Method for preparing water-soluble curcumin by microencapsulation

Abstract

The present invention relates to the technical field of curcumin microcapsule technology, and proposes a method for preparing water-soluble curcumin by microencapsulation, which includes the following steps: S1. Preparation of aqueous phase: Mix modified maltodextrin, chitosan, curcumin and water to obtain an aqueous phase; S2. Preparation of oil phase: Stir medium-chain triglycerides at 50-60 °C to obtain an oil phase; S3. Emulsification: After shearing the aqueous phase, add the oil phase to the aqueous phase and continue shearing to obtain an emulsion; S4. Spray drying: Spray dry the emulsion to obtain curcumin microcapsules; the modified maltodextrin is obtained by modifying maltodextrin with palmitic acid and sorbic acid. Through the above technical solution, the problems of low embedding rate and poor stability of curcumin microcapsules in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of curcumin microcapsules, and specifically, to a method for preparing water-soluble curcumin by microencapsulation. Background Art

[0002] Curcumin is a natural active ingredient extracted from the rhizomes of Zingiberaceae plants such as Curcuma longa. It is an acidic polyphenolic substance with an unsaturated aliphatic and aromatic group as the main chain.

[0003] Curcumin is a natural pigment permitted to be used in China's food additive standards, and its dyeing power is greater than that of other natural pigments and synthetic tartrazine, etc. Curcumin also has many physiological effects, such as a series of biological and pharmacological activities such as antioxidant, lipid-lowering, anti-atherosclerotic, anti-inflammatory, anti-aging, and anti-tumor, and has very little toxic and side effects on the human body, with broad application prospects. However, due to its poor physicochemical stability and low in vivo bioavailability, a large dosage is often required to reach the effective dose, which greatly limits the application and popularization of curcumin. Microencapsulation of curcumin can solve the problems in its application such as poor water solubility and instability to a certain extent, but there are problems of low embedding rate and poor stability of curcumin microcapsules in the prior art. Summary of the Invention

[0004] The present invention provides a method for preparing water-soluble curcumin by microencapsulation, which solves the problems of low embedding rate and poor stability of curcumin microcapsules in the related art.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing water-soluble curcumin by microencapsulation, comprising the following steps:

[0007] S1. Preparation of the aqueous phase: Mix modified maltodextrin, chitosan, curcumin and water to obtain the aqueous phase;

[0008] S2. Preparation of the oil phase: Stir medium-chain triglycerides at 50 - 60 °C to obtain the oil phase;

[0009] S3. Emulsification: After shearing the aqueous phase, add the oil phase to the aqueous phase and continue shearing to obtain an emulsion;

[0010] S4. Spray drying: Spray dry the emulsion to obtain curcumin microcapsules;

[0011] The modified maltodextrin is obtained by modifying maltodextrin with palmitic acid and sorbic acid.

[0012] As a further technical solution, in the preparation of the aqueous phase in S1, at 50 - 60 °C, mix 40 - 50 parts of modified maltodextrin, 25 - 30 parts of gum arabic, 10 - 15 parts of curcumin and 80 - 90 parts of water to obtain the aqueous phase.

[0013] As a further technical solution, the mass ratio of the oil phase to the water phase in S3 is 1:8 - 9.

[0014] As a further technical solution, the shear rate in S3 is 8200 - 8350 rmp, and the shear time is 10 - 20 min.

[0015] As a further technical solution, the inlet air temperature for spray drying in S4 is 170 - 180 °C, and the outlet air temperature is 95 - 100 °C.

[0016] As a further technical solution, the preparation method of the modified maltodextrin in S1 includes the following steps:

[0017] A1. At 45 - 50 °C, add maltodextrin to the sodium carbonate solution and mix to obtain mixture I;

[0018] A2. Add palmitic acid and sorbic acid to mixture I, mix, and react at 45 - 50 °C to obtain mixture II;

[0019] A3. After adjusting the pH of mixture II to 8 - 8.5, wash, filter, and dry to obtain the modified maltodextrin.

