A method for embedding blueberry anthocyanins

Abstract

The present invention discloses a method for embedding blueberry anthocyanins, using pectin, hydroxypropyl distarch phosphate and maltodextrin as composite wall materials, and embedding anthocyanins in combination with high-pressure homogenization to prepare anthocyanin microcapsules. The present invention crushes the microcapsules into a smaller particle size range through high-pressure homogenization, increases the contact between anthocyanins and the wall material, and combines high-pressure homogenization with freeze-drying embedding technology to give play to their respective advantages and enhance the stability and retention rate of anthocyanins. The anthocyanin microcapsules prepared by the method of the present invention have a high anthocyanin retention rate of up to 94.54%, and the anthocyanin microcapsules have good temperature and light stability.

Description

Technical Field

[0001] The invention belongs to the technical field of anthocyanidin embedding, and particularly relates to a method for embedding blueberry anthocyanidin. Background Art

[0002] Blueberry, also known as lingonberry, is a perennial evergreen shrub of the genus Vaccinium in the Ericaceae family. Blueberry anthocyanins have attracted much attention in recent years due to their well-known health-promoting properties and rich anthocyanin content. Anthocyanins are water-soluble plant pigments that can enhance the color of blueberries, and they also have a variety of physiologically active functions, such as anti-oxidation, promoting rhodopsin resynthesis, improving immunity, anti-cardiovascular disease, and anti-aging.

[0003] Blueberry anthocyanins are widely used in food, natural pigments, cosmetics, pharmaceuticals and other fields, but anthocyanin molecules are extremely unstable and easily degraded, especially sensitive to light, temperature, oxygen, enzyme activity and various storage conditions. During food processing, especially in the presence of oxygen, the stability of anthocyanins decreases with increasing temperature, eventually leading to thermal degradation and producing brown products. It has been reported in the literature that the antioxidant capacity or activity of anthocyanin extracts will change during storage. Therefore, improving the stability of blueberry anthocyanins is an important issue that needs to be addressed.

[0004] At present, the mechanisms for improving the stability of blueberry anthocyanins are mainly cross-linking reactions and microencapsulation methods. There are some defects in cross-linking reactions, such as the difficulty in precise control of the reaction and the lack of understanding of the interaction mechanism in the process of improving stability. Microencapsulation technology can be used to fix and carry bioactive compounds in solid particles (microspheres) or liquid vesicles to protect and stabilize bioactive compounds, which is beneficial for light- and heat-sensitive molecules, such as anthocyanins, to maintain stability and improve their shelf life. At present, the commonly used methods of encapsulation technology are spray drying or vacuum freeze drying. The vacuum freeze drying method is widely used to prepare anthocyanin microcapsules because it can effectively inhibit the changes of anthocyanins in external factors such as high temperature and oxygen, and can better preserve the activity of anthocyanins and their own appearance color. For example, the article "Preparation of Anthocyanin Microcapsules by Vacuum Freeze Drying and Stability Study" uses freeze drying to encapsulate anthocyanins and studies the effects of different wall materials on the encapsulation effect of anthocyanins. The article also discloses that the maximum encapsulation rate can be obtained by using 60g / L hydroxypropyl distarch phosphate for anthocyanin encapsulation, but the maximum encapsulation rate obtained when using this wall material and encapsulation method for encapsulation is only 55.21%, resulting in a low retention rate of anthocyanins. In the article "Preparation and Performance Study of Proanthocyanidin Microcapsules", sodium alginate and carboxymethyl cellulose were used as composite wall materials, and the sharp hole method was used to prepare proanthocyanidin microcapsules in order to improve the stability, antioxidant activity and sustained release performance of proanthocyanidins. However, the particle size of the microcapsules prepared by this method was relatively large (0.82 mm), which limited its application. Summary of the invention

[0005] In view of the above-mentioned problems, the purpose of the present invention is to provide a method for encapsulating blueberry anthocyanins, using pectin, hydroxypropyl distarch phosphate and maltodextrin as composite wall materials and combining high-pressure homogenization treatment to encapsulate anthocyanins, so as to solve the problems of low anthocyanin encapsulation rate and large size of prepared microcapsules in the prior art.

