Hydrogel for improving satiety and preparation method and application thereof

Abstract

The invention discloses hydrogel for improving satiety as well as a preparation method and application of the hydrogel, and relates to the technical field of polymer gel preparation. The preparation method of the hydrogel for improving satiety comprises the following steps: mixing a cellulose derivative and water, adding a crosslinking aid, and fully and uniformly mixing to obtain a first solution; adding pectin into the first solution, fully and uniformly mixing, and adjusting the pH value to 7.5-8.0 to obtain a second solution; carrying out physical cross-linking on the second solution under ultrasonic treatment to obtain a first cross-linked substance; adding pectin into the first cross-linked substance, and continuously stirring to obtain gel; and removing moisture to obtain the hydrogel for improving satiety. The prepared hydrogel is good in mechanical performance and high in water absorption capacity, the satiety is improved through water absorption expansion, the good weight reduction effect is achieved, and meanwhile the hydrogel has the good effect of adjusting intestinal flora.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer gel preparation, and particularly relates to a hydrogel for enhancing satiety, a preparation method thereof, and an application thereof. Background Art

[0002] A gel is a semi-solid substance formed by a network structure absorbing liquid, and has high water retention and volume expansion characteristics. If used for satiety purposes, it can expand in the stomach after ingestion, occupying space to reduce hunger.

[0003] Currently, the preparation methods of carboxymethyl cellulose-based hydrogels include: ion crosslinking method, radiation crosslinking method, freeze-thaw method, free radical polymerization method, interpenetrating network polymerization method, etc. The ion crosslinking method utilizes a large number of carboxyl groups contained in carboxymethyl cellulose molecules, which can generate electrostatic interaction with divalent or trivalent metal cations, thereby forming a three-dimensional network structure; the radiation crosslinking method refers to the formation of chemical bonds between the main chains of linear molecules after radiation. This method avoids the addition of crosslinking agents and has no impurity doping, not only reducing the complexity of the reaction and the generation of by-products, but also ensuring the non-toxicity of the obtained hydrogel; the freeze-thaw method refers to the state of molecular chains in a polymer solution staying at a certain moment after freezing. Through physical actions such as van der Waals forces and hydrogen bonds, chain entanglements are formed between adjacent molecular chains and are tightly combined in a certain micro-region to become "entanglement points". The free radical polymerization method is prepared by a polymerization reaction with continuously growing free radicals; the interpenetrating network polymerization method is to blend two or more polymers, and the polymer chains interpenetrate and entangle with each other, and there is only a physical action between them.

[0004] Currently, the mainstream preparation of hydrogels is mostly through chemical crosslinking. Hydrogels prepared by pure physical crosslinking have more advantages in terms of safety, biocompatibility, preparation cost, etc., and at the same time have dynamic reversibility. The gel state can be regulated by external stimuli (such as temperature, pH, etc.), providing a design basis for intelligent responsive materials. However, hydrogels prepared by physical crosslinking are weaker in terms of strength and stability.

[0005] Chinese Patent CN119409994A discloses a fat-absorbing hydrogel, its preparation method and application. After mixing a polysaccharide gum with water, wet ultrafine grinding is carried out to obtain an ultrafine polysaccharide gum aqueous solution. High-shear mixing is used to uniformly infiltrate the polysaccharide gum into the interior of cellulose or its derivatives to form micelles. Microwave vacuum drying is used to promote the formation of a honeycomb structure in the micelles. Finally, ultrapure water sprayed by high-pressure atomization is sprayed onto the honeycombed micelles and dried to obtain the fat-absorbing hydrogel. The hydrogel prepared by this method has a water absorption multiple of more than 100 times, a storage modulus of more than 1350 Pa, and can efficiently absorb fat, and has broad development prospects in the field of weight loss drugs or foods. However, this method requires steps such as wet ultrafine grinding, high-pressure atomization spraying, and microwave vacuum drying. The overall production process is relatively complex, has high requirements for equipment and production conditions, and is difficult to achieve large-scale production. Therefore, on the basis of ensuring the performance of the gel, this method still needs to be further optimized. Summary of the Invention

[0006] The object of the present invention is to provide a hydrogel for enhancing satiety, its preparation method and application. By adding specific auxiliaries and crosslinking in two steps, the prepared hydrogel has good mechanical properties and strong water absorption ability, and improves satiety by water absorption and swelling to achieve good weight loss effects. At the same time, this hydrogel also has a good effect of regulating the intestinal flora.