[0020] As a further technical solution, the mass ratio of the maltodextrin, palmitic acid, and sorbic acid is 15 - 20:3:1.

[0021] As a further technical solution, in A1, the sodium carbonate solution has a mass fraction of 4%; the mass ratio of the maltodextrin to the sodium carbonate solution is 2 - 2.5:8.

[0022] As a further technical solution, in A2, when reacting, add sodium hydroxide solution to control the pH value of the reaction system to 8.2 - 8.6.

[0023] As a further technical solution, the concentration of the sodium hydroxide solution is 0.2 - 0.5 moL / L.

[0024] The working principle and beneficial effects of the present invention are as follows:

[0025] 1. The present invention uses a macromolecular material with good solubility, emulsifying property, and film-forming property as the wall material for microencapsulating curcumin, and prepares curcumin microcapsules, which improves the solubility and stability of curcumin.

[0026] 2. The present invention modifies maltodextrin, introduces branches on the hydroxyl groups of maltodextrin, which increases the steric hindrance between branches, so that the molecules are not easily polymerized and coagulated, and can improve the embedding rate of curcumin microcapsules.

[0027] 3. The present invention modifies maltodextrin with palmitic acid and sorbic acid. Introducing palmitic acid onto the hydroxyl groups of maltodextrin can endow maltodextrin with amphiphilic properties, along with emulsifying and thickening effects, improving the emulsifying property and stability of curcumin microcapsules; the addition of sorbic acid not only increases the encapsulation rate of curcumin microcapsules but also enhances their stability. Detailed Embodiment

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of the present invention.

[0029] Example 1

[0030] A method for preparing water-soluble curcumin by microencapsulation includes the following steps:

[0031] S1. At 55°C, 45 parts of modified maltodextrin, 27 parts of gum arabic, 14 parts of curcumin, and 85 parts of water are mixed to obtain an aqueous phase.

[0032] S2. 20 parts of medium-chain triglycerides are stirred at 55°C to obtain an oil phase.

[0033] S3. The aqueous phase is sheared for 15 min, then continue shearing and add the oil phase into the aqueous phase. After adding the oil phase, continue shearing for 10 min to obtain an emulsion; the shearing speed is 8300 rmp in both cases.

[0034] S4. The emulsion is spray-dried to obtain curcumin microencapsulated; the inlet air temperature for spray drying is 175°C, the outlet air temperature is 97°C, and the peristaltic pump flow rate is 34 rmp.

[0035] The preparation method of the modified maltodextrin includes the following steps:

[0036] A1. At 50°C, 40 g of maltodextrin is added to 128 g of a 4% sodium carbonate solution and mixed to obtain mixture I.

[0037] A2. 6 g of palmitic acid and 2 g of sorbic acid are added to mixture I and mixed. Then, the reaction is carried out at 50°C for 5 h to obtain mixture II; during the reaction, a 0.5 moL / L sodium hydroxide solution is added to control the pH of the reaction system to 8.4 - 8.6.

[0038] A3. After adding a 0.1 moL / L hydrochloric acid solution to adjust the pH of mixture II to 8.5, it is washed with absolute ethanol, filtered, and vacuum-dried to obtain the modified maltodextrin.

[0039] Example 2

[0040] A method for preparing water-soluble curcumin by microencapsulation, comprising the following steps:

[0041] S1. At 50 °C, 40 parts of modified maltodextrin, 25 parts of gum arabic, 10 parts of curcumin and 80 parts of water are mixed to obtain an aqueous phase; among them, the preparation method of modified maltodextrin is the same as that in Example 1;

[0042] S2. 19 parts of medium-chain triglyceride are stirred at 50 °C to obtain an oil phase;

[0043] S3. After shearing the aqueous phase for 10 min, continue shearing and add the oil phase to the aqueous phase, and continue shearing for 10 min after adding the oil phase to obtain an emulsion; the shearing speed is 8200 rmp;

[0044] S4. The emulsion is spray-dried to obtain curcumin microencapsulated; the inlet air temperature for spray drying is 170 °C, the outlet air temperature is 95 °C, and the peristaltic pump flow rate is 34 rmp.

