Pet chewable tablets containing pagodatree flower bud modified extract probiotic microcapsules and preparation method of pet chewable tablets

Abstract

The invention discloses pet chewable tablets containing pagodatree flower bud modified extract probiotic microcapsules and a preparation method of the pet chewable tablets, and belongs to the technical field of pet food preparation. The preparation method comprises the following steps: adding a probiotic suspension, Tween 80 and glycerol into a mixed solution of the sophora flower bud modified extract and the whey protein isolate, stirring, and freeze-drying to obtain the probiotic microcapsule; uniformly mixing chicken powder, meat and bone meal, fruit and vegetable powder, milk powder and maltodextrin, adding a mixed solution containing gelatin and carrageenan, uniformly mixing, and drying to obtain a chewable tablet mixture; and uniformly mixing the chewable tablet mixture and the probiotic microcapsules, and tabletting and forming to obtain the probiotic chewable tablet. According to the preparation method, the concentration and embedding efficiency of the probiotics in the microcapsules are remarkably improved, the survival rate of the probiotics in simulated gastric juice and intestinal juice is increased, and the prepared chewable tablets have good texture characteristics and sensory quality, can better retain the activity of the probiotics and have good storage stability of the probiotics.

Description

Technical Field

[0001] The invention relates to the technical field of pet food preparation, and in particular to a pet chewable tablet containing probiotic microcapsules of modified Sophora japonica flower extract and a preparation method thereof. Background Art

[0002] With the increase in the number of pets and the increasing attention of pet owners to their pets' health, functional pet foods related to intestinal health have gradually become the focus of research and development. Intestinal health is closely related to the overall health of pets, and probiotics have been widely used in pet foods because of their significant role in maintaining the balance of intestinal microecology and enhancing host immunity. Pet foods containing probiotics on the market usually exist in the form of dry food, wet food, oral supplements, etc., but most pet foods containing probiotics involve heating and sterilization during the production process, and are easily affected by heat, humidity, oxygen and other factors and lose part or all of their activity. In addition, when probiotics enter the gastrointestinal tract of pets, they face the challenges of harsh environments such as gastric acid and bile, which also greatly reduces their survival rate in the gastrointestinal tract, thereby affecting their expected health conditioning effects. In order to overcome the problem of probiotic survival in the gastrointestinal tract, microencapsulation technology, as an effective encapsulation technology, has gradually attracted attention in the field of pet food. Microcapsule technology wraps probiotics in protective materials, such as natural polysaccharides and polymers, to form a tiny capsule structure, which can effectively protect probiotics from harmful factors such as gastric acid and bile. Microcapsules can ensure that probiotics remain active when passing through the gastrointestinal tract and are released in specific areas of the intestine, thereby maximizing the health benefits of probiotics.

[0003] Traditional drying methods (such as spray drying or hot air drying) often cause thermal damage to probiotics due to high temperatures, significantly reducing the survival rate. Freeze-drying technology effectively avoids the inactivation of heat-sensitive bacteria through a low-temperature (usually below -40°C) dehydration mechanism, retaining their metabolic activity to the greatest extent. At the same time, this technology can reduce the moisture content in the microcapsules to below 5%, significantly inhibiting microbial metabolism and oxidation reactions during storage, thereby improving the long-term stability of the product at room temperature. In addition, the synergistic effect of the low moisture state and the microcapsule wall material (such as polysaccharides or proteins) can enhance the tolerance of probiotics to extreme environments of gastrointestinal fluid (such as low pH gastric acid, high bile salts), ensuring that more active bacteria are targeted and delivered to the intestines for colonization. Therefore, freeze-drying technology has become a key process for the preparation of highly active probiotic microcapsules.

[0004] Sophora japonica contains a large number of flavonoids and polysaccharides such as rutin and quercetin. Sophora japonica or its extracts have multiple functions such as antioxidant, antibacterial and immune regulation. In recent years, our laboratory has found that it also has the effect of prebiotics and can promote the growth of probiotics in various systems. However, Sophora japonica extract has the problems of poor water solubility and weak stability, which limits its application in pet food. How to modify Sophora japonica extract to make it more water-soluble and bioavailable, and co-encapsulate it with probiotic microcapsules to maximize its stability and functionality, while also protecting probiotics from the adverse external environment, improving their survival rate, and synergistically improving pet health.

