single emulsion at a mass ratio of 4:1, mix evenly, and let stand to obtain a W1 / O / W2 type starch-based double emulsion encapsulating water-soluble functional factors, i.e., a coconut oil / starch double emulsion encapsulating water-soluble anthocyanins.

[0052] Example 4

[0053] On the basis of Example 1, the tapioca starch in the type A emulsion in step S4 is replaced by potato starch, that is, the content of potato starch is 3% w / v.

[0054] Example 5

[0055] On the basis of Example 1, the tapioca starch in the type A emulsion in step S4 is replaced by pea starch, that is, the content of pea starch is 3% w / v.

[0056] Example 6

[0057] On the basis of Example 2, the potato starch in the type B emulsion in step S4 is replaced by tapioca starch, that is, the content of tapioca starch is 5% w / v.

[0058] Example 7

[0059] On the basis of Example 2, the potato starch in the type B emulsion in step S4 is replaced by pea starch, that is, the content of pea starch is 5% w / v.

[0060] Example 8

[0061] On the basis of Example 3, the pea starch in the C-type emulsion in step S4 is replaced by tapioca starch, that is, the content of tapioca starch is 10% w / v.

[0062] Example 9

[0063] On the basis of Example 3, the pea starch in the C-type emulsion in step S4 is replaced by potato starch, that is, the content of potato starch is 10% w / v.

[0064] Test Example 1

[0065] The coconut oil / starch double emulsions encapsulating water-soluble anthocyanins of Examples 1-9 were placed on a glass slide, covered with a cover glass, and observed and photographed under a microscope.

[0066] Reference Figure 2 It can be seen that no matter any of cassava starch, potato starch and pea starch, the type and microstructure of emulsion formed are different with the different solid content, indicating that the type and content of different starch affect the structure of double emulsion.

[0067] Example 10

[0068] A method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanins, the specific steps comprising:

[0069] S1, 95% coconut oil and 5% polyglycerol castor oil ester were mixed, and heated at 85°C for 15 minutes to obtain an oil phase;

[0070] S2, adding 1% w / v acai berry anthocyanidin and 3% w / v sucrose to a 0.05 mol / L citric acid solution (pH=3.8±0.2) to obtain an aqueous phase;

[0071] S3, adding the water phase to the oil phase at a mass ratio of 3:2, shearing at 11000 rpm for 15 min, and homogenizing at 8 MPa for 4 min to obtain a W1 / O type single emulsion encapsulating the water-soluble functional factors;

[0072] S4, adding maltodextrin and tapioca starch in a mass ratio of 1:1 into water, wherein the tapioca starch content is 7% w / v, and heating to gelatinize to obtain a starch-based aqueous phase W2;

[0073] S5. Slowly add the starch-based aqueous phase W2 to the W1 / O type single emulsion at a mass ratio of 2:3, mix evenly, and let stand to obtain a W1 / O / W2 type starch-based double emulsion encapsulating water-soluble functional factors, i.e., a coconut oil / starch double emulsion encapsulating water-soluble anthocyanins.

[0074] Embodiment 11

[0075] A method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanins, the specific steps comprising:

[0076] S1, 92% coconut oil and 8% Tween 20 were mixed and heated at 80°C for 10 min to obtain an oil phase;

[0077] S2, adding 2% w / v acai berry anthocyanidins and 3% w / v sucrose to a 0.02 mol / L citric acid solution (pH = 3.8 ± 0.2) to obtain an aqueous phase;

[0078] S3, adding the water phase to the oil phase at a mass ratio of 1:4, shearing at 10000 rpm for 10 min, and homogenizing at 5 MPa for 3 min to obtain a W1 / O type single emulsion encapsulating the water-soluble functional factors;

[0079] S4, adding maltodextrin and potato starch in a mass ratio of 3:1 into water, wherein the potato starch content is 7% w / v, and heating to gelatinize to obtain a starch-based aqueous phase W2;

[0080] S5. Slowly add the starch-based aqueous phase W2 to the W1 / O type single emulsion at a mass ratio of 1:4, mix evenly, and let stand to obtain a W1 / O / W2 type starch-based double emulsion encapsulating water-soluble functional factors, i.e., a coconut oil / starch double emulsion encapsulating water-soluble anthocyanins.