[0045] Example 3

[0046] A method for preparing water-soluble curcumin by microencapsulation, comprising the following steps:

[0047] S1. At 60 °C, 50 parts of modified maltodextrin, 30 parts of gum arabic, 15 parts of curcumin and 90 parts of water are mixed to obtain an aqueous phase; among them, the preparation method of modified maltodextrin is the same as that in Example 1;

[0048] S2. 20.5 parts of medium-chain triglyceride are stirred at 60 °C to obtain an oil phase;

[0049] S3. After shearing the aqueous phase for 20 min, continue shearing and add the oil phase to the aqueous phase, and continue shearing for 10 min after adding the oil phase to obtain an emulsion; the shearing speed is 8350 rmp;

[0050] S4. The emulsion is spray-dried to obtain curcumin microencapsulated; the inlet air temperature for spray drying is 180 °C, the outlet air temperature is 100 °C, and the peristaltic pump flow rate is 34 rmp.

[0051] Example 4

[0052] A method for preparing water-soluble curcumin by microencapsulation, comprising the following steps:

[0053] S1. At 55 °C, 47 parts of modified maltodextrin, 25 parts of gum arabic, 15 parts of curcumin and 90 parts of water are mixed to obtain an aqueous phase;

[0054] S2. After stirring 20 parts of medium-chain triglycerides at 55 °C, an oil phase is obtained.

[0055] S3. After shearing the aqueous phase for 15 min, continue shearing and add the oil phase to the aqueous phase. After adding the oil phase, continue shearing for 10 min to obtain an emulsion; the shearing speed is 8350 rmp in both cases.

[0056] S4. Spray-dry the emulsion to obtain curcumin encapsulated in microcapsules; the inlet air temperature for spray drying is 180 °C, the outlet air temperature is 100 °C, and the peristaltic pump flow rate is 34 rmp.

[0057] The preparation method of the modified maltodextrin includes the following steps:

[0058] A1. At 47 °C, add 34 g of maltodextrin to 118 g of a 4% sodium carbonate solution and mix to obtain mixture I.

[0059] A2. Add 6 g of palmitic acid and 2 g of sorbic acid to mixture I and mix. React at 47 °C for 4.5 h to obtain mixture II; during the reaction, add a 0.3 moL / L sodium hydroxide solution to control the pH of the reaction system at 8.2 - 8.4.

[0060] A3. Adjust the pH of mixture II to 8 with a 0.1 moL / L hydrochloric acid solution, then wash with absolute ethanol, filter, and vacuum dry to obtain the modified maltodextrin.

[0061] Example 5

[0062] The method for preparing water-soluble curcumin by microencapsulation includes the following steps:

[0063] S1. At 60 °C, mix 40 parts of modified maltodextrin, 25 parts of gum arabic, 15 parts of curcumin, and 90 parts of water to obtain an aqueous phase.

[0064] S2. After stirring 20 parts of medium-chain triglycerides at 55 °C, an oil phase is obtained.

[0065] S3. After shearing the aqueous phase for 15 min, continue shearing and add the oil phase to the aqueous phase. After adding the oil phase, continue shearing for 10 min to obtain an emulsion; the shearing speed is 8200 rmp in both cases.

[0066] S4. Spray-dry the emulsion to obtain curcumin encapsulated in microcapsules; the inlet air temperature for spray drying is 170 °C, the outlet air temperature is 95 °C, and the peristaltic pump flow rate is 34 rmp.

[0067] The preparation method of the modified maltodextrin includes the following steps:

[0068] A1. At 45 °C, add 30 g of maltodextrin to 120 g of a 4% sodium carbonate solution by mass to obtain Mixture I;

[0069] A2. Add 6 g of palmitic acid and 2 g of sorbic acid to Mixture I and mix. Then react at 45 °C for 4 h to obtain Mixture II; during the reaction, add a 0.2 moL / L sodium hydroxide solution to control the pH of the reaction system to be 8.3 - 8.5.