[0005] There are many pet foods containing probiotics on the market, but there are few products and reports on probiotics encapsulated in microcapsules and added to pet foods. Through microencapsulation technology, pet food can not only provide more efficient probiotic supplements, but also improve the market competitiveness of products while ensuring the health of pets. In addition, the production of pet food involves high temperature, high pressure, wet heat and other processes, which will cause the loss of probiotic activity. Therefore, applying probiotic microcapsules to pet food production as losslessly as possible and maintaining their biological activity has become a bottleneck problem that is urgently waiting to be solved. Summary of the invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a pet chewable tablet containing probiotic microcapsules of modified Sophora japonica extract and a preparation method, so as to solve the problems that the existing pet food preparation process is difficult to combine with probiotics, and the probiotic activity and health value of the prepared food are low.

[0007] The technical solution of the present invention to solve the above technical problems is as follows:

[0008] A method for preparing a pet chewable tablet containing probiotic microcapsules of modified Sophora japonica extract, comprising the following steps:

[0009] (1) adding a probiotic suspension, Tween 80 and glycerol to a mixed solution containing a modified Sophora japonica extract and whey protein isolate, stirring, and finally freeze-drying to prepare probiotic microcapsules;

[0010] (2) firstly, chicken meal, meat and bone meal, fruit and vegetable powder, milk powder and maltodextrin are mixed evenly, then a mixed solution containing gelatin and carrageenan is added, stirred and mixed evenly, and finally dried to obtain a chewable tablet mixture;

[0011] (3) Evenly mixing the chewable tablet mixture obtained in step (2) and the probiotic microcapsules obtained in step (1), and pressing them into tablets to obtain a product.

[0012] Furthermore, the modified extract of Sophora japonica seed in step (1) is prepared by the following method: firstly mixing Sophora japonica seed powder and water, adjusting the pH for the first time, ultrasonic treatment, then adding inulin and stirring evenly to react, and finally adjusting the pH again, collecting the supernatant by centrifugation, and freeze-drying to obtain the extract.

[0013] Furthermore, the mass ratio of the sophora japonica flour to water is (0.5-2): (80-120); and the added amount of inulin is 0.1%-0.3% of the total mass of the sophora japonica flour and water.

[0014] Preferably, the mass ratio of the sophora japonica flour to water is 1:100; and the added amount of inulin is 0.2% of the total mass of the sophora japonica flour and water.

[0015] Further, a 3-5 mol / L NaOH solution is used to adjust the pH to 10-12 for the first time; the temperature of the ultrasonic treatment is 40-60°C, the power is 100-200 W, and the time is 20-40 min; the temperature of the reaction is 40-60°C, and the time is 20-40 min; a 3-5 mol / L HCl solution is used to adjust the pH to 6-8 again; the centrifugal speed is 2000-4000 rpm, and the time is 10-30 min; and the mixture is frozen at -30 to -10°C overnight before freeze-drying, and the freeze-drying time is 30-50 h.

[0016] Preferably, the pH is first adjusted to 11 using a 4 mol / L NaOH solution; the temperature of the ultrasonic treatment is 50°C, the power is 150 W, and the time is 30 min; the temperature of the reaction is 50°C, and the time is 30 min; the pH is again adjusted to 7 using a 4 mol / L HCl solution; the centrifugal speed is 3000 rpm, and the time is 20 min; and the mixture is frozen at -20°C overnight before freeze-drying, and the freeze-drying time is 48 h.

[0017] Furthermore, the concentration of the probiotic suspension in step (1) is 1×10 9 -5×10 9 CFU / mL; the concentration of the modified Sophora japonica extract in the mixed solution is 5-20 mg / mL, and the concentration of the whey protein isolate is 30-50 mg / mL; the volume ratio of the probiotic suspension to the mixed solution is (3-7):(10-30); the added amount of Tween 80 is 1%-3% of the total mass of the mixed solution and the probiotic suspension, and the added amount of glycerol is 1%-3% of the total mass of the mixed solution and the probiotic suspension.

[0018] Preferably, in step (1), the concentration of the modified Sophora japonica seed extract in the mixed solution is 10 mg / mL, the concentration of the whey protein isolate is 40 mg / mL; the volume ratio of the probiotic suspension to the mixed solution is 5:20; the amount of Tween 80 added is 2% of the total mass of the mixed solution and the probiotic suspension, and the amount of glycerol added is 2% of the total mass of the mixed solution and the probiotic suspension.

[0019] Furthermore, the probiotic suspension is prepared by the following method:

[0020] The probiotics activated at least three times were centrifuged at 4000 rpm for 5 min, washed at least three times with sterile saline phosphate buffer (PBS), and then resuspended in PBS to a concentration of 1×10 9 -5×10 9 CFU / mL of probiotic suspension.

[0021] Furthermore, in step (1), the mixture is pre-cooled at -90 to -70°C for 5 to 7 hours before freeze drying, and the freeze drying time is 30 to 40 hours.