[0007] To achieve the above object of the invention, the technical solution of the present invention is as follows: On the one hand, the present invention provides a preparation method of a hydrogel for enhancing satiety, comprising the following steps: (1) Mix cellulose derivatives and water, add a crosslinking auxiliary, and mix well to obtain a first solution; in the first solution, the mass content of cellulose derivatives is 0.5%-3%, and the crosslinking auxiliary is CaCl 2 and ZnSO 4 in a combination of mass ratio 1:1-4, and the mass content of the crosslinking auxiliary is 0.1%-1%; (2) Add pectin to the first solution obtained in step (1), mix well, and adjust the pH to 7.5-8.0 to obtain a second solution; (3) Physically crosslink the second solution obtained in step (2) under ultrasonic treatment to obtain a first crosslinked product; (4) Add pectin to the first crosslinked product obtained in step (3), and continuously stir to obtain a gel; (5) Remove the moisture from the gel obtained in step (4) to obtain the hydrogel for enhancing satiety.

[0008] Preferably, in step (1), the cellulose derivative is selected from at least one of sodium carboxymethyl cellulose (CMC), methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC), and hydroxyethyl methyl cellulose (HEMC), and more preferably sodium carboxymethyl cellulose.

[0009] Preferably, in step (1), the molecular weight of the cellulose derivative is 100,000 - 200,000.

[0010] Preferably, in step (1), in the first solution, the mass content of the cellulose derivative is 0.5% - 2%, and more preferably 1%.

[0011] Preferably, in step (1), in the first solution, the crosslinking aid is CaCl 2 and ZnSO 4 in a combination of mass ratio 1:2.

[0012] Preferably, in step (1), in the first solution, the mass content of the crosslinking aid is 0.25%.

[0013] Preferably, in step (2), the mass ratio of the pectin to the cellulose derivative in step (1) is 7 - 9:0.5 - 1.5, and more preferably 8:1.

[0014] Preferably, in step (2), the degree of esterification of the pectin is 58% - 62%.

[0015] Preferably, in step (2), the pH is adjusted using sodium citrate.

[0016] Preferably, in step (2), the pH is adjusted to 7.5.

[0017] Preferably, in step (3), the conditions for ultrasonic treatment are: ultrasonic power 500W - 1200W, ultrasonic time 5min - 40min; more preferably, the conditions for ultrasonic treatment are: ultrasonic power 1000W, ultrasonic time 20min.

[0018] Preferably, in step (4), the mass ratio of the pectin to the cellulose derivative in step (1) is 7 - 9:0.5 - 2, and more preferably 8:1.

[0019] Preferably, in step (4), the conditions for continuous stirring are: stirring temperature 10℃ - 25℃, stirring speed 100r / min - 800r / min, stirring time 1h - 3h. More preferably: stirring temperature 20℃, stirring speed 500r / min, stirring time 2h.

[0020] In step (5), the moisture removal can be carried out by any method that does not deteriorate the performance of the gel, and the gel obtained in step (4) is separated from the solution. Examples of such methods include, but are not limited to, evaporation drying, freeze drying, precipitation, centrifugation, spray drying, critical point drying, etc. As a specific example of the present invention, evaporation drying is adopted.

[0021] Preferably, in step (5), the conditions for evaporation drying are: drying at 25°C - 50°C for 24 h - 72 h, and more preferably: drying at 40°C for 48 h.

[0022] Preferably, in step (5), before the moisture removal, the following steps are further included: adding water to the gel obtained in step (4) until saturation, washing 2 - 3 times with water, and filtering with an ultrafiltration membrane.

[0023] Preferably, the preparation method further includes a step: pulverization.

[0024] Further, the pulverization step is: pulverizing the hydrogel obtained in step (5) to 20 - 50 meshes.