[0006] To achieve the above-mentioned purpose, the present invention provides a method for encapsulating blueberry anthocyanins, comprising the following steps:

[0007] (1) Core material preparation: blueberry anthocyanin powder and purified water are mixed to prepare a core material solution;

[0008] (2) wall material preparation: pectin, hydroxypropyl distarch phosphate and maltodextrin are used as wall materials, mixed with water, heated to make the wall materials swell in the water and stirred to prepare a wall material solution;

[0009] (3) Mixing the core material and the wall material: After the wall material solution in step (2) is cooled to room temperature, the core material solution obtained in step (1) is slowly added to the wall material solution, and after shear mixing, high pressure homogenization is performed, and freeze drying is performed to prepare anthocyanin microcapsules;

[0010] Wherein, in the wall material described in step (2), the mass ratio of pectin, hydroxypropyl distarch phosphate and maltodextrin is 2-4:1-2:1-2.

[0011] In one embodiment of the present invention, in the wall material described in step (2), the mass ratio of pectin, hydroxypropyl distarch phosphate and maltodextrin is 2:1:1.

[0012] In one embodiment of the present invention, the concentration of the core material solution in step (1) is 0.5-5 g / L.

[0013] In one embodiment of the present invention, the concentration of the wall material solution in step (2) is 50-70 g / L.

[0014] In one embodiment of the present invention, in step (2), the heating temperature is 80-90° C. and the heating time is 30-60 min.

[0015] In one embodiment of the present invention, in step (2), the stirring speed is 800 rpm.

[0016] In one embodiment of the present invention, in step (3), the volume ratio of the core material solution to the wall material solution is 1:2-5.

[0017] In one embodiment of the present invention, in step (3), the speed of shear mixing is (7-9)×10 3rpm, and the shearing time was 5 min.

[0018] In one embodiment of the present invention, in step (3), the high-pressure homogenization treatment is carried out by using a flow emulsifying homogenizer, the homogenization pressure is 200 to 500 bar, and the homogenization rate is 20 to 30 L / h.

[0019] In one embodiment of the present invention, in step (3), the freeze drying is vacuum freeze drying. During freeze drying, the vacuum pressure is pumped to below 10 kPa, the freezing temperature is -40 to -60°C, and the freeze drying time is 36 to 72 hours.

[0020] The present invention also provides blueberry anthocyanin microcapsules prepared according to the method.

[0021] The present invention also provides an application of the blueberry anthocyanin microcapsule in the fields of food, medicine and cosmetics.

[0022] Beneficial effects of the present invention:

[0023] (1) The present invention uses pectin, hydroxypropyl distarch phosphate and maltodextrin as mixed wall materials and embeds anthocyanins, thereby significantly improving the embedding rate of anthocyanins. Under the optimal ratio and parameter conditions, the embedding rate of anthocyanins in anthocyanin microcapsules prepared by the method of the present invention can be as high as 94.54%.

[0024] (2) The present invention crushes the microcapsules into a smaller particle size range through high-pressure homogenization treatment, thereby increasing the contact between anthocyanins and the wall material. The combination of high-pressure homogenization treatment and freeze-drying embedding technology can give full play to their respective advantages and enhance the stability and retention rate of anthocyanins. The homogenization treatment can significantly reduce the particle size of the microcapsules and enhance their dispersibility, which makes the application of anthocyanins in the fields of food, medicine and cosmetics more extensive and convenient. The freeze-drying process can maintain the original structure of anthocyanins and avoid their destruction due to drying.