[0022] Preferably, in step (1), the mixture is precooled at -80°C for 6 hours before freeze drying, and the freeze drying time is 36 hours.

[0023] Furthermore, in step (2), the mass ratio of chicken meal, meat and bone meal, fruit and vegetable powder, milk powder, maltodextrin and the mixed solution is (40-60): (10-30): (1-10): (10-30): (1-10): (20-40); the mass concentration of gelatin in the mixed solution is 0.5%-2%, and the concentration of carrageenan is 1%-4%.

[0024] Preferably, in step (2), the mass ratio of chicken meal, meat and bone meal, fruit and vegetable powder, milk powder, maltodextrin and the mixed solution is 50:20:5:20:5:33; the mass concentration of gelatin in the mixed solution is 1.1%, and the concentration of carrageenan is 2.2%.

[0025] Furthermore, in step (2), the drying temperature is 40-60° C., the drying time is 20-30 min, and the material is turned over every 5-10 min during the drying period.

[0026] Preferably, the drying temperature in step (2) is 50° C., the drying time is 25 min, and the material is turned over every 10 min during the drying period.

[0027] Furthermore, in step (3), the mass ratio of the chewable tablet mixture to the probiotic microcapsules is (5-20): (0.3-0.7).

[0028] Preferably, in step (3), the mass ratio of the chewable tablet mixture to the probiotic microcapsules is 10:0.5.

[0029] A pet chewable tablet containing probiotic microcapsules of modified Sophora japonica extract is prepared by the preparation method.

[0030] The present invention has the following beneficial effects:

[0031] (1) The present invention uses a modified extract of Sophora japonica and Lactobacillus paracasei to freeze-dry and prepare co-encapsulated microcapsules. The addition of the modified extract of Sophora japonica significantly increases the concentration and encapsulation efficiency of probiotics in the microcapsules, improves the microstructure of the microcapsules before and after simulated digestion, and thus enhances the survival rate of probiotics in simulated gastric juice and intestinal juice. This can not only expand the use of Sophora japonica and its modified extract, but also increase the survival rate of probiotics in adverse environments, thereby promoting their probiotic effects.

[0032] (2) The present invention uniformly mixes certain raw materials, gelatin, carrageenan and water, first dries to a certain degree, and then mixes and compresses the mixture with the modified Sophora japonica extract probiotic microcapsules to form chewable tablets. The chewable tablets have good texture characteristics and sensory quality, can better retain the activity of probiotics, and have good probiotic storage stability; the number of viable bacteria in all embodiments stored at 4°C for 50 days is higher than 6log CFU / g, among which the probiotic retention rate and storage stability of embodiment 2 are the highest, and the number of viable bacteria is still close to 7log CFU / g after 60 days of storage. The present invention is suitable for the preparation of microcapsules of thermosensitive probiotics and their products, and has important application value in the field of pet food and health. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The scanning electron microscope images of the microcapsules in the test example before and after simulated digestion. DETAILED DESCRIPTION

[0034] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0035] Embodiment 1:

[0036] A method for preparing probiotic microcapsules containing modified Sophora japonica seed extract and pet chewable tablets thereof, comprising the following steps:

[0037] (1) Preparation of bacterial suspension

[0038] The probiotics activated three times were centrifuged at 4000 rpm for 5 min, washed three times with sterile saline phosphate buffer (PBS), and then resuspended in PBS to a concentration of 1×10 9 The probiotic suspension of CFU / mL is ready for use.

[0039] (2) Extraction and modification of Sophora japonica extract

[0040] First, the Sophora japonica seeds were crushed and passed through a 40-mesh sieve. The Sophora japonica seeds powder and pure water were mixed evenly at a mass ratio of 1:100. The pH value was then adjusted to 11 with a 4.0 mol / L NaOH solution. Ultrasound was performed at 150 W for 30 min at a temperature of 50°C. Then, 0.2% inulin of the total mass of the Sophora japonica seeds powder and pure water was added. The mixture was stirred and reacted for 30 min, and the temperature was maintained at 50°C. Finally, the pH value was adjusted to 7 with a 4.0 mol / L HCl solution. The mixture was centrifuged at 3000 rpm for 20 min. The supernatant was collected, frozen at -20°C overnight, and vacuum freeze-dried for 48 h to obtain the Sophora japonica seeds modified extract.

[0041] (3) Preparation of wall material solution

[0042] 0.1 g of the prepared modified Sophora japonica extract was dissolved in 20 mL of PBS and stirred at room temperature for 2 min on a magnetic stirrer. Then 0.8 g of whey protein isolate was added to the resulting solution, the rotation speed was adjusted to 1200 rpm, and the mixture was stirred evenly to obtain a wall material solution for use.

