Slow-release acidity regulator and application thereof in preparation of products for improving intestinal functions of dogs and cats

Abstract

The invention provides a slow-release acidity regulator and application thereof in preparation of products for improving intestinal functions of dogs and cats, the slow-release acidity regulator is formed by microencapsulation of a composite acidity regulating system by a nano-embedding technology, and the composite acidity regulator is intelligently controlled to release according to changes of pH in stomachs of dogs and cats. The sustained-release acidity regulator can dynamically maintain the pH value in the stomach of dogs and cats to be less than or equal to 5.0, the release rate within 6 hours is 57.5%, and the sustained-release acidity regulator has a good sustained-release effect. According to the invention, pH intelligent dynamic regulation and control of the acidifying agent in the stomachs of dogs and cats are realized, the digestibility of nutrient substances is improved, the gastrointestinal tract problem caused by insufficient gastric acid is improved, the technical problem that the traditional acidifying agent is released too early in the stomachs is solved, and the adopted embedding wall material is more in line with the green development trend of pet food; the method has important industrial application value.

Description

Technical Field

[0001] The invention belongs to the field of functional pet food, and particularly relates to a slow-release acidity regulator and application thereof in preparing a product for improving intestinal function of dogs and cats. Background Art

[0002] Pepsinogen is activated into pepsin by gastric acid in a low pH environment. As the pH value increases, the activity of pepsin decreases. The pH in the stomach of dogs and cats is often higher than the ideal threshold, which leads to decreased enzyme activity or even inactivation, affecting protein digestion. Undigested fatty acids will stimulate the intestinal mucosa to secrete mucus, increasing the digestive burden. Undecomposed large molecular proteins enter the lymphatic system through areas with increased intestinal permeability, activate T cells and cause chronic enteritis.

[0003] Regarding the problem of insufficient gastric acid secretion in dogs and cats, the existing technology has the following defects: 1. The release of conventional acidifiers is uncontrollable: Direct acid supplementation can cause a sudden drop in gastric pH, damage the mucosa, and feedback inhibit gastrin secretion. Ordinary acidifiers (such as citric acid and lactic acid) are released rapidly in the stomach. Although they can temporarily lower the gastric pH, they cannot continuously maintain the optimal range (pH ≤ 5.0), resulting in unstable protein digestion efficiency.

[0004] 2. Mismatched pH response range: Conventional pH-sensitive materials (such as sodium alginate) have a fixed response threshold and cannot accurately match the dynamic changes in pH in the stomach of dogs and cats, resulting in premature or delayed release of the acidifier.

[0005] 3. Insufficient stability in gastric acid environment: Some encapsulated materials (such as gelatin and starch) are easily swollen or degraded in gastric acid, causing a sudden release of acidifiers, while overly acid-resistant materials may not be released at all in the stomach and cannot function.

[0006] Therefore, a sustained-release acidifier is developed that dynamically maintains the pH in the stomach of dogs and cats, and achieves continuous and stable release of the acidifier in the stomach. The present invention has very broad application prospects in the intestinal health of dogs and cats. Summary of the Invention

[0007] Technical problems to be solved: In view of the above technical problems, the first object of the present invention is to provide a slow-release acidity regulator.

[0008] The second object of the present invention is to provide a method for preparing a slow-release acidity regulator.

[0009] The third object of the present invention is to provide the use of the sustained-release acidity regulator in the preparation of a product for improving intestinal function in dogs and cats.

[0010] Technical solution: A sustained-release acidity regulator is prepared by microencapsulating a composite acidity regulating system using nano-embedding technology to achieve controlled release; the composite acidity regulator comprises lactic acid, citric acid and fumaric acid.

