Resistant starch extracted from green bananas and its use in pet food

Abstract

The application relates to the technical field of food processing and pet nutrition, and particularly relates to resistant starch extracted from green bananas and application of the resistant starch in pet food, wherein the resistant starch is obtained by the following extraction method: (1) preparing pretreated green banana slices; (2) preparing green banana slurry; (3) adding alpha-amylase into the green banana slurry, and performing constant-temperature enzymolysis; then adding composite enzymes to continue the constant-temperature enzymolysis; after the end, high-temperature enzyme inactivation is performed to obtain coarse starch precipitate; (4) preparing starch suspension, first swelling at room temperature, then cold storage and retrogradation; vacuum drying is performed to obtain the resistant starch (CZ01). The resistant starch prepared by the application is excellent in yield, water holding capacity and expansion degree, the in-vitro digestion rate and GI value are obviously decreased, the rapid absorption of carbohydrates can be delayed, the blood glucose level of pets is stabilized, after the pet food added with the resistant starch is fed, the qualified rate of the shape of pet feces is increased, and there are no intestinal discomfort phenomena such as soft stool, diarrhea and flatulence.

Description

Technical Field

[0001] This application relates to the fields of food processing and pet nutrition technology, and more specifically, it relates to a resistant starch extracted from green bananas and its application in pet food. Background Technology

[0002] With the upgrading of pet-raising concepts, fresh pet food is gradually gaining popularity in the market due to its natural nutrition and palatability. However, existing fresh food formulas generally have problems such as a high glycemic index and insufficient ability to regulate intestinal flora. Long-term feeding can easily lead to obesity, blood sugar fluctuations, and intestinal dysfunction in dogs and cats. Resistant starch, as a type of carbohydrate that is difficult to be broken down by digestive enzymes in the small intestine but can be directly fermented and utilized by intestinal flora in the large intestine, has the characteristics of slow glycemic index and prebiotics, and it shows broad application prospects in the field of pet nutrition.

[0003] Unripe bananas are rich in natural RS2-type resistant starch, with a content far exceeding that of ripe bananas. Furthermore, the raw material is widely available and inexpensive, making it a high-quality raw material for preparing resistant starch. Currently, existing technologies primarily focus on the application of resistant starch in human food, lacking customized extraction processes and application solutions for pet food. Simultaneously, existing pet foods often use cereal starch as a carbohydrate source, resulting in a rapid glycemic index, which fails to meet the needs of blood sugar-controlled and gut-friendly pet foods. In addition, conventional resistant starch extraction processes suffer from low purity, poor activity retention, and unstable yields, limiting its large-scale application in pet food. Therefore, there is an urgent need to develop a process for efficiently extracting highly active resistant starch from unripe bananas and applying it to pet food formulations to address the shortcomings of existing pet foods, such as rapid glycemic index and weak intestinal regulation, thus providing new raw material options and technological support for functional pet foods. Summary of the Invention

[0004] To address the technical problems mentioned in the background section, this application provides a resistant starch (CZ01) extracted from green bananas and its application in pet food.

[0005] This application provides a resistant starch (CZ01) extracted from green bananas, using the following technical solution:

[0006] A resistant starch (CZ01) extracted from green bananas is obtained by the following extraction method:

[0007] (1) Select green bananas that are free from mold and insects, peel them and slice them. Use a compound color-protecting inhibitor solution for constant temperature color protection treatment. After treatment, rinse with deionized water and drain the surface moisture to obtain pre-treated green banana slices:

[0008] (2) Mix the pretreated green banana slices with deionized water, add antioxidants, and pulp under low temperature conditions to obtain green banana pulp;

[0009] (3) Add α-amylase to the green banana pulp and hydrolyze at a constant temperature for 30-40 min; then adjust the pH of the system to 4.0-5.0, add the compound enzyme and continue to hydrolyze at a constant temperature for 20-30 min; after the hydrolysis is completed, inactivate the enzyme at high temperature, cool, filter and centrifuge in sequence, discard the supernatant, collect the lower precipitate, wash the precipitate with deionized water to obtain crude starch precipitate;

[0010] (4) Mix the crude starch precipitate and the modified liquid, stir evenly to obtain a starch suspension, and adjust the pH of the system to 4.5-5.5; let it stand at room temperature for 1-2 hours to swell, and then refrigerate at 4-8℃ for 4-6 hours; after refrigeration, vacuum dry until the moisture content is ≤10%, pulverize and sieve to obtain resistant starch (CZ01).

[0011] Preferably, the composite color-protecting inhibitor solution in step (1) is composed of bamboo leaf flavonoids, sodium D-isoascorbate and deionized water in a mass ratio of 2-3:1-1.2:200-300.

[0012] Preferably, in step (3), the mass ratio of green banana pulp, α-amylase and complex enzyme is 1000:2-5:1.5-3.

[0013] Preferably, in step (3), the complex enzyme is composed of saccharifying enzyme and amylopectin in a mass ratio of 5-8:3-4.

[0014] Preferably, the α-amylase in step (3) is a thermostable α-amylase with an enzyme activity ≥2000U / g.

[0015] Preferably, in step (3), the isothermal enzymatic hydrolysis temperature is 55-65℃ and the pH value is 6.0-7.0; the high-temperature enzyme inactivation temperature is 95-100℃ and the high-temperature enzyme inactivation time is 10-15min.

[0016] Preferably, the mass ratio of crude starch precipitate to modified liquid in step (4) is 1-2:4-6.

[0017] Preferably, the modified liquid in step (4) is composed of lactic acid, brown algae oligosaccharide and deionized water in a mass ratio of 1-3:2-5:100.

[0018] An application of the resistant starch (CZ01) extracted from green bananas as described above in the preparation of sugar-controlled and gut-protecting pet food.

[0019] The application of a resistant starch (CZ01) extracted from green bananas in the preparation of sugar-controlled and gut-protecting pet food, wherein the raw material components of the pet food, by mass percentage, include: 30-52% chicken breast, 8-10% chicken heart, 5-10% chicken liver, 8-10% egg, 5-10% carrot, 5-7% spinach, 3-5% kale, 1-3% fish oil, 1.5-3.5% parsley, 3-5% apple, 3-8% resistant starch (CZ01), and 0.5-1.5% chicory root powder.

[0020] A method for preparing pet food includes the following steps:

[0021] Remove tendons, fat, and impurities from chicken breast, chicken heart, and chicken liver; rinse thoroughly with water and cut into 3-6mm cubes. Peel and core carrots and apples, and cut into 4-8mm pieces. Remove yellow leaves, tough roots, and impurities from spinach, kale, and parsley, and rinse thoroughly with water. Place all the above ingredients in a temperature-controlled grinder, maintaining a grindering temperature of 20-30℃, and grind to 80-100 mesh. Set aside. Crack the eggs and beat thoroughly until the egg mixture is smooth and even in texture. Set aside. Prepare the chicken breast, chicken heart, chicken liver, and carrot cubes... Radishes, apples, and eggs are stirred at 200-400 rpm at room temperature for 10-30 minutes until homogeneous. Resistant starch (CZ01), chicory root powder, and fish oil are added, and the mixture is stirred at 200-400 rpm until homogeneous. The homogenization pressure is controlled at 20-30 MPa and the homogenization time is 3-5 minutes. After homogenization, the mixture is dried at 50-55℃ until the moisture content is ≤10%. After drying, it is cooled to room temperature, sterilized, and sealed in packaging to obtain pet food.