[0043] (4) Preparation of microcapsules

[0044] 5 mL of the probiotic suspension obtained in step (1) was added to the wall material solution obtained in step (3), and 2% of the total mass of the probiotic suspension and the wall material solution was added with Tween 80 and 2% of glycerol, and stirred with a magnetic stirrer for 10 minutes. The solution obtained after stirring was divided into culture dishes, wrapped with plastic wrap, and placed in a -80°C refrigerator for precooling for 6 hours; finally, the precooled product was placed in a vacuum freeze dryer, the vacuum degree was maintained at -100 MPa, and vacuum freeze-dried for 36 hours, and the dried microcapsules were collected and stored at 4°C.

[0045] (5) Raw material mixing for chewable tablets

[0046] The main raw materials are accurately weighed according to the following proportions (mass percentage): 50% chicken meal, 20% meat and bone meal, 5% fruit and vegetable powder, 20% milk powder, and 5% maltodextrin. These raw materials are placed in a mixing device and fully mechanically stirred to ensure that the ingredients are evenly distributed.

[0047] At the same time, 0.33% gelatin was pre-soaked in 30% sterile water for 30 minutes to achieve full hydration to form a solution. After that, 0.67% carrageenan was added to the gelatin solution and heated and dissolved in a water bath at 60°C to form a uniform colloidal solution (the above percentages are based on the total mass of the main raw materials). The colloidal solution was slowly and in batches poured into the main raw material mixture after mechanical stirring, and continuous mechanical stirring was performed to ensure that the colloid and the raw materials were fully integrated to form a uniform mixture.

[0048] (6) Drying of chewable tablet raw materials

[0049] The uniform mixture obtained in step (5) was transferred to a constant temperature drying oven, and the drying temperature was set to 50° C. for 25 minutes of drying. During the drying process, the material was turned over every 10 minutes to ensure uniform drying of the material and prevent agglomeration of particles.

[0050] (7) Add probiotic microcapsules

[0051] The dried product of step (6) is taken out of the drying oven, and after cooling to room temperature, 0.5 g of the probiotic microcapsules obtained in step (4) are added to every 10 g, and then mixed thoroughly to ensure that the probiotics are evenly distributed throughout the material, thereby ensuring that the content of probiotics in each chewable tablet is uniform.

[0052] (8) Tablet molding

[0053] The final product obtained in step (7) is fed into a tablet press and tableted according to the standard of 2 g per tablet. The pressure and time must be controlled during the tableting process to ensure that the hardness and shape of each chewable tablet meet the standard, while ensuring the stability of the product and the characteristics of being easy for pets to chew. After the tableting is completed, a quality inspection is carried out to ensure that the quality and composition of each chewable tablet meet the preset standards, and finally packaged and stored.

[0054] Embodiment 2:

[0055] A method for preparing probiotic microcapsules containing modified Sophora japonica seed extract and pet chewable tablets thereof, comprising the following steps:

[0056] The preparation method is the same as that of Example 1, except that the mass of the modified Sophora japonica bud extract in step (3) is changed to 0.2 g, and the other steps remain unchanged.

[0057] Embodiment 3:

[0058] A method for preparing probiotic microcapsules containing modified Sophora japonica seed extract and pet chewable tablets thereof, comprising the following steps:

[0059] The preparation method is the same as that of Example 1, except that the mass of the modified Sophora japonica bud extract in step (3) is changed to 0.4 g, and the other steps remain unchanged.

[0060] Comparative Example 1:

[0061] A method for preparing a probiotic microcapsule without prebiotics and a pet chewable tablet thereof, comprising the following steps:

[0062] (1) Preparation of bacterial suspension

[0063] The probiotics activated three times were centrifuged at 4000 rpm for 5 min, washed three times with sterile saline phosphate buffer (PBS), and then resuspended in PBS to a concentration of 1×10 9 The probiotic suspension of CFU / mL is ready for use.

[0064] (2) Preparation of wall material solution

[0065] 0.8 g of whey protein isolate was added to 20 mL of sterile saline phosphate buffer (PBS), and the rotation speed was adjusted to 1200 rpm and stirred evenly to obtain a wall material solution for use.

[0066] (3) Preparation of microcapsules

[0067] 5 mL of the probiotic suspension obtained in step (1) was added to the wall material solution obtained in step (2), and Tween 80 and 2% glycerol were added in an amount of 2% of the total mass of the probiotic suspension and the wall material solution, and stirred with a magnetic stirrer for 10 min. The solution obtained after stirring was divided into culture dishes, wrapped with plastic wrap, and placed in a -80°C refrigerator for precooling for 6 h; finally, the precooled product was placed in a vacuum freeze dryer, the vacuum degree was maintained at -100 MPa, and vacuum freeze-dried for 36 h, and the dried microcapsules were collected and stored at 4°C.