[0011] The preparation method of the above-mentioned slow-release acidity regulator comprises the following steps: S1 chitin and laccase were added to acetate buffer for reaction, the enzyme was inactivated at high temperature and the precipitate was collected by centrifugation, washed and then added with NaClO2 and NaH2PO4 for secondary reaction, desalted by dialysis and dried to obtain carboxylated chitin; S2. Carboxylated chitin was dissolved in deionized water, homogenized under high pressure, and dried to obtain carboxylated chitin nanofibers. S3. The whey protein was dissolved in 50mmol / L phosphate buffer, maleic anhydride was added and the reaction was stirred. After the reaction was completed, unreacted maleic anhydride was removed by dialysis, and then cysteamine hydrochloride was added. After UV irradiation, cold ethanol was added, the precipitate was collected by centrifugation, and dried to obtain modified whey protein. S4 lactic acid, citric acid and fumaric acid were mixed and ground to obtain a composite acidity regulator; S5. Carboxylated chitin nanofibers, a composite acidity regulator, and carob powder are added to water and stirred evenly. The mixture is ultrasonically treated and then centrifuged to remove free acid. Modified whey protein is then added and mixed evenly. The mixture is frozen and thawed three times. Genipin is then added to form a cross-linked gel. Cold ethanol is then injected, and the mixture is ultrasonically disrupted in an ice bath. Nanoparticles are then collected by centrifugation to produce a sustained-release acidity regulator.

[0012] Preferably, the ratio of chitin to laccase in step S1 is 1-1.5 g:15-25 U.

[0013] Preferably, the reaction temperature in step S1 is 40-45° C., the reaction speed is 150-200 rpm, and the reaction time is 10-16 h.

[0014] Preferably, the temperature for high-temperature enzyme inactivation in step S1 is 70-90° C., and the time for high-temperature enzyme inactivation is 5-15 minutes.

[0015] Preferably, the centrifugal speed in step S1 is 7000-9000 rpm, and the centrifugal time is 10-20 min.

[0016] Preferably, the temperature of the secondary reaction in step S1 is 55-65° C., and the time of the secondary reaction is 3-5 hours.

[0017] Preferably, in step S2, the mass volume ratio of carboxylated chitin to deionized water is 1:50-200.

[0018] Preferably, the pressure of the high-pressure homogenization in step S2 is 150-200 MPa.

[0019] Preferably, in step S3, the mass ratio of whey protein, maleic anhydride and cysteamine hydrochloride is 1:0.03-0.07:0.1-0.4.

[0020] Preferably, the reaction temperature in step S3 is 25° C., the reaction speed is 300-500 rpm, and the reaction time is 1-4 h.

[0021] Preferably, the wavelength of the ultraviolet light in step S3 is 350-370 nm.

[0022] Preferably, the centrifugal speed in step S3 is 5000-6000 rpm, and the centrifugal time is 3-8 min.

[0023] Preferably, in terms of weight percentage, the content of lactic acid in the composite acidity regulator in step S4 is 30-36%, the content of citric acid is 50-60%, and the content of fumaric acid is 10-14%.

[0024] Preferably, in step S5, the mass ratio of the composite acidity regulator, carboxylated chitin nanofibers, modified whey protein and carob powder is 1:22-30:4-8:5-15.

[0025] Preferably, the stirring speed in step S5 is 300-500 rpm, and the stirring time is 1-2.5 h.

[0026] Preferably, the frequency of the ultrasonic treatment in step S5 is 30-50 kHz, the power of the ultrasonic treatment is 100-120 W, and the time of the ultrasonic treatment is 10-20 min.

[0027] Preferably, the freezing temperature in step S5 is -20 to -30°C, and the freezing time is 1 to 3 hours.

[0028] Preferably, the thawing temperature in step S5 is 20-25° C., and the thawing time is 60-120 min.

[0029] Preferably, the amount of genipin added in step S5 is 0.3-0.8 wt%.

[0030] Preferably, the cross-linking temperature in step S5 is 35-45° C., and the cross-linking time is 2-5 hours.

[0031] Preferably, the volume ratio of gel to cold ethanol in step S5 is 1:4-10.

[0032] Preferably, the power of ultrasonic crushing in step S5 is 150-250 W, and the time of ultrasonic crushing is 5-20 min.