[0025] (3) The blueberry anthocyanin encapsulation method of the present invention has the characteristics of high encapsulation rate, high thermal stability and light stability, and high intestinal release rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the SEM image of unencapsulated anthocyanin;

[0027] Figure 2 This is a SEM scanning electron microscope image of anthocyanin microcapsules prepared in Example 1;

[0028] Figure 3 This is the effect of homogenization pressure on anthocyanin retention rate;

[0029] Figure 4It is a comparison chart of the temperature stability of unembedded anthocyanin (unembedded) and anthocyanin microcapsules (lyophilized sample) prepared in Example 1;

[0030] Figure 5 It is a comparison chart of the light stability of unembedded anthocyanin (unembedded) and anthocyanin microcapsules (lyophilized sample) prepared in Example 1;

[0031] Figure 6 The changes of anthocyanin content during the simulated digestion process for unencapsulated anthocyanin (black curve) and anthocyanin microcapsules prepared in Example 1 (red curve). DETAILED DESCRIPTION

[0032] The present invention is further explained below in conjunction with specific examples. It should be noted that the following examples are only used for explaining the present invention, but not for limiting the scope of application of the present invention. In addition, after reading the content explained in the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to the present application.

[0033] The anthocyanin content test was carried out according to the method in NY / T 2640-2014. During the test, the mobile phase in 6.4.1 was replaced with methanol, and other conditions remained unchanged.

[0034] Stability Characterization:

[0035] Temperature stability: The freeze-dried anthocyanin powder was placed at 40°C and 60°C for 1 hour, and the anthocyanin content was determined by HPLC;

[0036] Light stability: freeze-dried anthocyanins and common anthocyanins were placed in light (natural light) and sealed (sealed aluminum foil bag) respectively, and the anthocyanin content was measured on the 7th day;

[0037] pH stability: The samples were placed in solutions with pH values ​​of 3, 5, 7, 9, and 11, and their anthocyanin content was determined. The components and dosages of solutions with different pH values ​​are shown in the table below:

[0038]

[0039]

[0040] In vitro digestion simulation experiment: 2g of anthocyanin sample was placed in 0.9% saline, the pH value was adjusted to 2-3, 0.16g of pepsin was added, and a constant temperature water bath shaker was used for simulated digestion at 37°C for 2h, and samples were taken every 30min. 0.5mol / L of sodium bicarbonate was added to adjust the solution pH to 9-11, 12mL of 2mg / mL of trypsin and 6mL of 12mg / mL of bile salt were added, and a constant temperature water bath shaker was used for simulated digestion at 37°C for 2h, and samples were taken every 30min, and then the anthocyanin content of each sample was determined.

[0041] Example 1

[0042] A method for embedding blueberry anthocyanins comprises the following steps:

[0043] (1) Core material preparation: blueberry anthocyanin powder and purified water were mixed to prepare a core material solution with a concentration of 1.67 g / L;

[0044] (2) wall material preparation: pectin, hydroxypropyl distarch phosphate and maltodextrin were used as wall materials, mixed with water, heated at 80° C. for 45 min, so that the wall materials swelled in water, and stirred at 800 rpm to prepare a wall material solution. The concentration of the wall material solution was 60 g / L.

[0045] (3) Mixing the core material and the wall material: After the wall material solution in step (2) is cooled to room temperature, the core material solution obtained in step (1) is slowly added to the wall material solution, at which the volume ratio of the core material solution to the wall material solution is 1:3. After shear mixing at a speed of 9000 rpm for 5 min, a high-pressure homogenization treatment is performed at a homogenization pressure of 350 bar and a homogenization rate of 30 L / h. Anthocyanin microcapsules are prepared by freeze drying;

[0046] Wherein, in the wall material described in step (2), the mass ratio of pectin, hydroxypropyl distarch phosphate and maltodextrin is 2:1:1.

[0047] Example 2

[0048] The difference between Example 2 and Example 1 is that in step (3), the pressure of high-pressure homogenization is different. The pressure of high-pressure homogenization in Example 2 is 200 bar.

[0049] Example 3

[0050] The difference between Example 2 and Example 1 is that in step (3), the pressure of high-pressure homogenization is different. The pressure of high-pressure homogenization in Example 3 is 300 bar.

[0051] Example 4

[0052] The difference between Example 4 and Example 1 is that in step (3), the pressure of high-pressure homogenization is different. The pressure of high-pressure homogenization in Example 4 is 400 bar.