[0022] In summary, this application has the following beneficial effects:

[0023] This application uses a compound color-protecting inhibitor made by combining bamboo leaf flavonoids and sodium D-isoascorbate. Compared with a single color-protecting component, the two substances can produce synergistic antioxidant and anti-browning effects, effectively inhibiting the polyphenol oxidation reaction during the processing of green bananas, protecting the starch molecular structure from oxidative damage, avoiding the defects of poor protective effect and low starch purity of a single color-protecting agent, ensuring the original physicochemical properties of starch, and further improving the quality of finished starch.

[0024] This application employs a stepwise enzymatic hydrolysis method, adding α-amylase first and then a complex enzyme, which differs from the simple process of simultaneous enzyme addition. This allows the amylase to act on the starch in stages. First, α-amylase cleaves the long starch chains, and then a complex system of saccharifying enzymes and amylopectin degrades non-resistant starch, precisely modifying the molecular structure of the starch and significantly increasing the yield of resistant starch. This application also incorporates a low-temperature retrogradation process after modification. Compared to processes without low-temperature retrogradation, this allows the starch molecular chains to reassociate and arrange themselves in a regular pattern, forming a dense and stable crystalline structure. This effectively improves the water-holding capacity and swelling degree of resistant starch, reduces in vitro digestibility and GI value, and endows the starch with excellent anti-digestion and low glycemic properties. Furthermore, this application uses a modified solution composed of lactic acid, fucoidan, and deionized water to further optimize the starch surface structure and enhance starch stability. Adding the prepared resistant starch to pet food makes its nutritional structure more balanced. Furthermore, the resistant starch can promote the growth of beneficial intestinal bacteria, improve stool consistency, and reduce intestinal discomfort such as bloating and soft stools. The extraction process described in this application is mild, simple, and controllable, making it easy to scale up production. The reasonable combination of livestock and poultry meat, fruits, and vegetables ensures the prepared pet food is palatable, gentle on the digestive system, and has a balanced sugar content, making it suitable for long-term consumption by various pets. Therefore, it possesses high production application value and promising prospects for promotion. Detailed Implementation

[0025] The present application will be further described in detail below with reference to the embodiments.

[0026] Bamboo leaf flavonoids used in the examples and comparative examples of this application were purchased from Jiangsu Aofu Biotechnology Co., Ltd.; sodium D-isoascorbate was purchased from Shanghai Zhongfeng Biotechnology Co., Ltd.; α-amylase was purchased from Beijing Solarbio Technology Co., Ltd.; saccharifying enzyme was purchased from Jiangsu Huace Biotechnology Co., Ltd.; amylopectin was purchased from Henan Guochen Biotechnology Co., Ltd.; lactic acid was purchased from Mingrui Group (Henan) Co., Ltd.; and brown algae oligosaccharides were purchased from Jiangsu Caiwei Biotechnology Co., Ltd.

[0027] Examples 1-3 provide a resistant starch (CZ01) extracted from green bananas and its application in pet food.

[0028] Example 1

[0029] A resistant starch (CZ01) extracted from green bananas is obtained by the following extraction method:

[0030] (1) Select green bananas that are free from mold and insects, peel them and cut them into 0.1cm slices. Control the mass ratio of green banana slices to compound color-protecting inhibitor solution to 1:10. Perform color protection treatment at 45℃ for 25min. After treatment, rinse with deionized water until neutral and drain the surface water to obtain pretreated green banana slices. The compound color-protecting inhibitor solution is composed of bamboo leaf flavonoids, sodium D-isoascorbate and deionized water in a mass ratio of 2:1:200.

[0031] (2) Mix the pretreated green banana slices with deionized water at a mass ratio of 1:4, add 0.05% of vitamin C to the mixture, and beat at high speed for 3 minutes at 8000 rpm under low temperature conditions of 2℃ to obtain green banana pulp.

[0032] (3) Add α-amylase to the green banana pulp, and hydrolyze it at 55℃ and pH 6.0 with a stirring speed of 200 rpm for 30 min. Then adjust the pH of the system to 4.0 with 5% citric acid aqueous solution, add the compound enzyme, and continue to maintain the temperature at 55℃ for 20 min. After the hydrolysis is completed, raise the temperature to 95℃ and inactivate the enzyme for 10 min. After cooling to room temperature, filter the mixture through a 100-mesh filter and centrifuge it at 3500 rpm for 15 min. Discard the supernatant and collect the lower starch precipitate. Wash the precipitate three times with deionized water to obtain crude starch precipitate. The mass ratio of green banana pulp, α-amylase and compound enzyme is 1000:2:1.5. The compound enzyme is composed of saccharifying enzyme and amylopectin in a mass ratio of 5:3.

[0033] (4) The crude starch precipitate and the modified liquid were mixed at a mass ratio of 1:4. The mixture was stirred at 200 rpm for 10 min at room temperature until it was homogeneous, and the pH of the system was adjusted to 4.5 with a 5% citric acid aqueous solution. The mixture was first allowed to stand at room temperature for 1 h to swell, and then placed at 4℃ for 4 h to refrigerate. After refrigeration, the mixture was vacuum dried at a vacuum degree of -0.08 MPa and a drying temperature of 45℃ until the moisture content was 10%. The mixture was then pulverized through a 100-mesh sieve to obtain resistant starch (CZ01). The modified liquid was composed of lactic acid, fucoidan oligosaccharide and deionized water in a mass ratio of 1:2:100.

[0034] A pet food, by weight percentage, comprises the following ingredients: 52% chicken breast, 8% chicken heart, 5% chicken liver, 8% egg, 5% carrot, 5% spinach, 3% kale, 1% fish oil, 1.5% parsley, 3% apple, 8% resistant starch (CZ01), and 0.5% chicory root powder.

[0035] A method for preparing pet food includes the following steps:

[0036] Remove tendons, fat, and impurities from chicken breast, chicken heart, and chicken liver, rinse thoroughly with water, and cut into 3mm diameter pieces. Peel and core carrots and apples, and cut into 4mm long and wide pieces. Remove yellow leaves, old roots, and impurities from spinach, kale, and parsley, and rinse thoroughly with water. Place all the above ingredients in a constant temperature pulverizer, control the pulverizing temperature at 20℃, and pulverize to 80 mesh. Set aside. Remove the shells from the eggs and beat them thoroughly until the egg liquid is smooth and uniform in texture. Set aside. Mix the chicken breast, chicken heart, chicken liver, carrots, apples, and eggs at 200 rpm at room temperature for 10 minutes until well mixed. Add resistant starch (CZ01), chicory root powder, and fish oil, and continue mixing at 200 rpm until well mixed. Control the homogenization pressure at 20 MPa and the homogenization time at 3 minutes. After homogenization, obtain the mixture. Dry the mixture at 50℃ until the moisture content is 10%. After drying, cool to room temperature, sterilize, and seal in packaging to obtain pet food.