[0081] Example 12

[0082] A method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanins, the specific steps comprising:

[0083] S1, mixing 98% coconut oil and 2% polyglycerol ricinoleate, heating at 90°C for 20min to obtain an oil phase;

[0084] S2, adding 1% w / v acai berry anthocyanidin and 4% w / v sucrose to a 0.1 mol / L citric acid solution (pH = 3.8 ± 0.2) to obtain an aqueous phase;

[0085] S3, adding the water phase to the oil phase at a mass ratio of 4:1, shearing at 12000 rpm for 20 min, and homogenizing at 10 MPa for 5 min to obtain a W1 / O type single emulsion encapsulating the water-soluble functional factors;

[0086] S4, adding maltodextrin and pea starch in a mass ratio of 1:3 into water, wherein the pea starch content is 7% w / v, and heating to gelatinize to obtain a starch-based aqueous phase W2;

[0087] S5. Slowly add the starch-based aqueous phase W2 to the W1 / O type single emulsion at a mass ratio of 4:1, mix evenly, and let stand to obtain a W1 / O / W2 type starch-based double emulsion encapsulating water-soluble functional factors, i.e., a coconut oil / starch double emulsion encapsulating water-soluble anthocyanins.

[0088] Test Example 2

[0089] The encapsulation rate of the coconut oil / starch double emulsions encapsulating water-soluble anthocyanins of Examples 10-12 and the bioavailability of anthocyanins in the gastrointestinal tract after oral ingestion were calculated, and anthocyanins without loading were used as a control group.

[0090] Wherein, embedding rate = (anthocyanin content of W1 / O type single emulsion - anthocyanin content of W2 migrated to starch-based aqueous phase in double emulsion) / anthocyanin content of W1 / O type single emulsion × 100%

[0091] The results are shown in Table 1.

[0092] Table 1

[0093] sample Anthocyanin embedding rate / % Anthocyanin bioavailability / % Example 10 98.23±0.66a 39.65±0.22c Embodiment 11 92.11±0.53c 62.44±0.57a Example 12 95.46±0.72b 46.53±0.36b Control group - 16.37±0.12d

[0094] Note: a, b, c, d indicate significant differences between groups, p<0.05

[0095] As can be seen from Table 1, the embedding rates of the coconut oil / tapioca starch-based double emulsion for embedding water-soluble anthocyanidins of Example 10, the coconut oil / potato starch-based double emulsion for embedding water-soluble anthocyanidins of Example 11, and the coconut oil / pea starch-based double emulsion for embedding water-soluble anthocyanidins of Example 12 are all greater than 90%, indicating that anthocyanidins can be efficiently loaded in starch-based double emulsions, among which the coconut oil / tapioca starch-based double emulsion for embedding water-soluble anthocyanidins of Example 10 has the highest embedding rate of 98.23%.

[0096] At the same time, relative to unloaded anthocyanins, the bioavailability of the coconut oil / cassava starch-based double emulsion encapsulating water-soluble anthocyanins of Example 10, the coconut oil / potato starch-based double emulsion encapsulating water-soluble anthocyanins of Example 11, and the coconut oil / pea starch-based double emulsion encapsulating water-soluble anthocyanins of Example 12 was significantly increased.

[0097] Test Example 3

[0098] The ability of starch to tolerate α-amylase was tested on the coconut oil / starch double emulsions containing water-soluble anthocyanins prepared in Examples 2, 3, 6-12.

[0099] Specific method: 500 mg of the emulsion sample to be tested was dispersed in 5 mL of phosphate buffer (0.02 mol / L, pH 6.9) containing α-amylase (50 U / L) and calcium chloride (3 mmol / L), and the suspension was heated in a 37°C water bath with stirring. Take 1 mL of total solution at 0, 30, 60 and 90 min, add 1 mL of DNS reagent (weigh 10±0.1 g of 3,5-dinitrosalicylic acid, add to about 600 mL of water, gradually add 10 g of sodium hydroxide, stir and dissolve in a 50°C water bath. Then add 200 g of sodium methyl tartrate, 2 g of phenol and 5 g of anhydrous sodium sulfite in sequence. After all are dissolved and clarified, cool to room temperature, dilute to 1000 mL with water, filter and store in a brown reagent bottle, and place in the dark for 7 days before use) to terminate the reaction, and immediately boil in a water bath for 5 min to kill the enzyme. After cooling to room temperature, centrifuge at 10000 r / min for 10 min to separate the supernatant, take 0.5 mL of supernatant and dilute to 5 mL, and measure the absorbance at 540 nm. Use phosphate buffer as blank to adjust to zero, and double emulsion without anthocyanin as sample blank. Calculate the reducing sugar release rate.