[0053] Example 5

[0054] The difference between Example 5 and Example 1 is that in step (3), the pressure of high-pressure homogenization is different. The pressure of high-pressure homogenization in Example 5 is 500 bar.

[0055] Comparative Example 1

[0056] The difference between Comparative Example 1 and Example 1 is that in step (2), the mass ratio of pectin, hydroxypropyl distarch phosphate and maltodextrin is 1:1:1.

[0057] Comparative Example 2

[0058] The difference between Comparative Example 2 and Example 1 is that in step (2), the mass ratio of pectin, hydroxypropyl distarch phosphate and maltodextrin is 1:2:1.

[0059] Comparative Example 3

[0060] The difference between Comparative Example 3 and Example 1 is that in step (2), the mass ratio of pectin, hydroxypropyl distarch phosphate and maltodextrin is 1:1:2.

[0061] Comparative Example 4

[0062] The difference between Comparative Example 4 and Example 1 is that in step (2), the mass ratio of pectin, hydroxypropyl distarch phosphate and maltodextrin is 1:4:1.

[0063] Comparative Example 5

[0064] The difference between Comparative Example 5 and Example 1 is that in step (2), only hydroxypropyl distarch phosphate is used as the wall material.

[0065] Comparative Example 6

[0066] The difference between Comparative Example 6 and Example 1 is that in step (3), the pressure of high-pressure homogenization is different. The pressure of high-pressure homogenization in Comparative Example 6 is 100 bar.

[0067] Figure 1 and Figure 2 The SEM images of the unencapsulated blueberry anthocyanidins and the blueberry anthocyanidins microcapsules prepared in Example 1 are shown in FIG. Figure 1 It can be seen that the unencapsulated blueberry anthocyanidins are in fragments, while after being encapsulated by the method of the present invention, the blueberry anthocyanidins form a plurality of spherical or quasi-spherical microcapsules, indicating that the anthocyanidins are successfully encapsulated.

[0068] Table 1 shows the embedding rate data of anthocyanin in anthocyanin microcapsules prepared in Example 1 and Comparative Examples 1 to 5. It can be seen from Table 1 that the embedding rate of anthocyanin in anthocyanin microcapsules prepared in Example 1 is the highest, reaching 93.62%, while the embedding rates of anthocyanin in Comparative Examples 1 to 4 are all relatively low, and are lower than the data of Comparative Example 5 using a single hydroxypropyl distarch phosphate as the wall material for embedding, indicating that the embedding rate of anthocyanin cannot necessarily be improved by using a plurality of materials for composite as wall materials. When a plurality of materials are composited, the ratio of each material has an important influence on the embedding rate of anthocyanin.

[0069] Table 1 Theoretical value, measured value and embedding rate of anthocyanin in anthocyanin microcapsules prepared in Example 1 and Comparative Examples 1 to 5

[0070]

[0071]

[0072] Table 2 shows the retention rate of anthocyanin in anthocyanin microcapsules prepared in Examples 1 to 5 and Comparative Example 6. It can be seen from Table 2 that with the increase of homogenization pressure, the retention rate shows an upward trend. Figure 3 . At a pressure of 100 bar, the retention rate of anthocyanins in anthocyanin microcapsules was 80.61%, while at a pressure of 500 bar, the retention rate of anthocyanins rose to 94.52%, an increase of about 14 percentage points. This upward trend is gradual. Each time the pressure increases by 100, the increase in the retention rate gradually decreases, but it still maintains an overall increase. The increase in homogenization pressure helps to improve the embedding efficiency, allowing more target substances to be effectively embedded in the carrier. This may be because the material particles are more closely combined together, reducing the loss during subsequent processing, thereby improving the retention rate.