[0037] Example 2

[0038] A resistant starch (CZ01) extracted from green bananas is obtained by the following extraction method:

[0039] (1) Select green bananas that are free from mold and insects, peel them and cut them into 0.15cm slices. Control the mass ratio of green banana slices to compound color-protecting inhibitor solution to 2:11. Perform color protection treatment at 48℃ for 28min. After treatment, rinse with deionized water until neutral and drain the surface water to obtain pretreated green banana slices. The compound color-protecting inhibitor solution is composed of bamboo leaf flavonoids, sodium D-isoascorbate and deionized water in a mass ratio of 2.5:1.1:250.

[0040] (2) Mix the pretreated green banana slices with deionized water at a mass ratio of 1:4.5, add 0.08% of vitamin C of the total mass of the mixture to the mixture, and beat at high speed for 4 minutes at a speed of 9000 rpm under low temperature conditions of 4℃ to obtain green banana pulp.

[0041] (3) Add α-amylase to the green banana pulp, and hydrolyze it at 60℃ and pH 6.5 with a stirring speed of 300 rpm for 35 min. Then adjust the pH of the system to 4.5 with 8% citric acid aqueous solution, add the compound enzyme, and continue to maintain the temperature at 60℃ for 25 min. After the hydrolysis is completed, raise the temperature to 98℃ and inactivate the enzyme for 12 min. After cooling to room temperature, filter the mixture through a 150 mesh filter and centrifuge it at 3800 rpm for 18 min. Discard the supernatant and collect the lower starch precipitate. Wash the precipitate with deionized water 4 times to obtain crude starch precipitate. The mass ratio of green banana pulp, α-amylase and compound enzyme is 1000:4:2. The compound enzyme is composed of saccharifying enzyme and amylopectin in a mass ratio of 6:3.5.

[0042] (4) The crude starch precipitate and the modified liquid were mixed at a mass ratio of 1.5:5. The mixture was stirred at 300 rpm for 20 min at room temperature until it was homogeneous, and the pH of the system was adjusted to 5 with an 8% citric acid aqueous solution. The mixture was first allowed to stand at room temperature for 1.5 h to swell, and then placed at 6℃ for 5 h to refrigerate. After refrigeration, the mixture was vacuum dried at a vacuum degree of -0.09 MPa and a drying temperature of 48℃ until the moisture content was 8%. The mixture was then pulverized through a 150-mesh sieve to obtain resistant starch (CZ01). The modified liquid was composed of lactic acid, fucoidan oligosaccharide and deionized water in a mass ratio of 3:4:100.

[0043] A pet food, by weight percentage, comprises the following ingredients: 41.5% chicken breast, 9% chicken heart, 8% chicken liver, 9% egg, 8% carrot, 6% spinach, 4% kale, 2% fish oil, 2.5% parsley, 4% apple, 5% resistant starch (CZ01), and 1% chicory root powder.

[0044] A method for preparing pet food includes the following steps:

[0045] Remove tendons, fat, and impurities from chicken breast, chicken heart, and chicken liver, rinse thoroughly with water, and cut into 5mm diameter pieces. Peel and core carrots and apples, and cut into 6mm long and wide pieces. Remove yellow leaves, old roots, and impurities from spinach, kale, and parsley, and rinse thoroughly with water. Place all the above ingredients in a constant temperature pulverizer, control the pulverizing temperature at 25℃, and pulverize to 90 mesh. Set aside. Remove the shells from the eggs and beat them thoroughly until the egg liquid is smooth and uniform in texture. Set aside. Mix the chicken breast, chicken heart, chicken liver, carrots, apples, and eggs at 300 rpm at room temperature for 20 minutes until well combined. Add resistant starch (CZ01), chicory root powder, and fish oil, and mix thoroughly at 300 rpm. Control the homogenization pressure at 25 MPa and the homogenization time at 4 minutes. After homogenization, obtain the mixture. Dry the mixture at 52℃ until the moisture content is 8%. After drying, cool to room temperature, sterilize, and seal in packaging to obtain pet food.

[0046] Example 3

[0047] A resistant starch (CZ01) extracted from green bananas is obtained by the following extraction method:

[0048] (1) Select green bananas that are free from mold and insects, peel them and cut them into 0.2cm slices. Control the mass ratio of green banana slices to compound color-protecting inhibitor solution to 3:12. Perform color protection treatment at 50℃ for 30min. After treatment, rinse with deionized water until neutral and drain the surface water to obtain pretreated green banana slices. The compound color-protecting inhibitor solution is composed of bamboo leaf flavonoids, sodium D-isoascorbate and deionized water in a mass ratio of 3:1.2:300.

[0049] (2) Mix the pretreated green banana slices with deionized water at a mass ratio of 1:5, add 0.1% of vitamin C to the mixture, and beat at 10000 rpm for 5 minutes at a low temperature of 6℃ to obtain green banana pulp.

[0050] (3) Add α-amylase to the green banana pulp, and hydrolyze it at a constant temperature of 400 rpm for 40 min with a stirring speed of 7.0 at a temperature of 65℃. Then adjust the pH of the system to 5.0 with a 10% citric acid aqueous solution, add the compound enzyme, and continue to maintain the temperature at 65℃ for 30 min. After the hydrolysis is completed, raise the temperature to 100℃ and inactivate the enzyme for 15 min. After cooling to room temperature, filter the mixture through a 200-mesh filter and centrifuge it at 4000 rpm for 20 min. Discard the supernatant and collect the lower starch precipitate. Wash the precipitate with deionized water 5 times to obtain crude starch precipitate. The mass ratio of green banana pulp, α-amylase and compound enzyme is 1000:5:3. The compound enzyme is composed of saccharifying enzyme and amylopectin in a mass ratio of 8:4.

[0051] (4) The crude starch precipitate and the modified liquid were mixed at a mass ratio of 2:6. The mixture was stirred at 400 rpm for 30 min at room temperature until homogeneous, and the starch suspension was obtained. The pH of the system was adjusted to 5.5 with a 10% citric acid aqueous solution. The mixture was allowed to stand at room temperature for 2 h to swell, and then placed at 8°C for 6 h to refrigerate. After refrigeration, the mixture was vacuum dried at a vacuum degree of -0.09 MPa and a drying temperature of 50°C until the moisture content was 5%. The mixture was then pulverized through a 200-mesh sieve to obtain resistant starch (CZ01). The modified liquid was composed of lactic acid, fucoidan oligosaccharide and deionized water in a mass ratio of 3:5:100.

[0052] A pet food, by weight percentage, comprises the following ingredients: 38% chicken breast, 8% chicken heart, 8% chicken liver, 10% egg, 9% carrot, 6% spinach, 5% kale, 3% fish oil, 3.5% parsley, 5% apple, 3% resistant starch (CZ01), and 1.5% chicory root powder.