[0068] (4) Raw material mixing for chewable tablets

[0069] The main raw materials are accurately weighed according to the following proportions (mass percentage): 50% chicken meal, 20% meat and bone meal, 5% fruit and vegetable powder, 20% milk powder, and 5% maltodextrin. These raw materials are placed in a mixing device and fully mechanically stirred to ensure that the ingredients are evenly distributed.

[0070] At the same time, 0.33% gelatin was pre-soaked in 30% sterile water for 30 minutes to achieve full hydration to form a solution. After that, 0.67% carrageenan was added to the gelatin solution and heated and dissolved in a water bath at 60°C to form a uniform colloidal solution (the above percentages are based on the total mass of the main raw materials). The colloidal solution was slowly and in batches poured into the main raw material mixture after mechanical stirring, and continuous mechanical stirring was performed to ensure that the colloid and the raw materials were fully integrated to form a uniform mixture.

[0071] (5) Drying of chewable tablet raw materials

[0072] The uniform mixture obtained in step (4) was transferred to a constant temperature drying oven, and the drying temperature was set to 50° C. for 25 minutes of drying. During the drying process, the material was turned over every 10 minutes to ensure uniform drying of the material and prevent agglomeration of particles.

[0073] (6) Add probiotic microcapsules

[0074] The dried product of step (5) is taken out of the drying oven, and after cooling to room temperature, 0.5 g of the probiotic microcapsules obtained in step (3) are added to every 10 g, and then mixed thoroughly to ensure that the probiotics are evenly distributed in the entire material, thereby ensuring that the content of probiotics in each chewable tablet is uniform.

[0075] (7) Tablet molding

[0076] The final product obtained in step (6) is fed into a tablet press and tableted according to the standard of 2 g per tablet. The pressure and time must be controlled during the tableting process to ensure that the hardness and shape of each chewable tablet meet the standard, while ensuring the stability of the product and the characteristics of being easy for pets to chew. After the tableting is completed, a quality inspection is carried out to ensure that the quality and composition of each chewable tablet meet the preset standards, and finally packaged and stored.

[0077] Comparative Example 2:

[0078] A method for preparing inulin-containing probiotic microcapsules and pet chewable tablets thereof comprises the following steps:

[0079] The preparation method is the same as that of Comparative Example 1, except that the preparation of the wall material solution in step (2) is changed to:

[0080] Add 0.8 g of whey protein isolate and 0.2 g of inulin into 20 mL of sterile saline phosphate buffer (PBS), adjust the speed to 1200 rpm and stir evenly to obtain a wall material solution for use, and the other steps remain unchanged.

[0081] Comparative Example 3:

[0082] A method for preparing probiotic microcapsules containing Sophora japonica extract and pet chewable tablets thereof comprises the following steps:

[0083] The preparation method is the same as that of Example 1, except that the preparation method of the Sophora japonica extract in step (2) is changed to:

[0084] First, the Sophora japonica seeds were crushed and passed through a 40-mesh sieve. The Sophora japonica seeds powder and pure water were evenly mixed in a mass ratio of 1:100, and the mixture was boiled for 30 minutes, and then ultrasonicated at 100W for 30 minutes. The resulting solution was filtered, and finally the filtrate was frozen at -20°C overnight and freeze-dried for 48 hours to obtain the Sophora japonica seeds extract. The Sophora japonica seeds modified extract used in the subsequent steps was replaced with the Sophora japonica seeds extract, and the other steps remained unchanged.

[0085] Test example:

[0086] (1) Determination of the encapsulation efficiency of probiotic microcapsules

[0087] Take 0.1 g of each probiotic microcapsule prepared in Examples 1-3 and Comparative Examples 1-3 and dissolve them in 900 μL of encapsulation solution (0.2 mol / L sodium bicarbonate and 0.06 mol / L trisodium citrate, pH adjusted to 7.8-8.2), stir well until complete encapsulation, and then use PBS for gradient dilution to determine the number of viable bacteria.

[0088] Embedding rate (%) = number of viable bacteria after embedding / number of viable bacteria before embedding × 100%; the embedding rate results are shown in Table 1.

[0089] Table 1 Microcapsule embedding efficiency

[0090]

[0091] From the results in Table 1, it can be seen that the concentration of probiotics in the microcapsules prepared in all embodiments of the present invention is significantly higher than that in Comparative Example 1, and the embedding rates of all embodiments are significantly higher than those in Comparative Example 1 and Comparative Example 2, among which Embodiment 2 and Embodiment 3 have the highest embedding rates, which are significantly higher than Comparative Example 3 and Embodiment 1.