[0073] Table 2 Comparison of retention rates of anthocyanins in anthocyanin microcapsules prepared in Examples 1 to 5 and Comparative Example 6

[0074] example Retention Rate Example 1 93.62％ Example 2 84.4％ Example 3 87.47％ Example 4 91.63％ Example 5 94.54％ Comparative Example 6 80.61％

[0075] Figure 4 The loss rate of anthocyanin after placing the unembedded anthocyanin (unembedded) and the anthocyanin microcapsules (lyophilized sample) prepared in Example 1 in 40°C and 60°C environments for 1 hour is given. Figure 4It can be seen that the loss rate of unencapsulated anthocyanidins at 40°C is relatively large, reaching 20%, while the use of the method of the present invention to embed anthocyanidins helps to greatly reduce the loss rate of anthocyanidins. The loss rate of anthocyanidin microcapsules prepared in Example 1 at 60°C is only 2.5%, which is much lower than the loss rate of unencapsulated anthocyanidins. This shows that the embedded sample significantly improves the temperature stability of the sample by forming a protective layer. This shows that this embedding technology is an effective means of protection, which can reduce the loss of samples caused by temperature changes during storage and transportation.

[0076] Figure 5 : is a comparison chart of the photostability of unencapsulated anthocyanin (unencapsulated) and anthocyanin microcapsules (lyophilized sample) prepared in Example 1. Figure 5 As shown, the unembedded sample suffered serious loss of anthocyanins under light conditions due to lack of protection, while the embedded sample improved the stability of anthocyanins.

[0077] Figure 6 The comparison of the changes in anthocyanin content between the unembedded sample and the anthocyanin microcapsules prepared in Example 1 during the simulated digestion process is given. Figure 6 It can be seen that the anthocyanin content of both samples decreased during simulated digestion, but the decreasing trend was different. The anthocyanin content of the embedded sample decreased more slowly during the digestion process, which played a better protective role for the anthocyanin, allowing the anthocyanin to be slowly released during gastric digestion, playing a sustained release role. The anthocyanin content of the unembedded sample decreased faster, indicating that it was more vulnerable to damage in the digestive environment.

[0078] 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 encapsulating blueberry anthocyanins, characterized in that: The following steps are involved: (1) Core material preparation: blueberry anthocyanin powder and purified water are mixed to prepare a core material solution; (2) wall material preparation: pectin, hydroxypropyl distarch phosphate and maltodextrin are used as wall materials, mixed with water, heated to make the wall materials swell in the water and stirred to prepare a wall material solution; (3) Mixing the core material and the wall material: After the wall material solution in step (2) is cooled to room temperature, the core material solution obtained in step (1) is slowly added to the wall material solution, and after shear mixing, high pressure homogenization is performed, and freeze drying is performed to prepare anthocyanin microcapsules; Wherein, in the wall material described in step (2), the mass ratio of pectin, hydroxypropyl distarch phosphate and maltodextrin is 2-4:1-2:1-2.

2. The embedding method according to claim 1, characterized in that: The concentration of the core material solution described in step (1) is 0.5 to 5 g / L.

3. The embedding method according to claim 1, characterized in that: The concentration of the wall material solution described in step (2) is 50-70 g / L.

4. The embedding method according to claim 1, characterized in that: In step (2), the heating temperature is 80-90° C., the heating time is 30-60 min, and the stirring speed is 800 rpm.

5. The embedding method according to claim 1, characterized in that: In step (3), the volume ratio of the core material solution to the wall material solution is 1:2-5.

6. The embedding method according to claim 1, characterized in that: In step (3), the speed of shear mixing is (7-9)×10 3 rpm, and the shearing time was 5 min.

7. The embedding method according to claim 1, characterized in that: In step (3), the high-pressure homogenization treatment is carried out by using a flow emulsifying homogenizer, the homogenization pressure is 200 to 500 bar, and the homogenization rate is 20 to 30 L / h.

8. The embedding method according to claim 1, characterized in that: In step (3), the freeze drying is vacuum freeze drying. During freeze drying, the vacuum pressure is pumped to below 10 kPa, the freezing temperature is -40 to -60°C, and the freeze drying time is 36 to 72 hours.

9. Blueberry anthocyanin microcapsules prepared according to the method according to any one of claims 1 to 8.

10. Use of the blueberry anthocyanin microcapsules according to claim 9 in the fields of food, medicine and cosmetics.

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