[0025] As an example of the present invention, the preparation method specifically includes the following steps: (1) Adding sodium carboxymethylcellulose to water, stirring until fully dissolved, adding a crosslinking aid while stirring, and fully mixing to obtain a first solution; in the first solution, the mass content of sodium carboxymethylcellulose is 0.5% - 3%, and the crosslinking aid is CaCl 2 and ZnSO 4 in a combination of mass ratio 1:1 - 4, and the mass content of the crosslinking aid is 0.1% - 1%; (2) Adding pectin to the first solution obtained in step (1), the mass ratio of the pectin to the sodium carboxymethylcellulose in step (1) is 7 - 9:0.5 - 1.5, after fully mixing, adjusting the pH to 7.5 - 8.0 to obtain a second solution; (3) Putting the second solution obtained in step (2) into an ultrasonic instrument, and performing physical crosslinking under ultrasonic treatment, the ultrasonic power is 500 W - 1200 W, and the ultrasonic time is 5 min - 40 min to obtain a first crosslinked product; (4) Taking out the first crosslinked product obtained in step (3), adding pectin, the mass ratio of the pectin to the sodium carboxymethylcellulose in step (1) is 7 - 9:0.5 - 2, continuously stirring, the stirring temperature is 10°C - 25°C, the stirring speed is 100 r / min - 800 r / min, and the stirring time is 1 h - 3 h to obtain a gel; (5) Add water to the gel obtained in step (4) until saturated, wash it with water 2 - 3 times, filter it through a 10KDa ultrafiltration membrane to remove the additives, dry it at 25°C - 50°C for 24h - 72h, and then crush it to 20 - 50 mesh to obtain the satiety - enhancing hydrogel.

[0026] On the other hand, the present invention provides a satiety - enhancing hydrogel prepared by the above - mentioned preparation method.

[0027] On the other hand, the present invention provides the application of the above - mentioned satiety - enhancing hydrogel in the preparation of weight - loss products.

[0028] Preferably, the weight - loss product is a food, a drug or a health product, and more preferably a food.

[0029] On the other hand, the present invention provides the application of the above - mentioned satiety - enhancing hydrogel in the preparation of products with the function of regulating intestinal flora.

[0030] Preferably, the product with the function of regulating intestinal flora is a food, a drug or a health product, and more preferably a food.

[0031] The satiety - enhancing hydrogel of the present invention can be ingested alone, or formed into a mixture with a liquid or dry food, or as a component of a food or an edible matrix, in a dry, partially swollen or fully swollen state. Preferably, it is ingested in a substantially anhydrous state, that is, in a state with about 10% or less water by weight. When ingested in combination with water in a substantially anhydrous form, the hydrogel can swell in the stomach. After transferring to the small intestine, it will absorb the surrounding liquid and continue to swell. Then, the swollen hydrogel enters the large intestine, degrades in the large intestine, releases the absorbed water, and then is excreted from the body.

[0032] When used for the preparation of a drug, the satiety - enhancing hydrogel of the present invention can be formulated into a capsule, a sachet, a tablet or a suspension for oral administration.

[0033] The beneficial effects of the present invention are as follows: (1) By adjusting to a specific pH and synergistically using CaCl 2 , ZnSO 4 as additives to increase the ionic cross - link points, affect the stretching state of the molecular chains, promote physical entanglement, improve the mechanical properties of the gel, and solve the drawbacks of poor mechanical properties of physically cross - linked gels, which in turn affect storage, transportation and fluidity in the body. (2) In the present invention, two-step crosslinking is adopted. In the first step, ultrasonic treatment is carried out. Through the acoustic cavitation effect, honeycomb-shaped pores are formed inside the crosslinked structure. In the second step, pectin is added for secondary crosslinking. During the whole process, cavitation bubbles can serve as templates to induce the formation of pores inside the gel, and then through the two-step physical crosslinking of cellulose derivatives and pectin under appropriate conditions, the pores formed by the bubbles are fixed to form a honeycomb-shaped porous structure. The obtained gel can significantly improve the water absorption capacity. When applied in weight loss products, it can significantly improve the weight loss effect.

[0034] (3) The hydrogel prepared by the present invention can absorb water and swell, improve satiety, and achieve good weight loss effects. At the same time, this hydrogel also has a good effect on regulating the intestinal flora. Description of the Drawings

[0035] Figure 1 It is the SEM image of the hydrogel prepared in Example 3 of the present invention.

[0036] Figure 2 It is a schematic diagram of the body weight changes of mice in the blank group, model group, and the administration group of the example; in the figure, when the model group is compared with the blank group, P < 0.05, P < 0.01; when the experimental group is compared with the model group, #P < 0.05, ##P < 0.01.

[0037] Figure 3 It is a schematic diagram of the body weight changes of mice in the administration group of Example 3 and the administration group of the comparative example; in the figure, when the comparative example group is compared with the group of Example 3, P < 0.05, P < 0.01. Detailed Embodiments

[0038] The following non-limiting examples can enable those of ordinary skill in the art to more comprehensively understand the present invention, but do not limit the present invention in any way. The following content is only an exemplary illustration of the scope claimed by the present invention. Those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and they should also fall within the scope claimed by the present invention.

