Biological feed fermentation method based on potato byproducts and mulberry resources

Abstract

The invention discloses a biological feed fermentation method based on potato byproducts and mulberry resources, belongs to the technical field of feed processing, and aims at solving the problems that the utilization rate of potato byproducts such as sweet potato vines and mulberry resources such as mulberry branches and leaves is low, and the digestibility of animals is poor due to the high content of antinutritional factors such as tannin in feed. The method comprises the following steps: weighing mulberry branches and leaves, sweet potatoes and sweet potato vines according to a fresh weight ratio, wherein the mixing ratio of the mulberry branches and leaves to the sweet potatoes to the sweet potato vines is (0.5-2): (0.5-2): (0-2); bagasse is added; spraying the mulberry twig bark water extract; adding a mulberry leaf water extract aqueous solution and uniformly mixing; adding a compound fermentation bacterium agent which is prepared from tannin degrading bacteria, potato starch decomposing bacteria and cellulose decomposing bacteria according to the viable count ratio of (1.5 to 2.5) to (0.8 to 1.2) to (0.8 to 1.2); after vacuum sealing, fermentation is performed for 30-40 days at 25-30 DEG C, tannin is effectively degraded, starch and fibers are decomposed, and the nutritional value of the feed is improved. The obtained biological feed is balanced in nutrition, easy to digest and mainly used for feeding livestock and poultry such as pigs and cattle, resource utilization of agricultural waste is achieved, and breeding benefits are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of feed processing, and in particular relates to a biological feed fermentation method based on tuber by-products and mulberry resources. Background Art

[0002] In the field of feed processing, the utilization of potato by-products (such as sweet potato vines) and mulberry resources (such as mulberry branches and leaves) has significant limitations. Although these agricultural wastes contain potential nutritional value, their practical application faces two challenges: Low resource utilization: Fresh feed has a complex fiber structure and a tough texture, making it less palatable when fed directly, resulting in a large amount of resources not being effectively utilized; Anti-nutritional factors restrict digestion and absorption: Mulberry branches and leaves and sweet potato vines have a high tannin content (up to 5%-8% of dry matter). Their protein-binding properties significantly reduce the bioavailability of feed protein. At the same time, the starch and fiber wrapping structure of potatoes hinders the action of animal digestive enzymes, further affecting the release of nutrients.

[0003] Previous attempts to degrade anti-nutritional factors through microbial fermentation have also encountered bottlenecks. Tannins have a significant inhibitory effect on microbial activity, and conventional single bacterial species are unable to achieve efficient degradation of tannins and simultaneous decomposition of starch and fiber. The lack of synergy among the bacterial communities during the fermentation process can easily lead to incomplete degradation or excessively long fermentation cycles (usually more than 50 days), which not only increases energy consumption costs but also makes it difficult to achieve large-scale application.

[0004] The above problems have long restricted the efficient conversion of this type of agricultural waste in the feed field. Summary of the Invention

[0005] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0006] In order to achieve these purposes and other advantages according to the present invention, a bio-feed fermentation method based on tuber by-products and mulberry resources is provided, comprising the following steps: S1. Weigh mulberry branches and leaves, sweet potatoes, and sweet potato vines according to their fresh weight ratio, with a mixing ratio of mulberry branches and leaves: sweet potatoes: sweet potato vines = 0.5~2:0.5~2:0~2; S2. Adding bagasse to the raw material of step S1 in an amount of 3-5% of the total fresh weight of the raw material; S3, spraying 2-3 g / L of mulberry bark water extract at a spraying rate of 10-15 mL / kg of raw material; S4, add 3-5 g / L of mulberry leaf water extract aqueous solution and mix well; S5. Add 0.5-1.0% of the total fresh weight of the raw materials as a composite fermentation agent, wherein the composite fermentation agent includes tannin-degrading bacteria, potato starch-degrading bacteria, and fiber-degrading bacteria at a ratio of viable bacteria of 1.5-2.5:0.8-1.2:0.8-1.2; S6. Vacuum seal and ferment at 25-30℃ for 30-40 days.

[0007] Preferably, the preparation of the mulberry bark water extract comprises the following steps: Grind the dried mulberry bark into 20-40 mesh, and mix the ground mulberry bark with water at a mass ratio of 1:10-15; Adding 0.5-1.5% of the dry weight of mulberry bark complex enzyme preparation, the complex enzyme preparation is composed of cellulase, pectinase and β-glucosidase in an enzyme activity ratio of 3-5:2-4:1; Enzyme hydrolysis at 45-55°C and pH 4.5-5.5 for 1-2 hours to obtain an enzymatic hydrolyzate; The enzymatic hydrolysate was heated to 90-100°C to inactivate the enzyme and decocted for 0.5-1 hour, and filtered to obtain a mulberry bark water extract.

