Green plum pectin-polyphenol composite gel prepared by ultrasound and application of green plum pectin-polyphenol composite gel in intestinal antioxidation

Abstract

The invention discloses a green plum pectin-polyphenol composite gel prepared by ultrasound and an application of the green plum pectin-polyphenol composite gel in intestinal antioxidation. The method comprises the following steps: mixing green plum pectin and green plum polyphenol extract according to a mass ratio of (10: 1)-(2: 1), dissolving in water to form a mixed solution, treating for 2-15 minutes under ultrasonic waves with the power of 100-500W and the frequency of 20-40kHz, and inducing to form a three-dimensional gel network. According to the method, the pectin-polyphenol composite gel is constructed in a green and efficient manner by utilizing an ultrasonic technology without a chemical cross-linking agent. The gel has pH responsiveness, the polyphenol release rate in simulated gastric juice is low (2 hours per, 30%), the polyphenol release rate in simulated intestinal juice is high (4 hours per gt, 70%), polyphenol can be delivered to the intestinal tract in a targeted mode, and the oxidative stress of the intestinal tract is remarkably relieved. Cell and animal experiments show that the gel can effectively improve the survival rate of intestinal cells in an oxidative stress state, enhance the activity of antioxidant enzyme and reduce the level of inflammatory factors. The invention has wide application prospects in the fields of functional food, health care products and medicines.

Description

Technical Field

[0001] This invention belongs to the field of functional food processing and biomaterials technology, specifically relating to a method for preparing a novel pectin-polyphenol composite gel, and its application in the preparation of functional foods, health products or drugs for relieving intestinal oxidative stress. Background Technology

[0002] Oxidative stress is one of the core contributing factors to many intestinal diseases, such as inflammatory bowel disease and colon cancer. Dietary intake of antioxidants is an effective strategy for alleviating intestinal oxidative stress. However, most oral polyphenolic antioxidants have low bioavailability under the action of gastric acid and digestive enzymes, making it difficult for them to effectively reach and act on the intestinal tract.

[0003] Pectin is an excellent gel matrix and delivery carrier, but the gel networks formed by traditional ionic crosslinking or thermo-induced gelation are relatively dense, which may lead to premature release of contents in the small intestine, and its loading rate and protective capacity for polyphenols are limited. Ultrasound technology, as a physical modification method, has been shown to alter the structure and properties of macromolecules. However, to date, no research has utilized ultrasound technology to precisely induce the formation of a novel composite gel network with intestinal-targeted release characteristics from plum pectin and the polyphenols (such as chlorogenic acid and protocatechuic acid) abundant in plums. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing plum pectin-polyphenol composite gel using ultrasound induction. This method is simple, green, and efficient. The resulting composite gel possesses a unique microstructure and pH responsiveness, effectively protecting polyphenols from damage in the upper digestive tract and targeting their delivery to the intestines. There, polyphenols are released in the intestinal environment, exhibiting excellent antioxidant functions. Technical solution

[0005] To achieve the above objectives, the present invention adopts the following technical solution: 1. A method for preparing plum pectin-polyphenol composite gel by ultrasonication, characterized by comprising the following steps: 2. Solution preparation: Dissolve the plum pectin in water to prepare a pectin solution with a mass concentration of 1% to 5%.

[0006] 3. Polyphenol mixing: Add plum polyphenol extract to the pectin solution to make the mass ratio of polyphenols to pectin 1:10~1:2, and stir evenly.

[0007] 4. Ultrasonic treatment: The mixed solution is treated with ultrasound. The key ultrasonic parameters are: power 100~500 W, frequency 20~40 kHz, treatment time 2~15 min, and pulse mode can be selected (e.g., 2 seconds of operation followed by 1 second of interval).

[0008] 5. Gel formation: After ultrasonic treatment, the plum pectin-polyphenol composite gel can be obtained by standing or centrifuging at low speed.

[0009] The plum pectin-polyphenol composite gel prepared according to the above method is characterized by the formation of a three-dimensional network structure within it, composed of pectin chains and polyphenols through non-covalent interactions (hydrogen bonds and hydrophobic interactions). Scanning electron microscopy shows that its pore size is 50-500 nm, which is superior to that of traditional gels. In simulated gastric juice (pH 2.0-3.0), the polyphenol release rate is less than 30% within 2 hours, while in simulated intestinal juice (pH 6.8-7.4), it can release polyphenols rapidly, with a cumulative release rate exceeding 70% within 4 hours. Figure 1 ).