[0039] For the numerical ranges in the present invention, it should be understood that unless otherwise specified in the present invention, any value at both ends of each numerical range and any value between the two ends can be selected. For example, the numerical range "0.5% - 3%" includes 0.5% and 3% and any real number between them, such as 0.5%, 0.51%, 0.511%, 0.6%, 0.65%, 0.7%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, etc.

[0040] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs.

[0041] The present invention will be further described below by way of specific embodiments. All kinds of chemical reagents used in the embodiments of the present invention are obtained through conventional commercial channels unless otherwise specified. Unless otherwise specified, the contents described below are mass contents. Unless otherwise specified, it is understood to be carried out at room temperature.

[0042] In the following embodiments, the sodium carboxymethylcellulose, hydroxyethyl cellulose, pectin, CaCl 2 , ZnSO 4 , sodium citrate, and citric acid are preferably food-grade or pharmaceutical-grade materials. For example, sodium carboxymethylcellulose, hydroxyethyl cellulose, pectin, CaCl 2 , ZnSO 4 , sodium citrate, and citric acid are all used as food additives and pharmaceutical excipients.

[0043] In the following embodiments, the average molecular weight of sodium carboxymethylcellulose is 100,000 - 200,000, and the degree of esterification of pectin is 58% - 62%. As a specific example, the sodium carboxymethylcellulose in the following embodiments is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with the product number C104983 and an average molecular weight of 100,000; hydroxyethyl cellulose is purchased from Shanghai Titan Technology Co., Ltd., with the product number 89157Q and an average molecular weight of 200,000. Pectin is purchased from Dangshan Haisheng Pectin Co., Ltd., with the product number HSC105 and a degree of esterification of 58%; the product number is HSC151B and the degree of esterification is 62%. The ultrasonic instrument used is an ultrasonic cell disruptor (Shanghai Yetuo YT-1800E), with a frequency range of 19.5KHz - 20.5KHz.

[0044] Example 1 (1) Add sodium carboxymethylcellulose to water, stir until fully dissolved, and add a crosslinking aid while stirring, and mix well to obtain a first solution; in the first solution, the mass content of sodium carboxymethylcellulose is 0.5%, and the crosslinking aid is CaCl 2 and ZnSO 4 in a combination of mass ratio 1:1, and the mass content of the crosslinking aid is 0.1%; (2) Add pectin (degree of esterification 58%) to the first solution obtained in step (1), the mass ratio of the pectin to the sodium carboxymethylcellulose in step (1) is 7:1.5, after mixing well, use sodium citrate to adjust the pH to 7.5 to obtain a second solution; (3) Put the second solution obtained in step (2) into an ultrasonic instrument, and carry out physical crosslinking under ultrasonic treatment, with an ultrasonic power of 500W and an ultrasonic time of 40min to obtain a first crosslinked product; (4) Take out the first cross-linked product obtained in step (3), add pectin (esterification degree is 58%), the mass ratio of the pectin to the sodium carboxymethyl cellulose in step (1) is 7:2, continuously stir, the stirring temperature is 25 °C, the stirring speed is 100 r / min, and the stirring time is 3 h to obtain a gel; (5) Add water to the gel obtained in step (4) until saturated, wash 3 times with water, filter with a 10 KDa ultrafiltration membrane to remove the auxiliary agent, dry at 25 °C for 72 h, and then pulverize to 20 mesh - 50 mesh to obtain the product.

[0045] Example 2 (1) Add hydroxyethyl cellulose to water, stir until fully dissolved, add the cross-linking auxiliary agent while stirring, and mix well to obtain the first solution; in the first solution, the mass content of hydroxyethyl cellulose is 3%, and the cross-linking auxiliary agent is CaCl 2 and ZnSO 4 in a combination of mass ratio 1:4, and the mass content of the cross-linking auxiliary agent is 1%; (2) Add pectin (esterification degree is 62%) to the first solution obtained in step (1), the mass ratio of the pectin to the hydroxyethyl cellulose in step (1) is 9:0.5, mix well, and use sodium citrate to adjust the pH to 8.0 to obtain the second solution; (3) Put the second solution obtained in step (2) into an ultrasonic instrument, and perform physical cross-linking under ultrasonic treatment, the ultrasonic power is 1200 W, and the ultrasonic time is 5 min to obtain the first cross-linked product; (4) Take out the first cross-linked product obtained in step (3), add pectin (esterification degree is 62%), the mass ratio of the pectin to the hydroxyethyl cellulose in step (1) is 9:0.5, continuously stir, the stirring temperature is 10 °C, the stirring speed is 800 r / min, and the stirring time is 1 h to obtain a gel; (5) Add water to the gel obtained in step (4) until saturated, wash 3 times with water, filter with a 10 KDa ultrafiltration membrane to remove the auxiliary agent, dry at 50 °C for 24 h, and then pulverize to 20 mesh - 50 mesh to obtain the product.