[0008] Preferably, the aqueous solution of the mulberry leaf water extract in step S4 needs to be pretreated: The mulberry leaf water extract aqueous solution is heated to 80-85°C at a rate of ≥5°C / min, kept warm for 15-30 minutes, and then rapidly cooled to below 40°C.

[0009] Preferably, between step S3 and step S4, a raw material homogenization treatment is further included: the mixture sprayed with the mulberry bark water extract is processed by a twin-screw extruder at 40-60° C. and a rotation speed of 30-50 r / min for 5-10 minutes.

[0010] Preferably, the vacuum sealing in step S6 is packaged using a three-layer composite film, wherein the inner layer is a polyethylene film containing tea polyphenol antibacterial agent, the middle layer is an aluminum foil oxygen barrier layer, and the outer layer is a nylon reinforcement layer.

[0011] Preferably, a protective agent is added during step S6, wherein the protective agent is at least one selected from trehalose, glycerol, sorbitol, and dextran, and the added amount is 0.5-5% of the total mass of the fermentation material.

[0012] Preferably, in step S6, a high-efficiency solid-state fermentation technology is used, including controlling the fermentation temperature within a constant temperature range of 26-28°C, and starting intermittent hypoxic ventilation on the 3rd to 15th day of fermentation, with a ventilation volume of 0.1-0.2 L / kg·min, twice a day, and each ventilation lasting 5-10 minutes.

[0013] Preferably, after step S6 is completed, the following steps are further included: S7. After the fermentation process is completed, the fermented product is crushed and passed through a 40-60 mesh sieve; S8, adding 0.1-0.3% by weight of sodium diacetate to the pulverized fermentation product, and then uniformly mixing; S9, drying the mixed product in an environment of 60-70°C; S10, packaging the dried product to obtain a finished biological feed.

[0014] The present invention has at least the following beneficial effects: The present invention significantly improves the tannin degradation efficiency by leveraging the synergistic effect of a composite fermentation agent (including tannin-degrading bacteria, potato starch-degrading bacteria, and fiber-degrading bacteria) and mulberry bark water extract. Through the synergistic effect of the composite agent, functional water extract, and optimized process, the problem of decreased degradation efficiency caused by a single bacterial species or the lack of key components is solved.

[0015] During the fermentation process of the present invention, potato starch-decomposing bacteria specifically decompose the starch coating structure, thereby significantly improving the starch decomposition rate; the addition of fiber-decomposing bacteria and sugarcane bagasse significantly improves the degradation rate of crude fiber, and the use of composite bacterial agents and protective agents effectively reduces the loss caused by the combination of tannins and proteins, and significantly improves the crude protein retention rate.

[0016] The mulberry leaf aqueous extract of the present invention plays a significant role in ensuring fermentation hygiene and safety. In Comparative Example 8, which lacked the mulberry leaf aqueous extract, the total mold count increased 126-fold, and aflatoxin B1 levels exceeded the standard by 10 times. The synergistic effect of the three bacteria significantly inhibited the growth of other bacteria, reducing mold contamination and aflatoxin B1 levels. The method of the present invention fully utilizes tuber byproducts (such as sweet potato vines) and mulberry resources (such as mulberry branches and leaves), achieving efficient conversion of agricultural waste.

[0017] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below with reference to the embodiments so that those skilled in the art can implement the invention with reference to the description.

[0019] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0020] The tannin-degrading bacteria used in the present invention are all Aspergillus niger (CICC 2487), which were purchased from the China Industrial Microbiological Culture Collection Center; the potato starch-degrading bacteria used are all Bacillus subtilis (CICC 20034), which were purchased from Shandong Sukehan Bioengineering Co., Ltd.; and the fiber-degrading bacteria used are all Trichoderma reesei (CICC13052), which were purchased from the Shanghai Collection Biotechnology Center.