[0053] A method for preparing pet food includes the following steps:

[0054] Remove tendons, fat, and impurities from chicken breast, chicken heart, and chicken liver, rinse thoroughly with water, and cut into 6mm diameter pieces. Peel and core carrots and apples, and cut into 8mm long and wide pieces. Remove yellow leaves, old roots, and impurities from spinach, kale, and parsley, and rinse thoroughly with water. Place all the above ingredients in a constant temperature pulverizer, control the pulverizing temperature at 30℃, and pulverize to 100 mesh. Set aside. Remove the shells from the eggs and beat them thoroughly until the egg liquid is smooth and uniform in texture. Set aside. Mix the chicken breast, chicken heart, chicken liver, carrots, apples, and eggs at 400 rpm at room temperature for 30 minutes until well combined. Add resistant starch (CZ01), chicory root powder, and fish oil, and mix thoroughly at 400 rpm. Control the homogenization pressure at 30 MPa and the homogenization time at 5 minutes. After homogenization, obtain the mixture. Dry the mixture at 55℃ until the moisture content is 5%. After drying, cool to room temperature, sterilize, and seal in packaging to obtain pet food.

[0055] Comparative Example 1

[0056] A resistant starch (CZ01) extracted from green bananas is obtained by the following extraction method:

[0057] (1) Select green bananas that are free from mold and insects, peel them and cut them into 0.1cm slices. Control the mass ratio of green banana slices to color-protecting inhibitor solution to 1:10. Perform color protection treatment at 45℃ for 25min. After treatment, rinse with deionized water until neutral and drain the surface water to obtain pretreated green banana slices. The composite color-protecting inhibitor solution is composed of sodium D-isoascorbate and deionized water in a mass ratio of 3:200.

[0058] (2) Mix the pretreated green banana slices with deionized water at a mass ratio of 1:4, add 0.05% of vitamin C to the mixture, and beat at high speed for 3 minutes at 8000 rpm under low temperature conditions of 2℃ to obtain green banana pulp.

[0059] (3) Add α-amylase to the green banana pulp, and hydrolyze it at 55℃ and pH 6.0 with a stirring speed of 200 rpm for 30 min. Then adjust the pH of the system to 4.0 with 5% citric acid aqueous solution, add the compound enzyme, and continue to maintain the temperature at 55℃ for 20 min. After the hydrolysis is completed, raise the temperature to 95℃ and inactivate the enzyme for 10 min. After cooling to room temperature, filter the mixture through a 100-mesh filter and centrifuge it at 3500 rpm for 15 min. Discard the supernatant and collect the lower starch precipitate. Wash the precipitate three times with deionized water to obtain crude starch precipitate. The mass ratio of green banana pulp, α-amylase and compound enzyme is 1000:2:1.5. The compound enzyme is composed of saccharifying enzyme and amylopectin in a mass ratio of 5:3.

[0060] (4) The crude starch precipitate and the modified liquid were mixed at a mass ratio of 1:4. The mixture was stirred at 200 rpm for 10 min at room temperature until it was homogeneous, and the pH of the system was adjusted to 4.5 with a 5% citric acid aqueous solution. The mixture was first allowed to stand at room temperature for 1 h to swell, and then placed at 4℃ for 4 h to refrigerate. After refrigeration, the mixture was vacuum dried at a vacuum degree of -0.08 MPa and a drying temperature of 45℃ until the moisture content was 10%. The mixture was then pulverized through a 100-mesh sieve to obtain resistant starch (CZ01). The modified liquid was composed of lactic acid, fucoidan oligosaccharide and deionized water in a mass ratio of 1:2:100.

[0061] A pet food, by weight percentage, comprises the following ingredients: 52% chicken breast, 8% chicken heart, 5% chicken liver, 8% egg, 5% carrot, 5% spinach, 3% kale, 1% fish oil, 1.5% parsley, 3% apple, 8% resistant starch, and 0.5% chicory root powder.

[0062] A method for preparing pet food includes the following steps:

[0063] Remove tendons, fat, and impurities from chicken breast, chicken heart, and chicken liver, rinse thoroughly with water, and cut into 3mm diameter pieces. Peel and core carrots and apples, and cut into 4mm long and wide pieces. Remove yellow leaves, old roots, and impurities from spinach, kale, and parsley, and rinse thoroughly with water. Place all the above ingredients in a constant temperature pulverizer, control the pulverizing temperature at 20℃, and pulverize to 80 mesh. Set aside. Remove the shells from the eggs and beat them thoroughly until the egg liquid is smooth and uniform in texture. Set aside. Mix the chicken breast, chicken heart, chicken liver, carrots, apples, and eggs at 200 rpm at room temperature for 10 minutes until well combined. Add resistant starch (CZ01), chicory root powder, and fish oil, and mix thoroughly at 200 rpm. Control the homogenization pressure at 20 MPa and the homogenization time at 3 minutes. After homogenization, obtain the mixture. Dry the mixture at 50℃ until the moisture content is 10%. After drying, cool to room temperature, sterilize, and seal in packaging to obtain pet food.

[0064] Comparative Example 2

[0065] A resistant starch (CZ01) extracted from green bananas is obtained by the following extraction method:

[0066] (1) Select green bananas that are free from mold and insects, peel them and cut them into 0.1cm slices. Control the mass ratio of green banana slices to color-protecting inhibitor solution to 1:10. Perform color protection treatment at 45℃ for 25min. After treatment, rinse with deionized water until neutral and drain the surface water to obtain pretreated green banana slices. The composite color-protecting inhibitor solution is composed of bamboo leaf flavonoids and deionized water in a mass ratio of 3:200.

[0067] (2) Mix the pretreated green banana slices with deionized water at a mass ratio of 1:4, add 0.05% of vitamin C to the mixture, and beat at high speed for 3 minutes at 8000 rpm under low temperature conditions of 2℃ to obtain green banana pulp.

[0068] (3) Add α-amylase to the green banana pulp, and hydrolyze it at 55℃ and pH 6.0 with a stirring speed of 200 rpm for 30 min. Then adjust the pH of the system to 4.0 with 5% citric acid aqueous solution, add the compound enzyme, and continue to maintain the temperature at 55℃ for 20 min. After the hydrolysis is completed, raise the temperature to 95℃ and inactivate the enzyme for 10 min. After cooling to room temperature, filter the mixture through a 100-mesh filter and centrifuge it at 3500 rpm for 15 min. Discard the supernatant and collect the lower starch precipitate. Wash the precipitate three times with deionized water to obtain crude starch precipitate. The mass ratio of green banana pulp, α-amylase and compound enzyme is 1000:2:1.5. The compound enzyme is composed of saccharifying enzyme and amylopectin in a mass ratio of 5:3.

