Hydrogel composite anthocyanin base material and preparation method thereof

Abstract

The invention discloses a preparation method of a hydrogel composite anthocyanin base material, which comprises the following steps: mixing a blueberry anthocyanin solution and a Chinese wolfberry anthocyanin solution according to a certain proportion, mixing the mixture with a uniform glue solution of gellan gum, and shearing to obtain hydrogel-composite anthocyanin. The problem that the embedding effect of a single wall material is poor is solved, and the embedding steps are simplified. The blueberry-wolfberry composite anthocyanin powder is prepared by introducing wolfberry fat-soluble anthocyanin and adopting a hydrogel method, the retention rate of the blueberry-wolfberry composite anthocyanin powder is improved by 31.87% compared with that of free anthocyanin powder, and the retention rate of anthocyanin in the hydrogel composite anthocyanin prepared by adopting the method disclosed by the invention is up to 90% or above; the hydrogel composite anthocyanin prepared by the invention has better thermal stability, and even if the hydrogel composite anthocyanin is stored for 15 days at 60 DEG C, the retention rate of the anthocyanin can still reach 80% or above.

Description

Technical Field

[0001] The invention relates to the field of food processing, in particular to a hydrogel composite anthocyanin base material and a preparation method thereof. Background Art

[0002] Anthocyanin is a kind of flavonoid compound widely found in nature. It is widely found in berries, dark fruits and vegetables, and grains. It has multiple physiological activities such as anti-oxidation, hypoglycemic, anti-inflammatory, vision protection, tumor prevention, and weight loss. As a safe, edible natural pigment with certain health functions, anthocyanin has broad application prospects in the food, medicine, health care products, cosmetics and other industries. However, the structure of anthocyanin is unstable. Affected by factors such as temperature, light, and pH, the color is easily degraded, resulting in products such as jelly and beverages rich in anthocyanins easily losing their original bright color during processing and storage.

[0003] As a kind of natural macromolecule, polysaccharide is widely used for loading anthocyanins. The colloid has strong hydrophilicity and can form a hydrogel with a three-dimensional network structure to encapsulate anthocyanins to form a stable anthocyanin-hydrogel complex. For example, patent CN 115886255A discloses a high-stability blueberry anthocyanin binary gel tablet and its preparation method. By constructing a polysaccharide-protein binary hydrogel, a stable anthocyanin delivery system is constructed and a tablet product is developed. Patent CN115736241A discloses a method for preparing a nanogel, which maintains the stability of anthocyanins by constructing a protein-derivatized polysaccharide nanogel. Although both methods have improved the stability of anthocyanins to a certain extent, both methods use a composite wall material of protein and polysaccharide, and the embedding rate and retention rate of anthocyanins are low. Patent CN117882865A discloses a method for preparing blueberry anthocyanin microcapsules, using carboxymethyl starch and gellan gum as wall materials to embed anthocyanins. Although the embedding rate of anthocyanins in the microcapsules prepared by this method can reach 92.38%, this method still uses a composite wall material containing two polysaccharides, which is not conducive to increasing the content of anthocyanins in the microcapsules. Patent CN114668146A discloses a starch microgel-anthocyanin transporter and a preparation method thereof. Although this method discloses a starch gel-anthocyanin transporter, and specifically discloses that only carboxymethyl starch is used to embed anthocyanins to ensure the stability of anthocyanins. However, the embedding rate of anthocyanins in the transporter prepared by this method is low, less than 55%.

[0004] Therefore, it is of great significance to study the use of a single wall material to encapsulate anthocyanins and improve the retention rate of anthocyanins. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a hydrogel composite anthocyanin base material and a preparation method thereof, wherein gellan gum is selected as the wall material and a mixture of different anthocyanins is used as the core material to prepare the hydrogel composite anthocyanin base material, so as to solve the problems existing in the prior art such as the large variety of wall materials and the low anthocyanin retention rate.

[0006] In view of the above purpose, the present invention first provides a method for preparing a hydrogel composite anthocyanin base material, which specifically comprises the following steps:

[0007] S1: Preparation of colloidal homogenate: dissolving gellan gum in hot water and subjecting it to shearing treatment to obtain colloidal homogenate;

[0008] S2: Preparation of anthocyanin solution: dissolving blueberry anthocyanin in water and ultrasonically treating the solution to obtain a blueberry anthocyanin solution; dissolving wolfberry anthocyanin in water and ultrasonically treating the solution to obtain a wolfberry anthocyanin solution;

[0009] S3: mixing: mixing the colloidal homogenate obtained in step S1, the blueberry anthocyanin solution obtained in step S2, and the wolfberry anthocyanin solution, and subjecting them to shearing treatment to obtain a hydrogel-complex anthocyanin;

[0010] S4: spray drying: dissolving the hydrogel-complex anthocyanin obtained in S3 in water, mixing evenly and then spray drying to obtain a stabilized hydrogel-complex anthocyanin;

[0011] Wherein, in step S3, the weight ratio of the blueberry anthocyanin solution to the wolfberry anthocyanin solution is 6-18:1-3, preferably 7-12:1, more preferably 7-10:1, and further preferably 9:1.