[0021] <Example 1> The bio-feed fermentation method based on tuber by-products and mulberry resources comprises the following steps: Preparation of the mulberry bark aqueous extract: Grind the dried mulberry bark into 20 mesh size, mix with water at a mass ratio of 1:10, add 0.5% of the dry weight of the mulberry bark compound enzyme preparation (cellulase:pectinase:β-glucosidase = 3:2:1, enzyme activity ratio), and hydrolyze at 45°C and pH 4.5 for 1 hour to obtain an enzymatic hydrolyzate. Heat the enzymatic hydrolyzate to 90°C to inactivate the enzymes, boil for 0.5 hour, and filter to obtain the mulberry bark aqueous extract. S1. Weigh mulberry branches and leaves, sweet potatoes, and sweet potato vines in a ratio of 0.5:0.5:0 based on fresh weight. S2, add 3% of the total fresh weight of bagasse to the above raw materials and mix well; S3, spraying mulberry bark water extract (concentration 2g / L), spraying amount is 10mL / kg raw material; The mixture was homogenized by a twin-screw extruder at 40 °C and a rotation speed of 30 r / min for 5 min; S4. Add 3 g / L of mulberry leaf water extract (pretreatment: heating to 80°C at a rate of 5°C / min, keeping warm for 15 minutes, and rapidly cooling to below 40°C), and mix well; S5. Add 0.5% of the total fresh weight of the raw materials into a composite fermentation agent (ratio of viable bacteria: tannin-degrading bacteria: potato starch-degrading bacteria: fiber-degrading bacteria = 1.5:0.8:0.8); S6. Add 0.5% trehalose by weight to the material, package it with a three-layer composite film (inner layer of polyethylene film containing tea polyphenol antimicrobial agent, middle layer of aluminum foil oxygen barrier layer, outer layer of nylon reinforcement layer), vacuum seal it, control the fermentation temperature to 26°C, and start intermittent hypoxic ventilation (ventilation rate 0.1 L / kg·min, twice a day, each time for 5 minutes) from the 3rd to the 15th day of fermentation. The total fermentation time is 30 days. S7: After the fermentation is completed, the product is crushed and passed through a 40-mesh sieve; S8: Add 0.1% sodium diacetate to the crushed product and mix well; S9: Drying at 60℃; S10: Packaging, and the finished product is obtained.

[0022] <Example 2> The bio-feed fermentation method based on tuber by-products and mulberry resources comprises the following steps: Preparation of the mulberry bark aqueous extract: Dried mulberry bark was ground into 30 mesh, mixed with water at a mass ratio of 1:12.5, and a composite enzyme preparation (cellulase:pectinase:β-glucosidase = 4:3:1, enzyme activity ratio) was added at 1.0% of the dry weight of the mulberry bark. Enzymatic hydrolysis was performed at 50°C and pH 5.0 for 1.5 hours to obtain an enzymatic hydrolyzate. The enzymatic hydrolyzate was heated to 95°C to inactivate the enzymes and decocted for 0.75 hours. The resulting solution was filtered to obtain the mulberry bark aqueous extract. S1. Weigh mulberry branches and leaves, sweet potatoes, and sweet potato vines in a ratio of 1.25:1.25:1 based on fresh weight. S2. Add 4% of the total fresh weight of bagasse to the above raw materials and mix well; S3, spraying mulberry bark water extract (concentration 2.5g / L), spraying amount is 12.5mL / kg raw material; The mixture was homogenized by a twin-screw extruder at 50 °C and a rotation speed of 40 r / min for 7.5 min; S4, adding 4 g / L of mulberry leaf water extract aqueous solution (pretreatment: heating to 82.5°C at a rate of 6°C / min, keeping warm for 22.5 minutes, and rapidly cooling to below 40°C), and mixing well; S5. Add 0.75% of the total fresh weight of the raw materials into a composite fermentation agent (ratio of viable bacteria: tannin-degrading bacteria: potato starch-degrading bacteria: fiber-degrading bacteria = 2:1:1); S6. Add 2.75% glycerol to the material, package it in a three-layer composite film (inner layer of polyethylene film containing tea polyphenol antimicrobial agent, middle layer of aluminum foil oxygen barrier layer, outer layer of nylon reinforcement layer), vacuum seal it, control the fermentation temperature to 27°C, and start intermittent hypoxic ventilation (ventilation rate 0.15 L / kg·min, twice a day, each time for 7.5 minutes) from the 3rd to the 15th day of fermentation. The total fermentation time is 35 days. S7: After the fermentation is completed, the product is crushed and passed through a 50-mesh sieve; S8: Add 0.2% sodium diacetate to the crushed product and mix well; S9: Dry at 65°C; S10: Packaging, and the finished product is obtained.