[0069] (4) The crude starch precipitate and the modified liquid were mixed at a mass ratio of 1:4. The mixture was stirred at 200 rpm for 10 min at room temperature until it was homogeneous, and the pH of the system was adjusted to 4.5 with a 5% citric acid aqueous solution. The mixture was first allowed to stand at room temperature for 1 h to swell, and then placed at 4℃ for 4 h to refrigerate. After refrigeration, the mixture was vacuum dried at a vacuum degree of -0.08 MPa and a drying temperature of 45℃ until the moisture content was 10%. The mixture was then pulverized through a 100-mesh sieve to obtain resistant starch (CZ01). The modified liquid was composed of lactic acid, fucoidan oligosaccharide and deionized water in a mass ratio of 1:2:100.

[0070] A pet food, by weight percentage, comprises the following ingredients: 52% chicken breast, 8% chicken heart, 5% chicken liver, 8% egg, 5% carrot, 5% spinach, 3% kale, 1% fish oil, 1.5% parsley, 3% apple, 8% resistant starch (CZ01), and 0.5% chicory root powder.

[0071] A method for preparing pet food includes the following steps:

[0072] Remove tendons, fat, and impurities from chicken breast, chicken heart, and chicken liver, rinse thoroughly with water, and cut into 3mm diameter pieces. Peel and core carrots and apples, and cut into 4mm long and wide pieces. Remove yellow leaves, old roots, and impurities from spinach, kale, and parsley, and rinse thoroughly with water. Place all the above ingredients in a constant temperature pulverizer, control the pulverizing temperature at 20℃, and pulverize to 80 mesh. Set aside. Remove the shells from the eggs and beat them thoroughly until the egg liquid is smooth and uniform in texture. Set aside. Mix the chicken breast, chicken heart, chicken liver, carrots, apples, and eggs at 200 rpm at room temperature for 10 minutes until well combined. Add resistant starch (CZ01), chicory root powder, and fish oil, and mix thoroughly at 200 rpm. Control the homogenization pressure at 20 MPa and the homogenization time at 3 minutes. After homogenization, obtain the mixture. Dry the mixture at 50℃ until the moisture content is 10%. After drying, cool to room temperature, sterilize, and seal in packaging to obtain pet food.

[0073] Comparative Example 3

[0074] A resistant starch (CZ01) extracted from green bananas is obtained by the following extraction method:

[0075] (1) Select green bananas that are free from mold and insects, peel them and cut them into 0.1cm slices. Control the mass ratio of green banana slices to compound color-protecting inhibitor solution to 1:10. Perform color protection treatment at 45℃ for 25min. After treatment, rinse with deionized water until neutral and drain the surface water to obtain pretreated green banana slices. The compound color-protecting inhibitor solution is composed of bamboo leaf flavonoids, sodium D-isoascorbate and deionized water in a mass ratio of 2:1:200.

[0076] (2) Mix the pretreated green banana slices with deionized water at a mass ratio of 1:4, add 0.05% of vitamin C to the mixture, and beat at high speed for 3 minutes at 8000 rpm under low temperature conditions of 2℃ to obtain green banana pulp.

[0077] (3) Add α-amylase and complex enzyme to green banana pulp. At a hydrolysis temperature of 55℃ and a pH of 6.0, stir at a constant temperature of 200 rpm for 50 min. After hydrolysis, raise the temperature to 95℃ and inactivate the enzyme for 10 min. After cooling to room temperature, filter the mixture through a 100-mesh filter and centrifuge at 3500 rpm for 15 min. Discard the supernatant and collect the lower starch precipitate. Wash the precipitate three times with deionized water to obtain crude starch precipitate. The mass ratio of green banana pulp, α-amylase and complex enzyme is 1000:2:1.5. The complex enzyme is composed of saccharifying enzyme and amylopectin in a mass ratio of 5:3.

[0078] (4) The crude starch precipitate and the modified liquid were mixed at a mass ratio of 1:4. The mixture was stirred at 200 rpm for 10 min at room temperature until it was homogeneous, and the pH of the system was adjusted to 4.5 with a 5% citric acid aqueous solution. The mixture was first allowed to stand at room temperature for 1 h to swell, and then placed at 4℃ for 4 h to refrigerate. After refrigeration, the mixture was vacuum dried at a vacuum degree of -0.08 MPa and a drying temperature of 45℃ until the moisture content was 10%. The mixture was then pulverized through a 100-mesh sieve to obtain resistant starch (CZ01). The modified liquid was composed of lactic acid, fucoidan oligosaccharide and deionized water in a mass ratio of 1:2:100.

[0079] A pet food, by weight percentage, comprises the following ingredients: 52% chicken breast, 8% chicken heart, 5% chicken liver, 8% egg, 5% carrot, 5% spinach, 3% kale, 1% fish oil, 1.5% parsley, 3% apple, 8% resistant starch (CZ01), and 0.5% chicory root powder.

[0080] A method for preparing pet food includes the following steps:

[0081] Remove tendons, fat, and impurities from chicken breast, chicken heart, and chicken liver, rinse thoroughly with water, and cut into 3mm diameter pieces. Peel and core carrots and apples, and cut into 4mm long and wide pieces. Remove yellow leaves, old roots, and impurities from spinach, kale, and parsley, and rinse thoroughly with water. Place all the above ingredients in a constant temperature pulverizer, control the pulverizing temperature at 20℃, and pulverize to 80 mesh. Set aside. Remove the shells from the eggs and beat them thoroughly until the egg liquid is smooth and uniform in texture. Set aside. Mix the chicken breast, chicken heart, chicken liver, carrots, apples, and eggs at 200 rpm at room temperature for 10 minutes until well combined. Add resistant starch (CZ01), chicory root powder, and fish oil, and mix thoroughly at 200 rpm. Control the homogenization pressure at 20 MPa and the homogenization time at 3 minutes. After homogenization, obtain the mixture. Dry the mixture at 50℃ until the moisture content is 10%. After drying, cool to room temperature, sterilize, and seal in packaging to obtain pet food.

[0082] Comparative Example 4

[0083] A resistant starch (CZ01) extracted from green bananas is obtained by the following extraction method:

[0084] (1) Select green bananas that are free from mold and insects, peel them and cut them into 0.1cm slices. Control the mass ratio of green banana slices to compound color-protecting inhibitor solution to 1:10. Perform color protection treatment at 45℃ for 25min. After treatment, rinse with deionized water until neutral and drain the surface water to obtain pretreated green banana slices. The compound color-protecting inhibitor solution is composed of bamboo leaf flavonoids, sodium D-isoascorbate and deionized water in a mass ratio of 2:1:200.

[0085] (2) Mix the pretreated green banana slices with deionized water at a mass ratio of 1:4, add 0.05% of vitamin C to the mixture, and beat at high speed for 3 minutes at 8000 rpm under low temperature conditions of 2℃ to obtain green banana pulp.

[0086] (3) Add α-amylase to the green banana pulp, and hydrolyze it at 55℃ and pH 6.0 with a stirring speed of 200 rpm for 30 min. Then adjust the pH of the system to 4.0 with 5% citric acid aqueous solution, add amylopectin, keep the temperature at 55℃ and hydrolyze for 20 min. After hydrolysis, raise the temperature to 95℃ and inactivate the enzyme for 10 min. After cooling to room temperature, filter the mixture through a 100-mesh filter and centrifuge it at 3500 rpm for 15 min. Discard the supernatant and collect the lower starch precipitate. Wash the precipitate three times with deionized water to obtain crude starch precipitate. The mass ratio of green banana pulp, α-amylase and amylopectin is 1000:2:1.5.