[0092] (2) Survival rate of probiotics in microcapsules after exposure to simulated gastrointestinal fluid

[0093] Preparation of simulated gastric fluid (SGF): Adjust the pH of 9 g / L NaCl solution to 2.0 with HCl solution (0.1 mol / L), add 0.3% (w / v) pepsin (1:3000) to dissolve, filter with a 0.22 μm filter membrane for sterilization, and refrigerate at 4°C for use.

[0094] Preparation of simulated small intestinal fluid (SIF): Use NaOH (0.1 mol / L) to adjust the pH value of PBS solution to 8.0, add 0.1% (w / v) pancreatic enzyme (1:250) and 0.3% (w / v) bile salt (ox bile salt BR) to dissolve, filter with a 0.22 μm filter membrane for sterilization, and refrigerate at 4°C for use.

[0095] Simulating the continuous gastrointestinal fluid digestion process: 0.1 g of each example and comparative example microcapsule was weighed and placed in a glass bottle, 900 μL of simulated gastric fluid was added, and the mixture was incubated and digested on a shaker at 37°C and 100 rpm for 2 h. The simulated gastric fluid was removed with a sterile pipette tip to terminate the SGF digestion reaction. Next, the microcapsules were redispersed in 900 μL SIF, and incubated and digested on a shaker at 37°C and 100 rpm for 2 h. After the digestion, the mixture was centrifuged at 4000 rpm for 5 min, the supernatant was removed to terminate the SIF digestion reaction, and finally the precipitate was redispersed in 9 mL of sterile encapsulation solution, and then gradiently diluted with PBS to count the viable bacteria.

[0096] Survival rate in simulated gastrointestinal fluid (%) = number of viable bacteria after simulation / number of viable bacteria before simulation × 100%. The survival rate results of microcapsules in simulated gastric fluid for 2 hours and simulated continuous gastrointestinal fluid for 4 hours are shown in Table 2.

[0097] Table 2 Survival rate of probiotics in microcapsules after being exposed to simulated gastrointestinal fluid

[0098] Embedding group SGF (stomach) survival rate (%) SIF (intestine) survival rate (%) Comparative Example 1 <![CDATA[80.25±0.53 a ]]> <![CDATA[70.86±0.12 a ]]> Comparative Example 2 <![CDATA[81.98±0.89 ab ]]> <![CDATA[72.98±0.66 b ]]> Comparative Example 3 <![CDATA[82.63±0.75 b ]]> <![CDATA[73.57±0.84 b ]]> Example 1 <![CDATA[83.12±1.16 b ]]> <![CDATA[76.35±0.53 c ]]> Example 2 <![CDATA[86.42±0.21 c ]]> <![CDATA[79.25±0.38 d ]]> Example 3 <![CDATA[84.85±0.21 b ]]> <![CDATA[77.51±0.73 c ]]>

[0099] As shown in Table 2, after 2 hours of simulated gastric fluid, the survival rates of all embodiments and comparative example 3 were significantly higher than those of comparative example 1; after simulating continuous gastrointestinal fluid, the survival rates of comparative examples 2 and 3 were significantly higher than those of comparative example 1, but their survival rates were significantly lower than those of all embodiments, among which the survival rate of embodiment 2 in simulated gastric fluid and intestinal fluid was the highest, significantly higher than that of other embodiments. This indicates that the microcapsules prepared by co-encapsulation of prebiotics and probiotics are beneficial to improving the survival rate of probiotics in simulated gastrointestinal fluid, and the effect of Sophora japonica extract, especially the modified extract, is better.

[0100] (3) Scanning electron microscopy characterization

[0101] Take 0.1g of each microcapsule prepared in Example 1-3 and Comparative Example 1-3, add 900μL of simulated intestinal fluid, incubate and digest for 2h at 37℃ and 100rpm on a shaker, remove the simulated intestinal fluid after digestion, place the digested microcapsules in a -20℃ freezer overnight, and then freeze-dry for 36h, collect the freeze-dried microcapsules and the undigested microcapsules for SEM observation. The SEM results are shown in Figure 1 shown.

[0102] Depend on Figure 1It can be seen that the microcapsules prepared in all examples have a relatively dense structure before simulated digestion, while comparative examples 1 and 2 are relatively loose; after simulated digestion, the surface voids of all treated microcapsules become larger, but the microcapsule structures of comparative example 3 and all examples are still relatively dense, among which the structures of examples 2 and 3 are relatively tight before and after simulated digestion, which indicates that the addition of an appropriate amount of modified Sophora japonica flower extract promotes the microstructure of the microcapsules, thereby increasing the survival rate of the examples (especially example 2) in simulated gastrointestinal fluid.