[0046] Example 3 (1) Add sodium carboxymethyl cellulose to water, stir until fully dissolved, add the cross-linking auxiliary agent while stirring, and mix well to obtain the first solution; in the first solution, the mass content of sodium carboxymethyl cellulose is 1%, and the cross-linking auxiliary agent is CaCl 2 and ZnSO 4 in a combination of mass ratio 1:2, and the mass content of the cross-linking auxiliary agent is 0.25%; (2) To the first solution obtained in step (1), add pectin (esterification degree is 58%), the mass ratio of the pectin to the sodium carboxymethylcellulose in step (1) is 8:1. After fully mixing, adjust the pH to 7.5 with sodium citrate to obtain a second solution; (3) Put the second solution obtained in step (2) into an ultrasonic instrument and carry out physical cross-linking under ultrasonic treatment. The ultrasonic power is 1000 W and the ultrasonic time is 20 min to obtain a first cross-linked product; (4) Take out the first cross-linked product obtained in step (3), add pectin (esterification degree is 58%), the mass ratio of the pectin to the sodium carboxymethylcellulose in step (1) is 8:1, continuously stir, the stirring temperature is 20 °C, the stirring speed is 500 r / min, and the stirring time is 2 h to obtain a gel; (5) Add water to the gel obtained in step (4) until saturated, wash it twice with water, filter it with a 10 KDa ultrafiltration membrane to remove the auxiliary agent, dry it at 45 °C for 48 h, and then crush it to 20 mesh - 50 mesh to obtain the product. The SEM diagram is as Figure 1 .

[0047] Comparative Example 1 (1) Add sodium carboxymethylcellulose to water, stir until fully dissolved, add a cross-linking auxiliary agent while stirring, and fully mix to obtain a first solution; in the first solution, the mass content of sodium carboxymethylcellulose is 1%, and the cross-linking auxiliary agent is CaCl 2 and ZnSO 4 in a combination of mass ratio 1:2, and the mass content of the cross-linking auxiliary agent is 0.25%; (2) To the first solution obtained in step (1), add pectin, the mass ratio of the pectin to the sodium carboxymethylcellulose in step (1) is 8:2. After fully mixing, adjust the pH to 7.5 with sodium citrate to obtain a second solution; (3) Put the second solution obtained in step (2) into an ultrasonic instrument and carry out physical cross-linking under ultrasonic treatment. The ultrasonic power is 1000 W and the ultrasonic time is 20 min to obtain a first cross-linked product; (4) Take out the first cross-linked product obtained in step (3), continue to stir, the stirring temperature is 20 °C, the stirring speed is 500 r / min, and the stirring time is 2 h to obtain a gel; (5) Add water to the gel obtained in step (4) until saturated, wash it twice with water, filter it with a 10 KDa ultrafiltration membrane to remove the auxiliary agent, dry it at 45 °C for 48 h, and then crush it to 20 mesh - 50 mesh to obtain the product.

[0048] Compared with Example 3, in this method, all the required amount of pectin is added at one time for cross-linking.

[0049] Comparative Example 2 (1) Add sodium carboxymethylcellulose to water, stir until fully dissolved, and add a crosslinking aid while stirring. Mix well to obtain a first solution. In the first solution, the mass content of sodium carboxymethylcellulose is 1%, and the crosslinking aid is CaCl 2 and ZnSO 4 in a combination of mass ratio 1:2, and the mass content of the crosslinking aid is 0.25%; (2) Add pectin to the first solution obtained in step (1). The mass ratio of the pectin to the sodium carboxymethylcellulose in step (1) is 8:1. After mixing well, adjust the pH to 7.5 with sodium citrate to obtain a second solution. Keep stirring, with a stirring temperature of 20 °C, a stirring speed of 500 r / min, and a stirring time of 0.5 h to obtain a first crosslinked product; (3) Add pectin to the first crosslinked product obtained in step (2). The mass ratio of the pectin to the sodium carboxymethylcellulose in step (1) is 8:1. Keep stirring, with a stirring temperature of 20 °C, a stirring speed of 500 r / min, and a stirring time of 2 h to obtain a gel; (4) Add water to the gel obtained in step (3) until saturated, wash twice with water, filter with a 10 KDa ultrafiltration membrane to remove the aid, dry at 45 °C for 48 h, and then crush to 20 mesh - 50 mesh to obtain the product.