[0087] (4) The crude starch precipitate and the modified liquid were mixed at a mass ratio of 1:4. The mixture was stirred at 200 rpm for 10 min at room temperature until it was homogeneous, and the pH of the system was adjusted to 4.5 with a 5% citric acid aqueous solution. The mixture was first allowed to stand at room temperature for 1 h to swell, and then placed at 4℃ for 4 h to refrigerate. After refrigeration, the mixture was vacuum dried at a vacuum degree of -0.08 MPa and a drying temperature of 45℃ until the moisture content was 10%. The mixture was then pulverized through a 100-mesh sieve to obtain resistant starch (CZ01). The modified liquid was composed of lactic acid, fucoidan oligosaccharide and deionized water in a mass ratio of 1:2:100.

[0088] A pet food, by weight percentage, comprises the following ingredients: 52% chicken breast, 8% chicken heart, 5% chicken liver, 8% egg, 5% carrot, 5% spinach, 3% kale, 1% fish oil, 1.5% parsley, 3% apple, 8% resistant starch (CZ01), and 0.5% chicory root powder.

[0089] A method for preparing pet food includes the following steps:

[0090] Remove tendons, fat, and impurities from chicken breast, chicken heart, and chicken liver, rinse thoroughly with water, and cut into 3mm diameter pieces. Peel and core carrots and apples, and cut into 4mm long and wide pieces. Remove yellow leaves, old roots, and impurities from spinach, kale, and parsley, and rinse thoroughly with water. Place all the above ingredients in a constant temperature pulverizer, control the pulverizing temperature at 20℃, and pulverize to 80 mesh. Set aside. Remove the shells from the eggs and beat them thoroughly until the egg liquid is smooth and uniform in texture. Set aside. Mix the chicken breast, chicken heart, chicken liver, carrots, apples, and eggs at 200 rpm at room temperature for 10 minutes until well combined. Add resistant starch (CZ01), chicory root powder, and fish oil, and mix thoroughly at 200 rpm. Control the homogenization pressure at 20 MPa and the homogenization time at 3 minutes. After homogenization, obtain the mixture. Dry the mixture at 50℃ until the moisture content is 10%. After drying, cool to room temperature, sterilize, and seal in packaging to obtain pet food.

[0091] Comparative Example 5

[0092] A resistant starch (CZ01) extracted from green bananas is obtained by the following extraction method:

[0093] (1) Select green bananas that are free from mold and insects, peel them and cut them into 0.1cm slices. Control the mass ratio of green banana slices to compound color-protecting inhibitor solution to 1:10. Perform color protection treatment at 45℃ for 25min. After treatment, rinse with deionized water until neutral and drain the surface water to obtain pretreated green banana slices. The compound color-protecting inhibitor solution is composed of bamboo leaf flavonoids, sodium D-isoascorbate and deionized water in a mass ratio of 2:1:200.

[0094] (2) Mix the pretreated green banana slices with deionized water at a mass ratio of 1:4, add 0.05% of vitamin C to the mixture, and beat at high speed for 3 minutes at 8000 rpm under low temperature conditions of 2℃ to obtain green banana pulp.

[0095] (3) Add α-amylase to the green banana pulp, and hydrolyze it at 55℃ and pH 6.0 with a stirring speed of 200 rpm for 30 min. Then adjust the pH of the system to 4.0 with 5% citric acid aqueous solution, add saccharifying enzyme, keep the temperature at 55℃ and hydrolyze for 20 min. After the hydrolysis is completed, raise the temperature to 95℃ and inactivate the enzyme for 10 min. After cooling to room temperature, filter it through a 100-mesh filter and centrifuge it at 3500 rpm for 15 min. Discard the supernatant and collect the lower starch precipitate. Wash the precipitate three times with deionized water to obtain crude starch precipitate. The mass ratio of green banana pulp, α-amylase and saccharifying enzyme is 1000:2:1.5.

[0096] (4) The crude starch precipitate and the modified liquid were mixed at a mass ratio of 1:4. The mixture was stirred at 200 rpm for 10 min at room temperature until it was homogeneous, and the pH of the system was adjusted to 4.5 with a 5% citric acid aqueous solution. The mixture was first allowed to stand at room temperature for 1 h to swell, and then placed at 4℃ for 4 h to refrigerate. After refrigeration, the mixture was vacuum dried at a vacuum degree of -0.08 MPa and a drying temperature of 45℃ until the moisture content was 10%. The mixture was then pulverized through a 100-mesh sieve to obtain resistant starch (CZ01). The modified liquid was composed of lactic acid, fucoidan oligosaccharide and deionized water in a mass ratio of 1:2:100.

[0097] A pet food, by weight percentage, comprises the following ingredients: 52% chicken breast, 8% chicken heart, 5% chicken liver, 8% egg, 5% carrot, 5% spinach, 3% kale, 1% fish oil, 1.5% parsley, 3% apple, 8% resistant starch (CZ01), and 0.5% chicory root powder.

[0098] A method for preparing pet food includes the following steps:

[0099] Remove tendons, fat, and impurities from chicken breast, chicken heart, and chicken liver, rinse thoroughly with water, and cut into 3mm cubes. Peel and core carrots and apples, and cut into 4mm pieces. Remove yellow leaves, tough roots, and impurities from spinach, kale, and parsley, and rinse thoroughly with water. Place all the above ingredients in a constant temperature pulverizer, control the pulverizing temperature at 20℃, and pulverize to 80 mesh for a puree. Set aside. Remove the shells from the eggs and beat them thoroughly until the egg liquid is smooth and uniform in texture. Set aside. Mix the chicken breast, chicken heart, chicken liver, carrots, apples, and eggs at 200 rpm at room temperature for 10 minutes until well combined. Add resistant starch (CZ01), chicory root powder, and fish oil, and mix at 200 rpm until well combined. Control the homogenization pressure at 20 MPa and the homogenization time at 3 minutes. After homogenization, obtain the mixture. Dry the mixture at 50℃ until the moisture content is 10%. After drying, cool to room temperature, sterilize, and seal in packaging to obtain pet food.

[0100] Comparative Example 6

[0101] A resistant starch (CZ01) extracted from green bananas is obtained by the following extraction method:

[0102] (1) Select green bananas that are free from mold and insects, peel them and cut them into 0.1cm slices. Control the mass ratio of green banana slices to compound color-protecting inhibitor solution to 1:10. Perform color protection treatment at 45℃ for 25min. After treatment, rinse with deionized water until neutral and drain the surface water to obtain pretreated green banana slices. The compound color-protecting inhibitor solution is composed of bamboo leaf flavonoids, sodium D-isoascorbate and deionized water in a mass ratio of 2:1:200.