[0023] <Example 3> The bio-feed fermentation method based on tuber by-products and mulberry resources comprises the following steps: Preparation of mulberry bark aqueous extract: Grind dried mulberry bark into 40 mesh size, mix with water at a mass ratio of 1:15, add 1.5% of the dry weight of the mulberry bark compound enzyme preparation (cellulase:pectinase:β-glucosidase = 5:4:1, enzyme activity ratio), and perform enzymatic hydrolysis at 55°C and pH 5.5 for 2 hours to obtain an enzymatic hydrolyzate. Heat the enzymatic hydrolyzate to 100°C to inactivate the enzymes, boil for 1 hour, and filter to obtain the mulberry bark aqueous extract. S1. Weigh mulberry branches and leaves, sweet potatoes, and sweet potato vines in a ratio of 2:2:2 based on fresh weight. S2, adding 5% of the total fresh weight of bagasse to the above raw materials and mixing evenly; S3, spraying mulberry bark water extract (concentration 3g / L), spraying amount is 15mL / kg raw material; The mixture was homogenized by a twin-screw extruder at 60 °C and a speed of 50 r / min for 10 min; S4. Add 5 g / L of mulberry leaf water extract (pretreatment: heating to 85°C at a rate of 7°C / min, keeping warm for 30 minutes, and rapidly cooling to below 40°C), and mix well; S5. Add 1.0% of the total fresh weight of the raw materials into a composite fermentation agent (ratio of viable bacteria: tannin-degrading bacteria: potato starch-degrading bacteria: fiber-degrading bacteria = 2.5:1.2:1.2); S6. Add 5% sorbitol by weight to the material, package it in a three-layer composite film (inner layer of polyethylene film containing tea polyphenols antimicrobial agent, middle layer of aluminum foil oxygen barrier layer, outer layer of nylon reinforcement layer), vacuum seal it, control the fermentation temperature to 28°C, and start intermittent hypoxic ventilation (ventilation rate 0.2 L / kg·min, twice a day, each time for 10 minutes) from the 3rd to the 15th day of fermentation. The total fermentation period is 40 days. S7: After the fermentation is completed, the product is crushed and passed through a 60-mesh sieve; S8: Add 0.3% sodium diacetate to the crushed product and mix well; S9: Dry at 70℃; S10: Packaging, and the finished product is obtained.

[0024] <blank group> The bio-feed fermentation method based on tuber by-products and mulberry resources comprises the following steps: S1. Weigh mulberry branches and leaves, sweet potatoes, and sweet potato vines in a ratio of 1.25:1.25:1 based on fresh weight. S2. Add 4% of the total fresh weight of bagasse to the above raw materials and mix well; The mixture was homogenized by a twin-screw extruder at 50 °C and a rotation speed of 40 r / min for 7.5 min; S3. Add 2.75% glycerol to the material, package it in a three-layer composite film (inner layer of polyethylene film containing tea polyphenol antimicrobial agent, middle layer of aluminum foil oxygen barrier layer, outer layer of nylon reinforcement layer), vacuum seal it, control the fermentation temperature to 27°C, and start intermittent hypoxic ventilation (ventilation rate 0.15 L / kg・min, twice a day, each time for 7.5 minutes) from the 3rd to the 15th day of fermentation. The total fermentation time is 35 days. S4: After the fermentation is completed, the product is crushed and passed through a 50-mesh sieve; S5: Add 0.2% sodium diacetate to the crushed product and mix well; S6: Drying at 65℃; S7: Packaging, and the finished product is obtained.