[0010] The application of the plum pectin-polyphenol composite gel in the preparation of functional foods, health products or drugs for preventing and / or alleviating intestinal oxidative stress.

[0011] Beneficial effects

[0012] Compared with the prior art, the outstanding advantages of the present invention are: Green and efficient: Utilizing physical field ultrasound technology, no chemical cross-linking agents are required, and the process is gentle and environmentally friendly.

[0013] Novel structure: Ultrasonic cavitation and mechanical effects induce a looser and more uniform "pectin-polyphenol" synergistic gel network, which significantly improves the encapsulation rate and protection of polyphenols.

[0014] Intelligent targeting: This gel has excellent pH responsiveness, enabling precise delivery of "gastric protection and intestinal release", which greatly improves the bioavailability of polyphenols in the intestinal tract.

[0015] Clearly defined functions: Cellular experiments (such as the Caco-2 / H2O2 oxidative stress model) and animal experiments (such as the DSS-induced mouse colitis model) have confirmed that the composite gel prepared in this invention can significantly improve the survival rate of intestinal cells, reduce intracellular ROS levels, enhance the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and effectively alleviate intestinal oxidative damage and inflammation. Figure 2 ). Attached Figure Description

[0016] Figure 1 The cumulative release curves of polyphenols in simulated gastrointestinal fluid for the composite gel of the present invention and the comparative example (unhybridized group).

[0017] Figure 2 The protective effect of the composite gel of this invention on H2O2-induced oxidative stress model of Caco-2 cells (comparison of cell survival rate). Detailed Implementation

[0018] The terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end" used in the application text to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings. They are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] Example 1: Figure 1 Figure 2 As shown: (1) Prepare a 2% (w / v) solution of plum pectin.

[0021] (2) Add the plum polyphenol extract at a pectin to polyphenol mass ratio of 5:1 and stir magnetically for 30 min to mix it evenly.

[0022] (3) The mixed solution was treated with 400W, 28 kHz ultrasound for 5 min (pulse mode: 2 s on, 1 s off).

[0023] (4) The treated solution was left to stand at 4℃ for 2 h to form a stable composite hydrogel.

[0024] (5) Results: The gel showed an encapsulation rate of 92.5% for polyphenols. The release rate was 22% in simulated gastric juice after 2 hours and 85% in simulated intestinal juice after 4 hours. In the Caco-2 cell oxidative stress model, the cell survival rate of the gel-treated group increased from 55% to 88% compared with the oxidative damage group.

[0025] Example 2

[0026] (1) Prepare a 4% (w / v) solution of plum pectin.

[0027] (2) Add plum polyphenol extract at a pectin to polyphenol mass ratio of 8:1 and stir magnetically for 30 min.

[0028] (3) The mixed solution was treated with 250W, 40kHz ultrasound for 10 min (continuous mode).

[0029] (4) The treated solution was centrifuged at low speed (3000 rpm, 5 min) to obtain a concentrated gel.

[0030] (5) Effects: The encapsulation rate of polyphenols in this gel is 89.3%. The release rate is 25% in simulated gastric juice after 2 hours and 78% in simulated intestinal juice after 4 hours. This gel can be used to prepare oral capsules or tablets into health products.

[0031] Example 3

[0032] (1) Prepare a 1% (w / v) solution of plum pectin.

[0033] (2) Add plum polyphenol extract at a pectin to polyphenol mass ratio of 10:1 and stir magnetically for 30 min.

[0034] (3) Use 500W, 20kHz ultrasound to treat the mixed solution for 2min (pulse mode: 5s on, 2s off).

[0035] (4) The treated solution was left to stand overnight at 4°C to form a gel.

[0036] (5) Effects: The gel has an encapsulation rate of 85.0% for polyphenols. The release rate is 28% in simulated gastric juice after 2 hours and 72% in simulated intestinal juice after 4 hours. The gel has a soft texture and is suitable for making oral liquid.

[0037] Example 4

[0038] (1) Prepare a 5% (w / v) solution of plum pectin.

[0039] (2) Add plum polyphenol extract at a pectin to polyphenol mass ratio of 2:1 and stir magnetically for 30 min.

[0040] (3) The mixed solution was treated with 100 W, 40 kHz ultrasound for 15 min (continuous mode).

[0041] (4) The treated solution was left to stand at 4°C for 2 h to form a high-strength composite gel.