[0033] Preferably, the centrifugal speed in step S5 is 8000-10000 rpm, and the centrifugal time is 10-20 min.

[0034] Application of the above-mentioned sustained-release acidity regulator in the preparation of products for improving intestinal function of dogs and cats.

[0035] The mass ratio of the sustained-release acidity regulator in the above-mentioned product for improving intestinal function of dogs and cats as an additive to the staple food of dogs and cats is 0.15~0.3g:100g.

[0036] Beneficial effects: 1. The sustained-release acidity regulator provided by this invention achieves intelligent controlled release through precise regulation of pH-dependent conformational changes. Under acidic conditions (pH <5), the carboxyl groups of the carboxylated chitin nanofibers protonate, reducing their surface charge and strengthening interfiber hydrogen bonds, leading to fiber contraction. Simultaneously, the modified whey protein maintains a compact globular conformation. The two synergistically form a dense network that blocks the release of the composite acidity regulator, resulting in a release rate of less than 5%. When the ambient pH rises (pH >5), the carboxylated chitin nanofibers deprotonate, generating electrostatic repulsion that causes the fibers to swell. Simultaneously, the protein undergoes conformational unfolding, exposing its hydrophobic core and significantly increasing the network porosity. The expanded carboxylated chitin nanofiber network synergizes with the unfolded protein to form macroporous channels, accelerating the release of the composite acidity regulator, thereby lowering the pH.

[0037] 2. The sustained-release acidity regulator provided by the present invention adopts pH-responsive release technology, intelligently releasing the composite acidity regulator when the pH in the stomach increases, dynamically maintaining an intragastric pH environment of ≤5.0. On the one hand, it ensures the continuous and efficient activation of pepsin and improves the efficiency of protein digestion. On the other hand, the sustained-release mechanism avoids mechanical damage to the gastric mucosa caused by sudden pH changes. The release rate within 6 hours is 57.5%, thus overcoming the limitations of traditional acidifiers such as large pH fluctuations and strong mucosal irritation caused by instantaneous action. The content of lactic acid, which exerts an acidifying effect, is 30-36%, the content of citric acid is 50-60%, and the content of fumaric acid is 10-14%. As natural organic acids, they have unique mechanisms of action and synergistic advantages in promoting pet gastrointestinal health. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The release rates of Examples 1 to 4 and Comparative Examples 1 to 4 in simulated artificial gastric fluid. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with examples, which are provided to explain the present invention and are not limited to the following examples: Example 1 This embodiment is the preparation of a slow-release acidity regulator, comprising the following steps: S1. Add 40 g of chitin to 400 mL of acetate buffer (pH 5.0) and mix thoroughly. Add 640 U of laccase and incubate at 42°C and 150 rpm for 12 h. After the reaction, inactivate the enzyme at 80°C for 10 min. Centrifuge at 8000 rpm for 15 min to collect the precipitate, rinse three times, add 8.8 g of NaClO₂ and 220 mL of NaH₂PO₄ (0.1 mol / L), and incubate at 60°C for 4 h. Desalt the precipitate by dialysis (MWCO 10 kDa) and dry it to obtain carboxylated chitin. S2 carboxylated chitin was dissolved in 5160mL of deionized water, homogenized at 150MPa, cycled three times, and dried to obtain carboxylated chitin nanofibers; S3. Dissolve 21 g of whey protein in 450 mL of 50 mmol / L phosphate buffer, add 0.84 g of maleic anhydride, and stir at 25°C and 300 rpm for 2 h. After the reaction, dialyze (MWCO 10 kDa) to remove unreacted maleic anhydride. Then, add 6.3 g of cysteamine hydrochloride. After irradiation with 365 nm ultraviolet light, add cold ethanol, and centrifuge at 5000 rpm for 6 min to collect the precipitate. Dry the precipitate to obtain the modified whey protein. S4 1.02g of lactic acid, 1.62g of citric acid and 0.36g of fumaric acid were mixed and ground to obtain a composite acidity regulator; S5. Add 23 g of carboxylated chitin nanofibers, 1 g of a composite acidity regulator, and 12 g of carob powder to 150 mL of water, stir at 350 rpm for 2 h, and ultrasonically treat at 40 kHz and 100 W for 15 min. Then, centrifuge to remove free acid. Then, add 6 g of modified whey protein and mix well. After freezing at -20°C for 2 h and thawing at 25°C for 90 min, repeat this cycle three times. Then, add 0.75 g of genipin, cross-link at 35°C for 3 h to form a gel, inject 1080 mL of cold ethanol, and ultrasonically disrupt the mixture at 200 W in an ice bath for 12 min. Then, centrifuge at 8000 rpm for 13 min to collect the nanoparticles, which is the sustained-release acidity regulator.