[0103] (2) Mix the pretreated green banana slices with deionized water at a mass ratio of 1:4, add 0.05% of vitamin C to the mixture, and beat at high speed for 3 minutes at 8000 rpm under low temperature conditions of 2℃ to obtain green banana pulp.

[0104] (3) Add α-amylase to the green banana pulp, and hydrolyze it at 55℃ and pH 6.0 with a stirring speed of 200 rpm for 30 min. Then adjust the pH of the system to 4.0 with 5% citric acid aqueous solution, add the compound enzyme, and continue to maintain the temperature at 55℃ for 20 min. After the hydrolysis is completed, raise the temperature to 95℃ and inactivate the enzyme for 10 min. After cooling to room temperature, filter the mixture through a 100-mesh filter and centrifuge it at 3500 rpm for 15 min. Discard the supernatant and collect the lower starch precipitate. Wash the precipitate three times with deionized water to obtain crude starch precipitate. The mass ratio of green banana pulp, α-amylase and compound enzyme is 1000:2:1.5. The compound enzyme is composed of saccharifying enzyme and amylopectin in a mass ratio of 5:3.

[0105] (4) The crude starch precipitate and the modified liquid were mixed at a mass ratio of 1:4. The mixture was stirred at 200 rpm for 10 min at room temperature until it was homogeneous, and the pH of the system was adjusted to 4.5 with a 5% citric acid aqueous solution. The mixture was allowed to stand at room temperature for 5 h to swell. It was then vacuum dried at a vacuum degree of -0.08 MPa and a drying temperature of 45 °C until the moisture content was 10%. The mixture was then pulverized through a 100-mesh sieve to obtain resistant starch (CZ01). The modified liquid was composed of lactic acid, fucoidan oligosaccharide and deionized water in a mass ratio of 1:2:100.

[0106] A pet food, by weight percentage, comprises the following ingredients: 52% chicken breast, 8% chicken heart, 5% chicken liver, 8% egg, 5% carrot, 5% spinach, 3% kale, 1% fish oil, 1.5% parsley, 3% apple, 8% resistant starch (CZ01), and 0.5% chicory root powder.

[0107] A method for preparing pet food includes the following steps:

[0108] Remove tendons, fat, and impurities from chicken breast, chicken heart, and chicken liver, rinse thoroughly with water, and cut into 3mm cubes. Peel and core carrots and apples, and cut into 4mm pieces. Remove yellow leaves, tough roots, and impurities from spinach, kale, and parsley, and rinse thoroughly with water. Place all the above ingredients in a constant temperature pulverizer, control the pulverizing temperature at 20℃, and pulverize to 80 mesh for a puree. Set aside. Remove the shells from the eggs and beat them thoroughly until the egg liquid is smooth and uniform in texture. Set aside. Mix the chicken breast, chicken heart, chicken liver, carrots, apples, and eggs at 200 rpm at room temperature for 10 minutes until well combined. Add resistant starch (CZ01), chicory root powder, and fish oil, and mix at 200 rpm until well combined. Control the homogenization pressure at 20 MPa and the homogenization time at 3 minutes. After homogenization, obtain the mixture. Dry the mixture at 50℃ until the moisture content is 10%. After drying, cool to room temperature, sterilize, and seal in packaging to obtain pet food.

[0109] Performance testing

[0110] The comprehensive properties of the resistant starch (CZ01) prepared in Examples 1-3 and Comparative Examples 1-6, as well as the pet food, were tested respectively, as follows:

[0111] Resistant starch yield: The content of resistant starch in the resistant starch sample was determined using the AOAC 991.43 standard method;

[0112] Resistant starch yield (%) = (dry weight of extracted resistant starch / dry weight of green banana raw material) × 100%;

[0113] Water-holding capacity test: Weigh 1.0 g of oven-dry resistant starch sample, place it in a centrifuge tube, add 20 mL of deionized water, let it stand at room temperature for 30 min to swell, centrifuge at 3500 rpm for 20 min, discard the supernatant, weigh the wet weight of the precipitate, and obtain the mass of wet starch.

[0114] Water-holding capacity (g / g) = (Wet starch mass − Oven-dry resistant starch mass) / Oven-dry resistant starch mass;

[0115] Expansion determination: Weigh 1.0g of oven-dried resistant starch sample, add 50mL of deionized water, keep warm in a 90℃ water bath for 30min, cool to room temperature, let stand and separate into layers, and read the sedimentation volume of the lower starch layer to obtain the starch sedimentation volume.

[0116] Expansion (mL / g) = Starch sedimentation volume / Oven-dry resistant starch mass;

[0117] An in vitro two-step digestion method was used to simulate the digestive physiological environment of the stomach and small intestine in dogs and cats. The contents of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) in resistant starch samples were determined, and the in vitro digestibility of starch was calculated to characterize the starch's resistance to digestion and its slow-release energy supply characteristics. The specific determination steps are as follows:

[0118] Accurately weigh 200 mg of oven-dry resistant starch sample and place it in a 50 mL centrifuge tube. Add 15 mL of deionized water, shake to mix, and prepare a homogeneous starch suspension. Adjust the pH of the suspension to 2.5 using 0.1 mol / L dilute hydrochloric acid, and add the prepared pepsin solution to bring the final pepsin concentration in the system to 2000 U / mL. Place the centrifuge tube in a constant temperature water bath shaker, set the temperature to 37℃ and the shaking rate to 120 rpm, and perform constant temperature shaking digestion for 2 hours to simulate the acidic digestive environment of the canine and feline stomachs. After gastric digestion, adjust the pH of the system to 7.5 using 0.1 mol / L sodium hydroxide solution, and then add trypsin and pancreatic amylase sequentially to bring the trypsin concentration in the system to 2000 U / mL. The final concentration of pancreatic amylase was 1500 U / mL, and the final concentration was 1000 U / mL. The temperature was maintained at 37℃, and the shaking rate at 120 rpm for 4 hours to simulate the neutral digestive environment of the canine and feline small intestine. Samples were taken at 0 min, 20 min, 120 min, and 360 min, 1.0 mL each time. Enzymatic digestion was terminated by boiling in a 100℃ water bath for 5 min. After cooling to room temperature, the sample was centrifuged at 8000 rpm for 10 min, and the supernatant was collected. The glucose production was determined using the DNS method. The contents of rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) were calculated based on the glucose production. The calculation formula is as follows:

[0119] Rapidly digestible starch (RDS, %) = Mass of hydrolyzed starch in 0-20 min of digestion / Total starch mass in the sample × 100%;

[0120] Slowly digested starch (SDS, %) = Mass of hydrolyzed starch after 120-360 min of digestion / Total starch mass of sample × 100%;

[0121] Resistant starch (RS, %) = (total starch mass − total mass of digested and hydrolyzed starch) / total starch mass of sample × 100%;

[0122] Starch in vitro digestibility (%) = (RDS + SDS) / total starch mass × 100%.