[0070] A3. Adjust the pH of Mixture II to 8 with a 0.1 moL / L hydrochloric acid solution, then wash with absolute ethanol, filter, and vacuum dry to obtain modified maltodextrin.

[0071] Comparative Example 1

[0072] A method for microencapsulating water-soluble curcumin, comprising the following steps:

[0073] S1. At 55 °C, mix 45 parts of maltodextrin, 27 parts of gum arabic, 14 parts of curcumin, and 85 parts of water to obtain an aqueous phase;

[0074] S2. Stir 20 parts of medium-chain triglycerides at 55 °C to obtain an oil phase;

[0075] S3. After shearing the aqueous phase for 15 min, continue shearing and add the oil phase to the aqueous phase. After adding the oil phase, continue shearing for 10 min to obtain an emulsion; the shearing speed is 8300 rmp in both cases;

[0076] S4. Spray-dry the emulsion to obtain curcumin microencapsulated; the inlet temperature for spray drying is 175 °C, the outlet temperature is 97 °C, and the flow rate of the peristaltic pump is 34 rmp.

[0077] Comparative Example 2

[0078] Compared with Example 1, in Comparative Example 2, palmitic acid is replaced with an equal amount of stearic acid, and the others are the same as in Example 1.

[0079] Comparative Example 3

[0080] Compared with Example 1, in Comparative Example 3, sorbic acid is not added, and the others are the same as in Example 1.

[0081] Comparative Example 4

[0082] Compared with Example 1, in Comparative Example 4, palmitic acid is not added, and the others are the same as in Example 1.

[0083] Comparative Example 5

[0084] Compared with Example 1, the difference in Comparative Example 5 is 4 g of palmitic acid and 4 g of sorbic acid.

[0085] Comparative Example 6

[0086] Compared with Example 1, the difference in Comparative Example 6 is 2 g of palmitic acid and 6 g of sorbic acid.

[0087] Comparative Example 7

[0088] Compared with Example 1, the difference in Comparative Example 7 is 7 g of palmitic acid and 1 g of sorbic acid.

[0089] Test Example

[0090] Determine the embedding rate and stability of the curcumin microcapsules prepared in Examples 1-5 and Comparative Examples 1-7.

[0091] Method for determining the embedding rate: Dissolve the curcumin microcapsules in 95% ethanol, extract by ultrasonic for 10 min, determine the total content of curcumin in the microcapsules, then dissolve the unembedded curcumin in 95% ethanol, determine the initial curcumin content, and calculate the embedding rate of the curcumin microcapsules according to the following formula. The measurement results are shown in Table 1:

[0092] Embedding rate = (1 - A0 / A1) × 100%

[0093] Wherein, A1: total content of curcumin in the curcumin microcapsules; A0: initial curcumin content.

[0094] Method for determining the stability: Place the curcumin microcapsules in a thermostatic and humidity-controlled test chamber (40 °C, 75% RH) for accelerated testing, respectively determine the curcumin content in the initial curcumin microcapsules and the curcumin content in the curcumin microcapsules after being placed for 30 d, calculate the curcumin retention rate, and use the curcumin retention rate as the stability evaluation index. The measurement results are shown in Table 1.

[0095] Table 1 Embedding rate and retention rate of curcumin microcapsules prepared in Examples 1-5 and Comparative Examples 1-7

[0096] Entrapment efficiency (%) Retention rate (%) Example 1 92.16 90.78 Example 2 91.79 90.05 Example 3 93.62 92.21 Example 4 91.57 91.60 Example 5 91.21 89.28 Comparative Example 1 75.62 58.56 Comparative Example 2 83.21 83.65 Comparative Example 3 86.27 85.25 Comparative Example 4 87.15 84.85 Comparative Example 5 88.62 86.21 Comparative Example 6 87.93 87.32 Comparative Example 7 88.82 87.19

[0097] Compared with Example 1, the maltodextrin in Comparative Example 1 was not modified. As a result, both the embedding rate and stability of the curcumin microcapsules were lower than those in Example 1, indicating that modifying the maltodextrin in the present invention can improve the embedding rate and stability of the curcumin microcapsules.