[0103] (4) Completion rate and probiotic retention rate of pet chewable tablets

[0104] For chewable tablets, weigh the mixed material before tableting, and weigh the formed chewable tablets after tableting. Calculate the completion rate based on the weight:

[0105] Completion rate (%) = weight after tableting / weight before tableting × 100%;

[0106] The retention rate of probiotics in pet chewable tablets = (10.5×probiotic concentration in chewable tablets) / (0.5×probiotic concentration in microcapsule).

[0107] The results of the completeness rate and probiotics retention rate of the pet chewable tablets prepared in Examples 1-3 and Comparative Examples 1-3 are shown in Table 3.

[0108] Table 3 Completion rate and probiotic retention rate of pet chewable tablets

[0109]

[0110] As can be seen from Table 3, the completion rates of all comparative examples and embodiments are above 99%, among which the completion rate of embodiment 2 is the highest. The retention rates of probiotics after preparing chewable tablets are very different, and the retention rates of all comparative examples are low, significantly lower than those of all embodiments, among which comparative example 1 is the lowest, embodiment 2 is the highest, followed by embodiment 3, embodiment 1, comparative example 3 and comparative example 2, further illustrating that the addition of prebiotics, especially the modified extract of Sophora japonica, has a great effect on improving the retention rate of probiotics during processing.

[0111] (5) Texture characteristics of pet chewable tablets

[0112] The SMS texture analyzer was used to determine the texture characteristics of pet chewable tablets. The main operation method is: place the pet chewable tablets on a horizontal operating table, use the P36R probe and texture profile analysis (TPA) test, the pre-test speed is 1mm / s, the test speed is 2mm / s, the post-test speed is 2mm / s, the deformation ratio is set to 50%, and the total cycle test is 2 times. The trigger force is 5g, each sample is measured 3 times, and the average value is finally obtained. The texture characteristics of the pet chewable tablets are shown in Table 4.

[0113] Table 4 Texture characteristics of chewable tablets

[0114]

[0115] As shown in Table 4, compared with Comparative Examples 1-3, all examples have higher elasticity and lower hardness; among them, Example 2 has the best elasticity and adhesiveness, and the lowest hardness and chewiness. Comparative Example 1 has the highest chewiness and hardness, which are significantly higher than other comparative examples and examples.

[0116] (6) Sensory quality

[0117] The chewable tablets were evaluated based on sensory scores, with 10 laboratory members and 10 animal preferences evaluating the tablets. They were evaluated and scored from four aspects: appearance, smell, texture and animal preference. The sensory scoring criteria are shown in Table 5, and the evaluation results are shown in Table 6.

[0118] Table 5 Sensory scoring criteria for chewable tablets

[0119]

[0120] Table 6 Sensory evaluation table of chewable tablets

[0121]

[0122] It can be seen from Table 6 that, compared with Comparative Examples 1-3, all Examples have complete appearance, uniform color, moderate texture, high appearance and texture scores, and high animal preference levels. In particular, Example 2 has the highest animal preference and texture scores, and Example 1 has high appearance and smell scores.

[0123] (5) Study on the storage stability of probiotics in pet chewable tablets

[0124] The prepared pet chewable tablets were stored in a refrigerator at 4°C, and the number of viable bacteria was tested every 10 days. The specific method was to place 2g of chewable tablets in 13mL of PBS and disperse them in a high-speed disperser at 4000rpm for 10min to completely release the probiotics in the microcapsules. Then, after diluting to the appropriate concentration range with sterile saline, 0.1mL was spread on MRS agar medium. The plate was placed in a constant temperature incubator and counted after incubation at 37°C for 48h.

[0125] Table 7 Storage stability of pet chewable tablets (log CFU / g)

[0126]

[0127] Note: Different capital letters indicate that there is significance between a row of data; different lowercase letters indicate that there is significance between a column of data