[0123] Glycemic index (GI): The glycemic index of resistant starch samples was determined using an in vitro starch hydrolysis kinetic method, simulating the process of carbohydrate hydrolysis and absorption in dogs and cats. White bread was used as a control sample to determine the smoothness of the glycemic rise. The lower the GI value, the better the blood sugar control effect. The specific determination steps are as follows:

[0124] Accurately weigh 500 mg of oven-dry resistant starch sample and place it in an Erlenmeyer flask. Add 20 mL of 0.05 mol / L phosphate buffer (pH=6.8), stir well, and preheat in a 37℃ water bath for 10 min. Add a complex digestive enzyme (α-amylase + saccharifying enzyme) to the system and hydrolyze at 37℃ and 150 rpm with constant temperature shaking. Accurately take 1 mL samples at 0 min, 15 min, 30 min, 60 min, 90 min, and 120 min, respectively, inactivate the starch in a 100℃ boiling water bath for 5 min, cool to room temperature, centrifuge at 10000 rpm for 8 min, collect the supernatant, and determine the amount of glucose produced in the supernatant at each time point using the DNS method. Plot the starch hydrolysis kinetic curve of the sample. Use an equal mass of white bread as a reference sample, perform the above operation simultaneously, and plot the control hydrolysis kinetic curve. Calculate the area under the starch hydrolysis curve (AUC) of the sample and white bread within 0-120 min.

[0125] The calculation formula is: GI = Area under the hydrolysis curve of the sample / Area under the hydrolysis curve of the white bread × 100;

[0126] Glycemic index (GI) criteria: GI < 55 is considered a low glycemic index food; 55 ≤ GI ≤ 70 is considered a medium glycemic index food; GI > 70 is considered a high glycemic index food.

[0127] Intestinal health and fecal indicators: Healthy adult dogs / cats were selected and fed in groups with the pet food prepared in each example and comparative example. They had free access to food and water for 28 consecutive days. The fecal scoring criteria (1-5 level scoring method) were as follows:

[0128] Grade 1: Stools are dry and hard, consisting of individual hard particles, and defecation is difficult;

[0129] Grade 2: The stool is formed and relatively dry, with a firm texture and clear edges;

[0130] Level 3: The stool is of moderate softness and firmness, well-formed, and has suitable moisture, which is the ideal state of healthy stool;

[0131] Grade 4: Stool is soft, unformed, with blurred edges and slightly loose;

[0132] Grade 5: The stool is thin and watery, with obvious diarrhea and unformed stool;

[0133] The fecal scores of each group of experimental animals were recorded daily, and the average fecal score and the fecal formation qualification rate were calculated. At the same time, the presence of soft stool, diarrhea, bloating and other intestinal discomfort was observed to evaluate the effect of pet food on protecting the intestines and improving the intestinal metabolism of pets.

[0134] The specific test results are shown in Table 1.

[0135] Table 1. Comprehensive performance parameters of resistant starch (CZ01) and pet food in Examples 1-3 and Comparative Examples 1-6.

[0136]

[0137] As shown in Table 1, the resistant starch (CZ01) prepared in Examples 1-3 of this application exhibits significantly better resistant starch yield, water-holding capacity, and swelling capacity than the comparative examples. Furthermore, it has lower RDS and SDS content, significantly higher RS ​​content, and a marked decrease in in vitro digestibility and GI value, classifying it as a low-glycemic starch. This allows it to slow down rapid carbohydrate absorption and stabilize pet blood sugar levels. Additionally, pet food supplemented with this resistant starch (CZ01) maintains the average fecal score within the ideal range after feeding, with a high rate of qualified fecal formation and no intestinal discomfort such as soft stools, diarrhea, or bloating. This indicates that the extraction process of this application can efficiently prepare high-quality resistant starch, which, when applied to pet food, can effectively regulate intestinal metabolism and improve fecal condition, providing both blood sugar control and intestinal protection benefits.

[0138] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A resistant starch extracted from green bananas, characterized in that, It was obtained by the following extraction method: (1) Select green bananas that are free from mold and insects, peel them and slice them. Use a compound color-protecting inhibitor solution for constant temperature color protection treatment. After treatment, rinse with deionized water and drain the surface moisture to obtain pre-treated green banana slices: (2) Mix the pretreated green banana slices with deionized water, add antioxidants, and pulp under low temperature conditions to obtain green banana pulp; (3) Add α-amylase to the green banana pulp and hydrolyze at a constant temperature for 30-40 min; then adjust the pH of the system to 4.0-5.0, add the compound enzyme and continue to hydrolyze at a constant temperature for 20-30 min; after the hydrolysis is completed, inactivate the enzyme at high temperature, cool, filter and centrifuge in sequence, discard the supernatant, collect the lower precipitate, wash the precipitate with deionized water to obtain crude starch precipitate; (4) Mix the crude starch precipitate and the modified liquid, stir evenly to obtain a starch suspension, adjust the pH of the system to 4.5-5.5; let it stand at room temperature for 1-2 hours to swell, then place it at 4-8℃ for 4-6 hours to regenerate; after regeneration, vacuum dry until the moisture content is ≤10%, pulverize and sieve to obtain resistant starch.

2. The resistant starch extracted from green bananas according to claim 1, characterized in that, In step (1), the compound color-protecting inhibitor solution is composed of bamboo leaf flavonoids, sodium D-isoascorbate and deionized water in a mass ratio of 2-3:1-1.2:200-300.

3. The resistant starch extracted from green bananas according to claim 1, characterized in that, In step (3), the mass ratio of green banana pulp, α-amylase and complex enzyme is 1000:2-5:1.5-3.

4. The resistant starch extracted from green bananas according to claim 1, characterized in that, In step (3), the complex enzyme is composed of saccharifying enzyme and amylopectin in a mass ratio of 5-8:3-4.

5. The resistant starch extracted from green bananas according to claim 4, characterized in that, In step (3), the α-amylase is a thermostable α-amylase with an enzyme activity ≥2000U / g.

6. The resistant starch extracted from green bananas according to claim 1, characterized in that, In step (3), the isothermal enzymatic hydrolysis temperature is 55-65℃ and the pH value is 6.0-7.0; the high-temperature enzyme inactivation temperature is 95-100℃ and the high-temperature enzyme inactivation time is 10-15min.

7. The resistant starch extracted from green bananas according to claim 1, characterized in that, In step (4), the mass ratio of crude starch precipitate to modified liquid is 1-2:4-6.

8. The resistant starch extracted from green bananas according to claim 1, characterized in that, In step (4), the modified liquid is composed of lactic acid, brown algae oligosaccharide and deionized water in a mass ratio of 1-3:2-5:

100.

9. The application of the resistant starch extracted from green bananas as described in any one of claims 1-8 in the preparation of sugar-controlled and gut-protecting pet food.

10. The application of the resistant starch extracted from green bananas as described in claim 9 in the preparation of sugar-controlled and gut-protecting pet food, characterized in that... The raw material components of the pet food, by weight percentage, include: 30-52% chicken breast, 8-10% chicken heart, 5-10% chicken liver, 8-10% egg, 5-10% carrot, 5-7% spinach, 3-5% kale, 1-3% fish oil, 1.5-3.5% parsley, 3-5% apple, 3-8% resistant starch, and 0.5-1.5% chicory root powder.

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