[0040] Example 2 The difference between this example and Example 1 is that the amount of chitin added in this example is 45 g, and the amount of laccase added is 761.5 U.

[0041] Example 3 The difference between this embodiment and embodiment 1 is that the amount of maleic anhydride added in this embodiment is 1.47 g, and the amount of cysteamine hydrochloride added is 2.1 g.

[0042] Example 4 The difference between this embodiment and embodiment 1 is that in this embodiment, the added amount of carboxylated chitin nanofibers is 28 g, and the added amount of modified whey protein is 4 g.

[0043] Comparative Example 1 The difference between this example and Example 1 is that in this comparative example, the carboxylated chitin nanofibers are replaced with sodium alginate.

[0044] Comparative Example 2 The difference between this example and Example 1 is that in this comparative example, the slow-release acidity regulator is replaced by citric acid.

[0045] Comparative Example 3 The difference between this example and Example 1 is that no carboxylated chitin nanofibers are added in this comparative example.

[0046] Comparative Example 4 The difference between this example and Example 1 is that no modified whey protein is added in this comparative example.

[0047] Comparative Example 5 The difference between this example and Example 1 is that no slow-release acidity regulator is added in this comparative example.

[0048] The performance of the slow-release acidity regulators prepared in Examples 1 to 4 and Comparative Examples 1 to 5 was tested, and the results were as follows: Table 1 Cumulative release rates of Examples 1-4 and Comparative Examples 1-5 at different pH values

[0049] As shown in Table 1, the sustained-release acidity regulators prepared in Examples 1-4 exhibited excellent pH-responsive release characteristics: in a simulated artificial gastric fluid environment (initial pH 2.5), the sustained-release acidity regulator remained stable for 1 hour and released at a rate of less than 5% over 2 hours. Adjusting the pH to 5.0 triggered the release mechanism, with a release rate of 33.3-38.4% within 4 hours. After adjusting the pH back to 2.5 again, the release behavior rapidly ceased and remained at the current level. Upon a second adjustment to 5.0, the sustained-release acidity regulator resumed its release function. Comparative Examples 1-4, on the other hand, exhibited completely different release characteristics: under varying acidic conditions, their release behavior exhibited a continuous linear growth trend, with release rates reaching 79.4-93.7% within 6 hours. This non-selective release pattern results in the premature release of a large amount of the active ingredient in the highly acidic environment of the stomach, which not only reduces the utilization of the active ingredient but also potentially triggers adverse reactions such as gastric mucosal irritation.

[0050] like Figure 1As shown, the sustained-release acidity regulators prepared in Examples 1-4 of the present invention exhibited good sustained-release properties, with cumulative release rates ranging from 11.5% to 15.4% within 1 hour and 38.1% to 57.5% within 6 hours, demonstrating an ideal sustained-release effect. In contrast, the release behavior of Comparative Examples 1-4 was significantly too rapid, with release rates reaching 39.4% to 86.5% within 3 hours, failing to achieve effective sustained-release control.