[0012] In one embodiment of the present invention, the weight ratio of the gellan gum to the hot water in step S1 is 1-3:100-300.

[0013] In one embodiment of the present invention, the temperature of the hot water in step S1 is 80° C., the shearing speed is 8000-12000 rpm, and the shearing time is 1-4 min.

[0014] In one embodiment of the present invention, the weight ratio of blueberry anthocyanins to water in step S2 is 1:100, the ultrasonic power is 80-100 W, and the ultrasonic time is 8-15 min.

[0015] In one embodiment of the present invention, the weight ratio of wolfberry anthocyanins to water in step S2 is 1:100, the ultrasonic power is 80-100 W, and the ultrasonic time is 8-15 min.

[0016] In one embodiment of the present invention, the weight ratio of the colloidal homogenate to the total amount of the blueberry anthocyanin solution and the wolfberry anthocyanin solution in step S3 is 3-9:1-2.

[0017] In one embodiment of the present invention, the rotation speed during shearing in step S3 is 8000-10000 rpm, and the shearing time is 1-4 min.

[0018] In one embodiment of the present invention, the weight ratio of the hydrogel-complex anthocyanin to water in step S4 is 1:1-10.

[0019] In one embodiment of the present invention, during the spray drying in step S4, the inlet temperature and the outlet temperature are both 130°C to 150°C, and the flow rate is 3 mL / min. -1 , the pressure is 0.1MPa~0.2MPa.

[0020] The invention also discloses a stabilized hydrogel-complex anthocyanin prepared according to the method.

[0021] The invention also discloses an application of the stabilized hydrogel-complex anthocyanin in food.

[0022] Beneficial effects:

[0023] 1. The present invention mixes fat-soluble wolfberry anthocyanins with blueberry anthocyanins and uses gellan gum as a wall material to embed them, thereby overcoming the poor embedding effect of a single wall material and simplifying the embedding steps.

[0024] 2. The present invention introduces wolfberry fat-soluble anthocyanins and adopts a hydrogel method to prepare blueberry-wolfberry composite anthocyanin powder, which increases the retention rate by 31.87% compared with free anthocyanin powder. The retention rate of anthocyanins in the hydrogel composite anthocyanin prepared by the method of the present invention is as high as over 90%.

[0025] 3. The hydrogel composite anthocyanin prepared by the method of the present invention has good thermal stability. Even if stored at 60°C for 15 days, the retention rate of the anthocyanin can still reach more than 80%. The hydrogel anthocyanin proposed by the present invention has the characteristics of high retention rate, high stability and convenient preparation. DETAILED DESCRIPTION

[0026] 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.

[0027] Test method for anthocyanin retention rate:

[0028] Anthocyanin content detection method: Take 0.1g of blueberry-wolfberry composite anthocyanin powder sample (M1) before spray drying in a 10mL centrifuge tube, dilute to 10mL with anhydrous ethanol, ultrasonically extract for 10min, centrifuge for 10min, take the supernatant, dilute 5 times with 5% phosphoric acid water, filter with 0.22μm water phase, and use liquid chromatography to detect the anthocyanin content. The detection method of blueberry-wolfberry embedded composite anthocyanin powder (M2) after spray drying is the same as above;

[0029] The liquid chromatography condition parameters are as follows: the chromatographic column is a C18 liquid chromatography column, the mobile phase is acetonitrile (solution A) and 1% formic acid aqueous solution (solution A), the column temperature is 40°C, the flow rate is 1mL / min, the injection volume is 10uL, and the elution conditions are shown in Table 1 below:

[0030] Table 1 Gradient elution program

[0031]

[0032] The retention rate is calculated as follows:

[0033] Retention rate % = (M2 / M1) × 100%

[0034] Where: M1—anthocyanin content in the sample before spray drying, in mg;

[0035] M2—Anthocyanin content in the sample after spray drying, in mg.

[0036] Anthocyanin thermal stability test method:

[0037] Free anthocyanins or hydrogel-complex anthocyanins were placed in an oven at 60°C, and the retention rate of anthocyanins after storage for 3, 6, 9, 12 and 15 days was tested.