[0100] Reducing sugar release rate = reducing sugar content of double emulsion containing anthocyanins / reducing sugar content of double emulsion without anthocyanins × 100%

[0101] The experimental results are as follows Figure 3 The reducing sugar release rate of starch in double emulsions after hydrolysis by α-amylase shows that the reducing sugar release of different types of starch in double emulsions decreased during digestion compared with samples without anthocyanins, especially in double emulsions prepared with 10% potato starch, the reducing sugar release was only about 30% of that without anthocyanins. However, double emulsions have different effects on the relative release rate of reducing sugars of different concentrations and types of starch, among which the reducing sugar release rate of pea starch>the reducing sugar release rate of cassava starch>the reducing sugar release rate of potato starch. This shows that the tolerance of different types and concentrations of starch in double emulsions to α-amylase is improved, which can reduce the increase in blood sugar caused by consuming starch alone.

[0102] Comparative Example 1

[0103] The difference from Example 10 is that anthocyanin is missing, and the rest is consistent with Example 10.

[0104] The preparation method of the emulsion of this comparative example comprises the following specific steps:

[0105] S1, 95% coconut oil and 5% polyglycerol castor oil ester were mixed, and heated at 85°C for 15 minutes to obtain an oil phase;

[0106] S2, adding maltodextrin and tapioca starch in a mass ratio of 1:1 into water, wherein the tapioca starch content is 7% w / v, and heating to gelatinize to obtain a starch-based aqueous phase;

[0107] S3. Slowly add the starch-based aqueous phase into the oil phase at a mass ratio of 2:3, shear at 11000 rpm for 15 min, and homogenize at 8 MPa for 4 min to obtain the target emulsion.

[0108] Comparative Example 2

[0109] The difference from Example 11 is that anthocyanin is missing, and the rest is consistent with Example 11.

[0110] The preparation method of the emulsion of this comparative example comprises the following specific steps:

[0111] S1, 92% coconut oil and 8% Tween 20 were mixed and heated at 80°C for 10 min to obtain an oil phase;

[0112] S2, adding maltodextrin and potato starch in a mass ratio of 3:1 into water, wherein the potato starch content is 7% w / v, and heating to gelatinize to obtain a starch-based aqueous phase;

[0113] S3. Slowly add the starch-based aqueous phase into the oil phase at a mass ratio of 1:4, shear at 10,000 rpm for 10 min, and homogenize at 5 MPa for 3 min to obtain the target emulsion.

[0114] Comparative Example 3

[0115] The difference from Example 12 is that anthocyanin is missing, and the rest is consistent with Example 12.

[0116] The preparation method of the emulsion of this comparative example comprises the following specific steps:

[0117] S1, mixing 98% coconut oil and 2% polyglycerol ricinoleate, heating at 90°C for 20min to obtain an oil phase;

[0118] S2, adding maltodextrin and pea starch in a mass ratio of 1:3 into water, wherein the pea starch content is 7% w / v, and heating to gelatinize to obtain a starch-based aqueous phase;

[0119] S3. Slowly add the starch-based aqueous phase into the oil phase at a mass ratio of 4:1, shear at 12000 rpm for 20 min, and homogenize at 10 MPa for 5 min to obtain the target emulsion.

[0120] Test Example 4

[0121] The double emulsions prepared in Examples 10-12 and the emulsions prepared in Comparative Examples 1-3 were tested for the free fatty acid release rate of coconut oil.