[0128] As shown in Table 7, with the extension of storage time, the number of viable probiotics in the chewable tablets is constantly decreasing. The number of viable probiotics in Comparative Example 1 is lower than 6log CFU / g after 40 days of storage, and the number of viable probiotics in Comparative Examples 2 and 3 is lower than 6log CFU / g after 50 days of storage. During the entire storage period, the number of probiotics in all embodiments is higher than that in all comparative examples. The number of viable probiotics in all embodiments is higher than 6log CFU / g within 50 days of storage at 4°C, among which the number of viable probiotics in Example 2 is the highest, and the number of viable probiotics is still close to 7log CFU / g after 60 days of storage, indicating that the storage stability of all embodiments is good, and the storage stability of Example 2 is the best. It also shows that the modified extract of Sophora japonica selected in the present invention is better, which is extracted under alkaline conditions and reacts with soluble inulin, thereby enhancing the extraction rate and water solubility of the active ingredients, thereby increasing the probiotic effect.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a pet chewable tablet containing probiotic microcapsules of modified Sophora japonica extract, characterized in that: The following steps are involved: (1) adding a probiotic suspension, Tween 80 and glycerol to a mixed solution containing a modified Sophora japonica extract and whey protein isolate, stirring, and finally freeze-drying to prepare probiotic microcapsules; (2) firstly, chicken meal, meat and bone meal, fruit and vegetable powder, milk powder and maltodextrin are mixed evenly, then a mixed solution containing gelatin and carrageenan is added, stirred and mixed evenly, and finally dried to obtain a chewable tablet mixture; (3) Evenly mixing the chewable tablet mixture obtained in step (2) and the probiotic microcapsules obtained in step (1), and pressing them into tablets to obtain a product.

2. The method for preparing the pet chewable tablets containing probiotic microcapsules of modified Sophora japonica extract according to claim 1, characterized in that: The modified Sophora japonica extract in step (1) is prepared by the following method: firstly mixing Sophora japonica powder and water, adjusting the pH for the first time, ultrasonic treatment, then adding inulin, stirring evenly and reacting, and finally adjusting the pH again, collecting the supernatant by centrifugation, and freeze-drying to obtain the modified Sophora japonica extract.

3. The method for preparing the pet chewable tablets containing probiotic microcapsules of modified Sophora japonica extract according to claim 2, characterized in that: The mass ratio of the sophora japonica flour to water is (0.5-2): (80-120); the added amount of inulin is 0.1%-0.3% of the total mass of the sophora japonica flour and water.

4. The method for preparing the pet chewable tablets containing probiotic microcapsules of modified Sophora japonica extract according to claim 2, characterized in that: The pH value is first adjusted to 10-12 using a 3-5 mol / L NaOH solution; the temperature of the ultrasonic treatment is 40-60°C, the power is 100-200 W, and the time is 20-40 min; the temperature of the reaction is 40-60°C, and the time is 20-40 min; the pH value is again adjusted to 6-8 using a 3-5 mol / L HCl solution; the centrifugal speed is 2000-4000 rpm, and the time is 10-30 min; and the product is frozen overnight at -30 to -10°C before freeze drying, and the freeze drying time is 30-50 h.

5. The method for preparing the pet chewable tablets containing probiotic microcapsules of modified Sophora japonica extract according to claim 1, characterized in that: The concentration of the probiotic suspension in step (1) is 1×10 9 -5×10 9 CFU / mL; the concentration of the modified Sophora japonica extract in the mixed solution is 5-30 mg / mL, and the concentration of the whey protein isolate is 30-50 mg / mL; the volume ratio of the probiotic suspension to the mixed solution is (3-7):(10-20); the added amount of Tween 80 is 1%-3% of the total mass of the mixed solution and the probiotic suspension, and the added amount of glycerol is 1%-3% of the total mass of the mixed solution and the probiotic suspension.

6. The method for preparing the pet chewable tablets containing probiotic microcapsules of modified Sophora japonica extract according to claim 1, characterized in that: In the step (1), the mixture is pre-cooled at -90 to -70°C for 5 to 7 hours before freeze drying, and the freeze drying time is 30 to 40 hours.

7. The method for preparing the pet chewable tablets containing probiotic microcapsules of modified Sophora japonica extract according to claim 1, characterized in that: In the step (2), the mass ratio of chicken meal, meat and bone meal, fruit and vegetable powder, milk powder, maltodextrin and the mixed solution is (40-60): (10-30): (1-10): (10-30): (1-10): (20-40); the mass concentration of gelatin in the mixed solution is 0.5%-2%, and the concentration of carrageenan is 1%-4%.

8. The method for preparing the pet chewable tablets containing probiotic microcapsules of modified Sophora japonica extract according to claim 1, characterized in that: The drying temperature in step (2) is 40-60° C., the drying time is 20-30 min, and the material is turned over every 5-10 min during the drying period.

9. The method for preparing pet chewable tablets containing probiotic microcapsules of modified Sophora japonica extract according to claim 1, characterized in that: The mass ratio of the chewable tablet mixture to the probiotic microcapsules in the step (3) is (5-20): (0.3-0.7).

10. A pet chewable tablet containing probiotic microcapsules of modified Sophora japonica extract, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

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