[0038] Example 1

[0039] A method for preparing a hydrogel composite anthocyanin stabilization base material, the specific steps are as follows:

[0040] S1: Preparation of colloidal homogenate: Weigh 1 part of gellan gum, dissolve it in 100 parts of 80°C pure water solution, and shear it at a speed of 10000 rpm for 2 minutes to obtain a colloidal homogenate;

[0041] S2: Preparation of anthocyanins: Weigh 1 part of blueberry anthocyanins, dissolve it in 100 parts of pure water, and perform ultrasonic treatment at a power of 100 W for 10 minutes to obtain a blueberry anthocyanin solution; weigh 1 part of wolfberry anthocyanins, dissolve it in 100 parts of pure water, and perform ultrasonic treatment for 10 minutes to obtain a wolfberry anthocyanin solution;

[0042] S3: Mixing: Take 40 parts of colloidal homogenate, add 9 parts of blueberry anthocyanin solution and 1 part of wolfberry anthocyanin solution, and shear at a speed of 10000 rpm for 2 minutes to obtain hydrogel-complex anthocyanin;

[0043] S4: Spray drying: Add 50 parts of pure water to S3, mix well and then spray dry (inlet / outlet temperature 130°C, flow rate 3mL / min -1 , pressure is 0.1MPa) to obtain a stabilized hydrogel-complex anthocyanin.

[0044] Comparative Example 1

[0045] The difference between Comparative Example 1 and Example 1 is that gellan gum is replaced by pectin.

[0046] Comparative Example 2

[0047] The difference between Comparative Example 2 and Example 1 is that gellan gum is replaced by carrageenan.

[0048] Comparative Example 3

[0049] The difference between Comparative Example 3 and Example 1 is that the gellan gum is replaced by locust bean gum.

[0050] Comparative Example 4

[0051] The difference between Comparative Example 4 and Example 1 is that the gellan gum is replaced by xanthan gum.

[0052] Comparative Example 5

[0053] The difference between Comparative Example 5 and Example 1 is that the gellan gum is replaced by curdlan gum.

[0054] Comparative Example 6

[0055] The difference between Comparative Example 6 and Example 1 is that the gellan gum is replaced by guar gum.

[0056] Comparative Example 7

[0057] The difference between Comparative Example 7 and Example 1 is that gellan gum is replaced by konjac gum.

[0058] Comparative Example 8

[0059] The difference between Comparative Example 8 and Example 1 is that gellan gum is replaced by hydroxypropyl distarch phosphate.

[0060] Comparative Example 9

[0061] The difference between Comparative Example 9 and Example 1 is that the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is different. In Comparative Example 9, the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is 1:1.

[0062] Comparative Example 10

[0063] The difference between Comparative Example 10 and Example 1 is that the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is different. In Comparative Example 10, the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is 4:1.

[0064] Comparative Example 11

[0065] The difference between Comparative Example 11 and Example 1 is that the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is different. In Comparative Example 11, the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is 1:4.

[0066] Comparative Example 12

[0067] The difference between Comparative Example 12 and Example 1 is that the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is different. In Comparative Example 12, the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is 1:9.

[0068] Comparative Example 13

[0069] The difference between Comparative Example 13 and Example 1 is that the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is different. In Comparative Example 13, the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is 1:0.

[0070] Comparative Example 14

[0071] The difference between Comparative Example 14 and Example 1 is that the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is different. In Comparative Example 14, the weight ratio of blueberry anthocyanins to wolfberry anthocyanins is 0:1.

[0072] The retention rate of the hydrogel-complex anthocyanins obtained in Example 1 and Comparative Examples 1 to 8 was tested, and the results are shown in Table 2. It can be seen from Table 2 that when preparing the hydrogel-complex anthocyanins, the type of wall material used has a great influence on the retention rate of anthocyanins. Among them, when gellan gum is used as the wall material, the retention rate of anthocyanins in the prepared hydrogel composite anthocyanins is the highest, which can be as high as 90.25%. Although guar gum, locust bean gum and pectin can also obtain an anthocyanin retention rate of more than 85% as wall materials, the retention rate of anthocyanins is lower than that of gellan gum, which is less than 90%.

[0073] Table 2 Retention rate of anthocyanins in the hydrogel-composite anthocyanins obtained in Example 1 and Comparative Examples 1 to 8

[0074] example Wall material type Anthocyanin retention rate Example 1 Gellan Gum 90.25％ Comparative Example 1 Pectin 85.00％ Comparative Example 2 Carrageenan 80.25％ Comparative Example 3 Locust Bean Gum 86.75％ Comparative Example 4 Xanthan gum 83.50％ Comparative Example 5 Curdlan 70.50％ Comparative Example 6 Guar gum 87.25％ Comparative Example 7 Konjac Gum 74％ Comparative Example 8 Hydroxypropyl distarch phosphate 80.25％