[0122] Specific method: simulate the gastrointestinal digestion environment, and use potassium hydroxide neutralization method to determine the free fatty acid content at 30min, 60min, 90min, 120min, 150min, 180min, 210min and 240min. During the gastrointestinal digestion process, the free fatty acid release rate of the coconut oil in Examples 10-12 was compared with the free fatty acid release rate of the coconut oil in Comparative Examples 1-3, and the results are shown in Table 2.

[0123] Table 2

[0124]

[0125] Note: * indicates significant difference compared with the control group, p<0.05

[0126] As can be seen from Table 2, the addition of anthocyanins in the embodiments of the present invention has a relatively small effect on the free fatty acid release rate of coconut oil in the simulated gastric digestion process. The release rate of free fatty acids increases rapidly when transitioning to the simulated intestinal digestion stage. The release rates of free fatty acids in Examples 10-12 are significantly higher than those in Comparative Examples 1-3, indicating that the double emulsion of the present invention increases the fatty acid release rate of coconut oil, quickly provides energy, and can be used as an energy supplement after exercise.

[0127] Test Example 5

[0128] The rheological properties of the double emulsions prepared in Examples 10-12 and the emulsions prepared in Comparative Examples 1-3 were measured using a rheometer equipped with a parallel plate fixture with a diameter of 40 mm, an experimental temperature of 25°C, and a gap of 1 mm. The viscosity curves were obtained at 25°C and a shear rate of 0.1 to 20 / s. The results are shown in FIG. Figure 4 As shown, from Figure 4 It can be seen that, compared with Comparative Examples 1-3, the anthocyanins in Examples 10-11 of the present invention significantly reduce the viscosity of the emulsion.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins, characterized in that: The specific steps include: S1, mixing and heating coconut oil and a lipophilic emulsifier to obtain an oil phase; S2, adding anthocyanidins and sucrose to the citric acid solution to obtain an aqueous phase; S3, adding the water phase to the oil phase, high-speed shearing, and homogenization to obtain a W1 / O type single emulsion encapsulating the water-soluble functional factors; S4, adding maltodextrin and starch into water, heating and gelling, and obtaining a starch-based aqueous phase W2; S5. Slowly add the starch-based aqueous phase W2 to the W1 / O type single emulsion, mix evenly, and let stand to obtain a W1 / O / W2 type starch-based double emulsion encapsulating water-soluble functional factors, that is, a coconut oil / starch double emulsion encapsulating water-soluble anthocyanins.

2. The method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins as claimed in claim 1, characterized in that: In step S1, the mass content of coconut oil in the oil phase is 92%-98%, and the mass content of lipophilic emulsifier is 2%-8%; the temperature of the mixed heating is 80-90° C., and the time is 10-20 minutes.

3. A method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins as claimed in claim 2, characterized in that: The lipophilic emulsifier is polyglycerol ricinoleate or Tween 20.

4. The method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins as claimed in claim 1, characterized in that: In step S2, the anthocyanin is acai berry anthocyanin, and its mass content in the aqueous phase is 1% to 2%; the mass content of sucrose in the aqueous phase is 3% to 4%.

5. The method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins as claimed in claim 1, characterized in that: In step S2, the concentration of the citric acid solution is 0.02-0.1 mol / L, and the pH is 3.6-3.

8.

6. The method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins as claimed in claim 1, characterized in that: In step S3, the mass ratio of the water phase to the oil phase is (1:4) to (4:1); the rotation speed of the high-speed shear is 10000 to 12000 rpm, and the time is 10 to 20 min; the pressure of the homogenization is 5 to 10 MPa, and the time is 3 to 5 min.

7. The method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins as claimed in claim 1, characterized in that: In step S4, the starch content in the starch-based aqueous phase W2 is 3% to 10% w / v; the mass ratio of maltodextrin to starch is (3:1) to (1:3).

8. The method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins as claimed in claim 7, characterized in that: The starch is any one of tapioca starch, potato starch or pea starch.

9. The method for preparing a coconut oil / starch double emulsion for embedding water-soluble anthocyanidins as claimed in claim 1, characterized in that: In step S5, the mass ratio of the starch-based aqueous phase W2 to the W1 / O type single emulsion is (1:4) to (4:1).

10. A coconut oil / starch double emulsion for embedding water-soluble anthocyanidins, prepared by the preparation method according to any one of claims 1 to 9.

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