[0050] Compared with Example 3, in this method, ultrasonic treatment was not carried out during the crosslinking process.

[0051] Comparative Example 3 Different from Example 3, the crosslinking aid is CaCl 2 . The other conditions are the same.

[0052] Comparative Example 4 Different from Example 3, the crosslinking aid is ZnSO 4 . The other conditions are the same.

[0053] Comparative Example 5 Different from Example 3, the crosslinking aid is CaCl 2 and ZnSO 4 in a combination of mass ratio 2:1. The other conditions are the same.

[0054] Comparative Example 6 Different from Example 3, citric acid is used to adjust the pH to 6.0. The other conditions are the same.

[0055] Comparative Example 7 Different from Example 3, sodium citrate is used to adjust the pH to 8.5. The other conditions are the same.

[0056] Result Detection 1. Mechanical Property Detection 1.1 Tap density Detection method: Weigh 40.0 g ± 0.1 g of each product prepared in Examples 1 - 3 and Comparative Examples 1 - 7, record the specific weight value M, put the weighed product into a dry 100 mL glass graduated cylinder, level the powder without compaction, and read the tapped volume V after tapping the graduated cylinder 500 times with a mechanical tap density tester 500 ; after tapping the graduated cylinder 750 times, read the tapped volume V 750 . If the difference between the two volumes is less than 2%, then V 750 is the final tapped volume V f , otherwise repeat with an increment of 1250 taps as needed until the difference between subsequent measured values is less than 2% to obtain the final V f .

[0057] Calculate the tap density DT through the following formula: DT (g / mL) = M / V f .

[0058] Each sample is determined in parallel three times and the average value is taken.

[0059] 1.2 Elastic modulus Detection method: Add 40.0 g ± 0.1 g of the medium solution (artificial gastric juice: water is 1:8, and the artificial gastric juice is prepared according to the method of the Chinese Pharmacopoeia) to a dry beaker and stir at room temperature. Weigh 0.250 g ± 0.005 g of each product prepared in Examples 1 - 3 and Comparative Examples 1 - 7, add them to the beaker, and stir for 30 min. Drain to obtain the material, and use a rheometer to perform a scanning frequency test on the material and measure the value at an angular frequency of 10 rad / s. Each sample is determined in parallel three times and the average value is taken.

[0060] The detection results are shown in Table 1.

[0061] Table 1

[0062] The results show that Examples 1 - 3 of the present invention and Comparative Example 2 have higher tap density and elastic modulus compared with other groups, proving that the present invention improves the mechanical properties of the gel and overcomes the deficiencies of the physically crosslinked gel products through two - step crosslinking and the selection of crosslinking aids.

[0063] 2. Water absorption effect detection Detection method: Accurately weigh 1.0 g of the products prepared in Examples 1 - 3 and Comparative Examples 1 - 7 respectively, place them in a medium of 200 mL of artificial gastric juice: water at a ratio of 1:8 (artificial gastric juice is prepared according to the method of the Chinese Pharmacopoeia), take them out after keeping them in an incubator at 37 °C for 30 minutes, filter off the water with a stainless steel sieve and then weigh them. The weight of the hydrogel after water absorption is m. 2 。 Water absorption multiple = (m 2 - 1) / 1.

[0064] Each sample was measured in parallel three times, and the average value was taken.

[0065] The detection results are shown in Table 2.

[0066] Table 2

[0067] The results show that Examples 1 - 3 of the present invention have higher water absorption capacity. The results of Comparative Example 1 show that two-step crosslinking is an important step of the present invention. By completing crosslinking in two steps, the structure of the hydrogel can be improved and the water absorption capacity can be enhanced. The results of Comparative Example 2 show that the hydrogel without ultrasonic treatment has poor water absorption capacity because it cannot form a good pore structure. The results of Comparative Examples 3 - 7 show that the crosslinking aid and pH value also have important effects on the water absorption capacity. By using appropriate aids and pH values to optimize the stretching form of molecular chains during physical crosslinking and form a good honeycomb structure, the water absorption capacity of the hydrogel can also be increased.