[0098] Compared with Example 1, in Comparative Example 2, palmitic acid was replaced with an equal amount of stearic acid. In Comparative Example 3, sorbic acid was not added. In Comparative Example 4, palmitic acid was not added. As a result, the encapsulation rate and stability of the curcumin microcapsules prepared in Comparative Examples 2-4 were lower than those in Example 1. This shows that conventional replacement of palmitic acid will lead to a decrease in the quality of curcumin microcapsules, and also shows that modification of maltodextrin with sorbic acid and palmitic acid can both improve the encapsulation rate and stability of curcumin microcapsules, but the effect is not as good as the co-modification of maltodextrin with sorbic acid and palmitic acid.

[0099] Compared with Example 1, in Comparative Examples 5-7, the ratios of palmitic acid and sorbic acid were changed respectively. As a result, the encapsulation rate and stability of the curcumin microcapsules prepared in Comparative Examples 5-7 were lower than those in Example 1. This shows that when the mass ratio of palmitic acid to sorbic acid is 3:1, the performance of the modified maltodextrin is the best, which improves the encapsulation rate and stability of the curcumin microcapsules.

[0100] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing water-soluble curcumin by microencapsulation, characterized in that, It includes the following steps: S1. Aqueous phase preparation: Mix modified maltodextrin, arabic gum, curcumin and water to obtain an aqueous phase; S2. Oil phase preparation: Stir medium-chain triglycerides at 50 - 60 °C to obtain an oil phase; S3. Emulsification: After shearing the aqueous phase, add the oil phase to the aqueous phase and continue shearing to obtain an emulsion; S4. Spray drying: Spray dry the emulsion to obtain curcumin microcapsules; The modified maltodextrin is obtained by modifying maltodextrin with palmitic acid and sorbic acid; The preparation method of the modified maltodextrin in S1 includes the following steps: A1. At 45 - 50 °C, add maltodextrin to a sodium carbonate solution and mix to obtain mixture I; A2. Add palmitic acid and sorbic acid to mixture I and mix, then react at 45 - 50 °C to obtain mixture II; A3. Adjust the pH of mixture II to 8 - 8.5, then wash, filter and dry to obtain modified maltodextrin; The mass ratio of the maltodextrin, palmitic acid and sorbic acid is 15 - 20:3:

1.

2. The method for preparing water-soluble curcumin by microencapsulation according to claim 1, characterized in that, The preparation of the aqueous phase in S1 is to mix 40 - 50 parts of modified maltodextrin, 25 - 30 parts of arabic gum, 10 - 15 parts of curcumin and 80 - 90 parts of water at 50 - 60 °C to obtain an aqueous phase.

3. The method for preparing water-soluble curcumin by microcapsule embedding according to claim 1, characterized in that, The mass ratio of the oil phase to the aqueous phase in S3 is 1:8 - 9.

4. The method for preparing water-soluble curcumin by microencapsulation according to claim 1, characterized in that, The shear rate in S3 is 8200 - 8350 rmp, and the shear time is 10 - 20 min.

5. The method for preparing water-soluble curcumin by microcapsule embedding according to claim 1, characterized in that, The inlet air temperature of the spray drying in S4 is 170 - 180 °C, and the outlet air temperature is 95 - 100 °C.

6. The method for preparing water-soluble curcumin by microencapsulation according to claim 1, characterized in that, The sodium carbonate solution in A1 has a mass fraction of 4%; the mass ratio of the maltodextrin to the sodium carbonate solution is 2 - 2.5:

8.

7. The method for preparing water-soluble curcumin by microencapsulation according to claim 1, characterized in that, In A2 during the reaction, add a sodium hydroxide solution to control the pH value of the reaction system to 8.2 - 8.

6.

8. The method for preparing water-soluble curcumin by microcapsule embedding according to claim 7, characterized in that, The concentration of the sodium hydroxide solution is 0.2 - 0.5 moL / L.