[0075] Table 3 shows the effect of the anthocyanin compounding ratio on the anthocyanin retention rate. It can be seen from Table 3 that when the mass ratio of blueberry anthocyanin to wolfberry anthocyanin is 9:1, the retention rate of anthocyanin in the prepared hydrogel composite anthocyanin is the highest, up to 95.22%, and as the proportion of blueberry anthocyanin decreases, the anthocyanin retention rate shows a downward trend. When the proportion of blueberry anthocyanin in the total anthocyanin is less than 20%, the retention rate of anthocyanin in the hydrogel composite anthocyanin is much lower than that of hydrogel blueberry anthocyanin and hydrogel wolfberry anthocyanin, indicating that the compounding ratio of anthocyanin has a great influence on the retention rate of anthocyanin.

[0076] Table 3 Retention rate of anthocyanins in the hydrogel-composite anthocyanins obtained in Example 1 and Comparative Examples 9 to 14

[0077] Serial number Blueberry anthocyanins: wolfberry anthocyanins Retention Rate Example 1 9:1 90.25％ Comparative Example 9 1:1 44.17％ Comparative Example 10 4:1 79.17％ Comparative Example 11 1:4 11.00％ Comparative Example 12 1:9 7.14％ Comparative Example 13 1:0 42.74％ Comparative Example 14 0:1 55.27％

[0078] Table 4 Anthocyanin stability test

[0079]

[0080] Table 4 shows the changes in anthocyanin retention rates of the hydrogel composite anthocyanins prepared in Example 1 and free anthocyanins (a mixture of blueberry anthocyanins and wolfberry anthocyanins in a weight ratio of 9:1) after storage at 60°C. It can be seen from Table 4 that the stability of free anthocyanins at high temperatures is poor. After only 3 days of storage at 60°C, the anthocyanin retention rate has dropped to 80.26%. The anthocyanins in the hydrogel composite anthocyanins prepared by the method of the present invention have good thermal stability. Even after being stored at 60°C for 15 days, the anthocyanin retention rate can still reach more than 80%.

[0081] 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 hydrogel composite anthocyanin base, characterized in that: The following steps are involved: S1: Preparation of colloidal homogenate: dissolving gellan gum in hot water and subjecting it to shearing treatment to obtain colloidal homogenate; S2: Preparation of anthocyanin solution: dissolving blueberry anthocyanin in water and ultrasonically treating the solution to obtain a blueberry anthocyanin solution; dissolving wolfberry anthocyanin in water and ultrasonically treating the solution to obtain a wolfberry anthocyanin solution; S3: mixing: mixing the colloidal homogenate obtained in step S1, the blueberry anthocyanin solution obtained in step S2, and the wolfberry anthocyanin solution, and subjecting them to shearing treatment to obtain a hydrogel-complex anthocyanin; S4: spray drying: dissolving the hydrogel-complex anthocyanin obtained in S3 in water, mixing evenly and then spray drying to obtain a stabilized hydrogel-complex anthocyanin; Wherein, in step S3, the weight ratio of the blueberry anthocyanin solution to the wolfberry anthocyanin solution is 6 to 12:

1.

2. The preparation method according to claim 1, characterized in that: In step S1, the weight ratio of the gellan gum to the hot water is 1-3:100-300.

3. The preparation method according to claim 1, characterized in that: In step S1, the temperature of the hot water is 80° C., the shearing speed is 8000-12000 rpm, and the shearing time is 1-4 min.

4. The preparation method according to claim 1, characterized in that: In step S2, the weight ratio of blueberry anthocyanin to water is 1:100, the ultrasonic power is 80-100 W, and the ultrasonic time is 8-15 min. The weight ratio of wolfberry anthocyanin to water is 1:100, the ultrasonic power is 80-100 W, and the ultrasonic time is 8-15 min.

5. The preparation method according to claim 1, characterized in that: In step S3, the weight ratio of the colloidal homogenate to the total amount of the blueberry anthocyanin solution and the wolfberry anthocyanin solution is 3-9:1-2.

6. The preparation method according to claim 1, characterized in that: The rotation speed during shearing in step S3 is 8000-10000 rpm, and the shearing time is 1-4 min.

7. The preparation method according to claim 1, characterized in that: The weight ratio of the hydrogel-complex anthocyanin to water in step S4 is 1:1-10.

8. The preparation method according to claim 1, characterized in that: In step S4, during spray drying, the inlet temperature and outlet temperature are both 130°C to 150°C, and the flow rate is 3 mL / min. -1 , the pressure is 0.1MPa~0.2MPa.

9. The stabilized hydrogel-complex anthocyanin prepared according to the method of any one of claims 1 to 8.

10. Use of the stabilized hydrogel-complex anthocyanin according to claim 9 in food.

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