[0068] 3. Fat loss and weight loss experiment Detection method: SPF-grade Kunming mice, male, weighing 18 g - 22 g, were randomly grouped according to body weight, with 8 mice in each group. The experimental groups were respectively gavaged with the products prepared in Examples 1 - 3 and Comparative Examples 1 - 7 once a day at a fixed time. The dosing dose was 100 mg / kg, and the gavage volume was 15 mL / kg. The model group and the blank group were gavaged with an equal volume of distilled water once a day at the same time. Except for the blank group, the mice in the other groups were fed with the same high-fat diet, and the blank group was maintained on a normal diet. Breeding conditions: humidity 40% - 70%, breeding temperature 22 °C - 26 °C, 12 hours of dark and light environment each, free access to water and food.

[0069] The experimental period was 6 weeks, and the mice were weighed at a fixed time every week. The results of the body weight changes of the mice are as Figure 2 and Figure 3 shown.

[0070] Figure 2 The results showed that compared with the mice in the blank group, the body weight of the mice in the model group showed an obvious and faster growth trend. After calculation, a significant difference appeared after 3 weeks, indicating that the obesity model mice were successfully modeled.Figure 2 It is shown that the hydrogels prepared in Examples 1 - 3 of the present invention can well inhibit the weight gain of mice caused by a high - fat diet. Figure 3 The results show that, compared with Example 3, the hydrogel prepared in the comparative example performs relatively poorly in terms of weight loss effect.

[0071] After 6 weeks, all mice were fasted but allowed water for 12 hours, their weights were recorded, they were anesthetized with ether, decapitated, dissected quickly, the peritesticular fat and perirenal fat were completely separated and weighed (fat weight), and the lipid - to - body ratio was calculated. The intestinal contents were collected for testing the intestinal flora.

[0072] Lipid - to - body ratio = fat weight / body weight × 100%.

[0073] The data of the lipid - to - body ratio were processed using SPSS 21 statistical software, and the experimental data were expressed as mean ± SD (standard deviation). The test results of the lipid - to - body ratio are shown in Table 3.

[0074] Table 3

[0075] Note: In the table, when the model group is compared with the blank group, P < 0.01; when the experimental group is compared with the model group, #P < 0.05, ##P < 0.01.

[0076] The results show that the hydrogels prepared in Examples 1 - 3 of the present invention significantly reduced the lipid - to - body ratio of obese model mice. The hydrogels prepared in the examples of the present invention achieved a significant fat - reducing effect by improving the water - absorption capacity and increasing the satiety.

[0077] The test results of the intestinal flora are shown in Table 4.

[0078] Table 4

[0079] The results in Table 4 show that, compared with the mice in the blank group, the abundance of Bacteroidetes in the model group of mice induced by a high - fat diet was significantly reduced, and the abundance of Firmicutes was significantly increased. Firmicutes and Proteobacteria have been proven to account for a larger proportion in the gut microbiota of obese patients. The test results show that, compared with Comparative Examples 1 - 7, the hydrogels prepared in Examples 1 - 3 significantly reduced the abundance of Firmicutes, increased the abundance of Bacteroidetes, improved the balance of the intestinal flora in mice, and reduced the abundance of related bacterial phyla in obese model mice. Therefore, the hydrogel prepared in the present invention has the function of regulating the intestinal flora and can be used for the improvement and prevention of symptoms related to dysbacteriosis.

Claims

1. A method for preparing a hydrogel for improving satiety, characterized in that: The following steps are involved: (1) mixing a cellulose derivative and water, adding a crosslinking aid, and mixing thoroughly to obtain a first solution; in the first solution, the mass content of the cellulose derivative is 0.5%-3%, the crosslinking aid is a combination of CaCl2 and ZnSO4 in a mass ratio of 1:1-4, and the mass content of the crosslinking aid is 0.1%-1%; (2) adding pectin to the first solution obtained in step (1), mixing thoroughly, and adjusting the pH to 7.5-8.0 to obtain a second solution; (3) physically cross-linking the second solution obtained in step (2) under ultrasonic treatment to obtain a first cross-linked product; (4) adding pectin to the first cross-linked product obtained in step (3), and continuously stirring to obtain a gel; (5) removing water from the gel obtained in step (4) to obtain the hydrogel for improving satiety.

2. The preparation method according to claim 1, characterized in that: In step (1), the cellulose derivative is selected from at least one of sodium carboxymethyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl methyl cellulose.

3. The preparation method according to claim 2, characterized in that: In step (1), the cellulose derivative is sodium carboxymethyl cellulose.