[0051] Table 2 Effects of Examples 1-4 and Comparative Examples 1-5 on Dog Feeding Characteristics

[0052] Table 3 Effects of Examples 1-4 and Comparative Examples 1-5 on Cats' Feeding Characteristics

[0053] As shown in Table 2 and Table 3, compared with Comparative Examples 1 to 5, the sustained-release acidity regulators prepared in Examples 1 to 4, after being blended with the staple food, effectively promoted the digestion and absorption of nutrients by optimizing the pH environment in the stomach, and the weight of dogs and cats increased to varying degrees.

[0054] Table 4 Effects of Examples 1-4 and Comparative Examples 1-5 on Dog and Cat Feces

[0055] As shown in Table 4, compared with Comparative Examples 1 to 5, the sustained-release acidity regulators prepared in Examples 1 to 4 of the present invention improved the fecal quality of dogs and cats. Whey protein and chitin contain natural antimicrobial peptides, which synergistically regulate the intestinal function of dogs and cats with lactic acid, citric acid, and fumaric acid, effectively inhibit the proliferation of protein spoilage bacteria in the intestines of dogs and cats, promote the growth of beneficial bacteria, improve the intestinal microecological balance, and reduce the content of ammonia nitrogen in feces.

[0056] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any person skilled in the art can, without departing from the spirit and technical solution of the present invention, use the methods and technical contents disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A slow-release acidity regulator, characterized in that: The slow-release acidity regulator is prepared by microencapsulating a composite acidity regulating system using nano-encapsulation technology; the composite acidity regulator comprises lactic acid, citric acid and fumaric acid.

2. The method for preparing a slow-release acidity regulator according to claim 1, wherein: The following steps are involved: S1 chitin and laccase were added to acetate buffer for reaction, the enzyme was inactivated at high temperature and the precipitate was collected by centrifugation, washed and then added with NaClO2 and NaH2PO4 for secondary reaction, desalted by dialysis and dried to obtain carboxylated chitin; S2. Carboxylated chitin was dissolved in deionized water, homogenized under high pressure, and dried to obtain carboxylated chitin nanofibers. S3. The whey protein was dissolved in 50 mmol / L phosphate buffer, maleic anhydride was added and stirred, and after the reaction, unreacted maleic anhydride was removed by dialysis, and then cysteamine hydrochloride was added. After ultraviolet light irradiation, cold ethanol was added, the precipitate was collected by centrifugation, and dried to obtain modified whey protein; S4 lactic acid, citric acid and fumaric acid were mixed and ground to obtain a composite acidity regulator; S5. Carboxylated chitin nanofibers, a composite acidity regulator, and carob powder are added to water and stirred evenly. The mixture is ultrasonically treated and then centrifuged to remove free acid. Modified whey protein is then added and mixed evenly. The mixture is frozen and thawed three times. Genipin is then added to form a cross-linked gel. Cold ethanol is then injected, and the mixture is ultrasonically disrupted in an ice bath. Nanoparticles are then collected by centrifugation to produce a sustained-release acidity regulator.

3. The preparation method according to claim 2, wherein: In step S1, the ratio of chitin to laccase is 1-1.5 g:15-25 U.

4. The preparation method according to claim 2, wherein: In step S3, the mass ratio of whey protein, maleic anhydride and cysteamine hydrochloride is 1:0.03-0.07:0.1-0.

4.

5. The preparation method according to claim 2, wherein: In terms of weight percentage, the content of lactic acid in the composite acidity regulator in step S4 is 30-36%, the content of citric acid is 50-60%, and the content of fumaric acid is 10-14%.

6. The preparation method according to claim 2, wherein: In step S5, the mass ratio of the composite acidity regulator, the carboxylated chitin nanofibers, and the modified whey protein carob pod powder is 1:22-30:4-8:5-15.

7. Use of the sustained-release acidity regulator according to claim 1 in preparing a product for improving intestinal function in dogs and cats.

8. The use according to claim 7, characterized in that: The mass ratio of the sustained-release acidity regulator to the staple food of dogs and cats in the product for improving intestinal function of dogs and cats is 0.15-0.3 g:100 g.

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