[0042] (5) Effects: The gel has an encapsulation rate of 95.2% for polyphenols. The release rate is 18% in simulated gastric juice after 2 hours and 90% in simulated intestinal juice after 4 hours. The gel has high strength and is suitable as a gel matrix for functional foods.

[0043] Example 5

[0044] (1) Prepare a 3% (w / v) solution of plum pectin.

[0045] (2) Add plum polyphenol extract at a pectin to polyphenol mass ratio of 4:1 and stir magnetically for 30 min.

[0046] (3) The mixed solution was treated with 300 W, 25 kHz ultrasound for 8 min (pulse mode: 3s on, 1s off).

[0047] (4) The treated solution was left to stand at 4°C for 2 h to form a gel.

[0048] (5) Effects: The gel has an encapsulation rate of 91.8% for polyphenols. The release rate is 20% in simulated gastric juice after 2 hours and 82% in simulated intestinal juice after 4 hours. Animal experiments show that gavage administration of this gel can significantly alleviate the disease activity index of DSS colitis mice, reduce the content of malondialdehyde (MDA) in colon tissue, and increase the activity of SOD and GSH-Px.

[0049] Comparative Example The procedure was the same as in Example 1, but without ultrasonic treatment; only mechanical stirring was performed. The resulting mixture formed an unstable gel structure after standing, with an encapsulation rate of only 65%, and the polyphenol release rate exceeded 60% within 2 hours in simulated gastric fluid, failing to achieve intestinal targeting function.

[0050] Green and efficient: Utilizing physical field ultrasound technology, no chemical cross-linking agents are required, and the process is gentle and environmentally friendly.

[0051] Novel structure: Ultrasonic cavitation and mechanical effects induce a looser and more uniform "pectin-polyphenol" synergistic gel network, which significantly improves the encapsulation rate and protection of polyphenols.

[0052] Intelligent targeting: This gel has excellent pH responsiveness, enabling precise delivery of "gastric protection and intestinal release", which greatly improves the bioavailability of polyphenols in the intestinal tract.

[0053] Clearly defined functions: Cellular experiments (such as the Caco-2 / H2O2 oxidative stress model) and animal experiments (such as the DSS-induced mouse colitis model) have confirmed that the composite gel prepared in this invention can significantly improve the survival rate of intestinal cells, reduce intracellular ROS levels, enhance the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and effectively alleviate intestinal oxidative damage and inflammation. Figure 2 ).

[0054] The above embodiments are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

[0055] All parts not covered in this invention are the same as or can be implemented using existing technologies.

Claims

1. A method of ultrasonically preparing a green plum pectin-polyphenol composite gel, characterized by, The method comprises the following steps: Dissolving green plum pectin in water to prepare a pectin solution with a mass concentration of 1%-5%; Adding green plum polyphenol extract to the pectin solution to make the mass ratio of green plum polyphenol to green plum pectin 1:10-1:2, and stirring uniformly to obtain a mixed solution; Performing ultrasonic treatment on the mixed solution, with an ultrasonic power of 100-500 W, a frequency of 20-40 kHz, and a treatment time of 2-15 min; After the ultrasonic treatment, standing or centrifugation is performed to obtain the green plum pectin-polyphenol composite gel.

2. The method of claim 1, wherein, The ultrasonic treatment is performed in a pulse mode, with a pulse working time of 2-5 seconds and an intermittent time of 1-3 seconds.

3. A green plum pectin-polyphenol complex gel prepared by the method of claim 1 or 2, characterized in that, The composite gel has a three-dimensional network structure, and the polyphenol release rate in simulated gastric juice (pH=2.0-3.0) within 2 hours is less than 30%, and the cumulative polyphenol release rate in simulated intestinal juice (pH=6.8-7.4) within 4 hours is higher than 70%.

4. Use of the green plum pectin-polyphenol composite gel according to claim 3 in the preparation of a product for preventing and / or relieving intestinal oxidative stress.

5. Use according to claim 4, characterized in that, The product is a functional food, a health product or a medicine.

6. Use according to claim 4, characterized in that, The intestinal oxidative stress is related to inflammatory bowel disease, colitis or intestinal barrier damage.

7. Use according to claim 4, characterized in that, The composite gel relieves intestinal oxidative stress by enhancing the antioxidant enzyme activity of intestinal cells, reducing the intracellular reactive oxygen species level and inhibiting the expression of inflammatory factors.

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