4. The preparation method according to claim 1, characterized in that: In step (1), the molecular weight of the cellulose derivative is 100,000-200,000; in step (2), the degree of esterification of the pectin is 58%-62%.

5. The preparation method according to claim 1, characterized in that: In step (1), the mass content of the cellulose derivative in the first solution is 0.5%-2%.

6. The preparation method according to claim 5, characterized in that: In step (1), the mass content of the cellulose derivative in the first solution is 1%.

7. The preparation method according to claim 1, characterized in that: In step (1), in the first solution, the cross-linking aid is a combination of CaCl2 and ZnSO4 in a mass ratio of 1:

2.

8. The preparation method according to claim 1, characterized in that: In step (1), the mass content of the cross-linking aid in the first solution is 0.25%.

9. The preparation method according to claim 1, characterized in that: In step (2), the mass ratio of the pectin to the cellulose derivative in step (1) is 7-9:0.5-1.5; in step (4), the mass ratio of the pectin to the cellulose derivative in step (1) is 7-9:0.5-2.

10. The preparation method according to claim 9, characterized in that: In step (2), the mass ratio of the pectin to the cellulose derivative in step (1) is 8:1; in step (4), the mass ratio of the pectin to the cellulose derivative in step (1) is 8:

1.

11. The preparation method according to claim 1, characterized in that: In step (2), the pH is adjusted to 7.

5.

12. The preparation method according to claim 1, characterized in that: In step (3), the conditions for the ultrasonic treatment are: ultrasonic power 500W-1200W, and ultrasonic time 5min-40min.

13. The preparation method according to claim 12, characterized in that: The conditions of the ultrasonic treatment are: ultrasonic power 1000W, ultrasonic time 20min.

14. The preparation method according to claim 1, characterized in that: In step (4), the continuous stirring conditions are: stirring temperature 10°C-25°C, stirring speed 100r / min-800r / min, and stirring time 1h-3h.

15. The preparation method according to claim 1, characterized in that: In step (5), the method for removing moisture is evaporative drying, and the conditions for evaporative drying are: drying at 25°C-50°C for 24h-72h.

16. The preparation method according to claim 1, characterized in that: In step (5), before removing the water, the method further includes the steps of: adding water to the gel obtained in step (4) until saturated, washing with water 2 to 3 times, and filtering with an ultrafiltration membrane.

17. The preparation method according to claim 1, characterized in that: The specific steps include: (1) adding sodium carboxymethyl cellulose to water, stirring until fully dissolved, adding a cross-linking aid while stirring, and mixing thoroughly to obtain a first solution; in the first solution, the mass content of sodium carboxymethyl cellulose is 0.5%-3%, the cross-linking aid is a combination of CaCl2 and ZnSO4 in a mass ratio of 1:1-4, and the mass content of the cross-linking aid is 0.1%-1%; (2) adding pectin to the first solution obtained in step (1), wherein the mass ratio of the pectin to the sodium carboxymethyl cellulose in step (1) is 7-9:0.5-1.5, and after fully mixing, adjusting the pH to 7.5-8.0 to obtain a second solution; (3) placing the second solution obtained in step (2) into an ultrasonic instrument and performing physical crosslinking under ultrasonic treatment at an ultrasonic power of 500 W to 1200 W and an ultrasonic time of 5 min to 40 min to obtain a first crosslinked product; (4) taking out the first cross-linked product obtained in step (3), adding pectin, wherein the mass ratio of the pectin to the sodium carboxymethyl cellulose in step (1) is 7-9:0.5-2, and stirring is continued at a stirring temperature of 10°C-25°C, a stirring speed of 100r / min-800r / min, and a stirring time of 1h-3h to obtain a gel; (5) Add water to the gel obtained in step (4) until saturated, wash with water 2-3 times, filter with a 10KDa ultrafiltration membrane to remove the additive, dry at 25°C-50°C for 24h-72h, and then crush to 20-50 mesh to obtain the hydrogel for improving satiety.

18. A hydrogel for improving satiety prepared according to the preparation method according to any one of claims 1 to 17.

19. Use of the satiety-enhancing hydrogel according to claim 18 in the preparation of weight loss products.

20. The use according to claim 19, characterized in that The weight loss product is food, medicine or health product.

21. Use of the satiety-enhancing hydrogel according to claim 18 in preparing a product having the function of regulating intestinal flora.

22. The use according to claim 21, characterized in that The product having the function of regulating intestinal flora is food, medicine or health product.

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