[0025] <Performance Test 1> The biological feed prepared in Examples 1 to 3 and the blank group was tested for tannin degradation rate, starch decomposition rate, crude fiber degradation rate, crude protein retention rate, total mold count, and aflatoxin B1, wherein: Tannin degradation rate testing standard: GB / T27985-2011 "Determination of Tannins in Feed - Phosphomolybdic Tungstic Acid Spectrophotometric Method". After the sample is extracted with methanol, a color reaction occurs with the phosphomolybdic tungstic acid reagent. The absorbance is measured at a wavelength of 760nm. The tannin content is calculated by comparing with the standard curve. Tannin degradation rate = (initial tannin amount - end point tannin amount) / initial tannin amount × 100%; The test standard for starch decomposition rate: GB5009.9-2016 "Determination of starch in food - Enzymatic hydrolysis method". The sample is hydrolyzed into glucose by amylase, and the reducing sugar content is determined by 3,5-dinitrosalicylic acid method (DNS), which is then converted into starch decomposition rate. Crude fiber degradation rate test standard: GB / T6434-2006 "Determination of crude fiber in feed - Acid-base washing method", the sample is sequentially treated with dilute acid and dilute alkali boiling, filtered and washed, the residue is dried and weighed, and the degradation rate is calculated; Crude protein retention rate testing standard: GB / T6432-2018 "Determination of crude protein in feeds - Kjeldahl method". The sample is digested with concentrated sulfuric acid to convert nitrogen into ammonium sulfate. After alkaline distillation, the released ammonia is titrated to calculate the crude protein content. Crude protein retention rate = (crude protein amount after fermentation / crude protein amount before fermentation) × 100%; The detection standard for total mold count is GB4789.15-2016 "National Food Safety Standard - Microbiological Examination of Food - Count of Molds and Yeasts". The sample suspension is inoculated into Bengal rose medium and cultured at 28°C for 5 days. The typical colonies are counted. Aflatoxin B1 testing standard: GB5009.22-2016 "National Food Safety Standard - Determination of Aflatoxins Group B and G in Foods". Samples are extracted with methanol and water, cleaned up on an immunoaffinity column, and quantitatively analyzed using a high-performance liquid chromatography (HPLC) fluorescence detector (excitation wavelength 365 nm, emission wavelength 435 nm). The test results are shown in Table 1 below: Table 1 Test results of biological feed performance of Examples 1 to 3 and blank group According to the data in Table 1, among Examples 1 to 3, the tannin degradation rate, starch decomposition rate, crude fiber degradation rate, and crude protein retention rate of Example 2 were all higher than those of Examples 1 and 3, while the total mold count and aflatoxin B1 were significantly lower than those of Examples 1 and 3. This indicates that the parameter combination of Example 2 (raw material ratio of 1.25:1.25:1, composite microbial agent ratio of 2:1:1, and the use of intermediate concentrations of aqueous extract and protective agent) performed best in terms of anti-nutritional factor degradation, nutrient retention, and safety. According to the data in Table 1, the tannin degradation rates of Examples 1 to 3 were significantly better than those of the blank group, indicating that the synergistic effect of the composite fermentation agent and the mulberry bark water extract can effectively destroy the tannin structure. The starch decomposition rates of Examples 1 to 3 were significantly higher than those of the blank group, confirming that potato starch-decomposing bacteria can specifically decompose the starch encapsulation structure. The crude fiber degradation rates of Examples 1 to 3 were significantly better than those of the blank group, demonstrating that the addition of fiber-decomposing bacteria and sugarcane bagasse can significantly improve the degradability of fiber. The crude protein retention rates of Examples 1 to 3 were significantly higher than those of the blank group, indicating that the loss caused by the binding of tannins to proteins was reduced, and that the protective agent inhibited excessive protein degradation. All Examples significantly outperformed the blank group that did not adopt the core technology of the present invention through the composite bacterial agent, functional water extract, and optimized process, verifying the effectiveness of the method of the present invention.

[0026] Comparative Example 1 The biofeed fermentation method based on potato by-products and mulberry resources uses only tannin-degrading bacteria in step S5, and the rest of the preparation method is completely consistent with Example 2; Comparative Example 2 In the biological feed fermentation method based on tuber by-products and mulberry resources, only tuber starch-decomposing bacteria are used in step S5, and the rest of the preparation method is completely consistent with Example 2.

[0027] Comparative Example 3 In the biological feed fermentation method based on potato by-products and mulberry resources, only fiber-decomposing bacteria are used in step S5, and the rest of the preparation method is completely consistent with Example 2.

[0028] Comparative Example 4 In the biofeed fermentation method based on potato by-products and mulberry resources, two bacterial agents, tannin-degrading bacteria and fiber-degrading bacteria, were used in step S5 (live bacteria ratio, tannin-degrading bacteria: fiber-degrading bacteria = 1:1). The rest of the preparation method was exactly the same as in Example 2.

[0029] Comparative Example 5 In the biofeed fermentation method based on potato by-products and mulberry resources, two bacterial agents, tannin-degrading bacteria and potato starch-degrading bacteria, were used in step S5 (viable cell count ratio, tannin-degrading bacteria: potato starch-degrading bacteria = 1:1). The rest of the preparation method was completely consistent with Example 2.

[0030] Comparative Example 6 In the biofeed fermentation method based on potato by-products and mulberry resources, two bacterial agents, fiber-decomposing bacteria and potato starch-decomposing bacteria, are used in step S5 (live bacteria ratio, fiber-decomposing bacteria: potato starch-decomposing bacteria = 1:1). The rest of the preparation method is exactly the same as in Example 2.

[0031] Comparative Example 7 In the bio-feed fermentation method based on tuber by-products and mulberry resources, the mulberry bark water extract in step S3 is not sprayed, but the same amount of pure water is sprayed. The rest of the preparation method is exactly the same as that in Example 2.

[0032] Comparative Example 8 In the biological feed fermentation method based on tuber by-products and mulberry resources, the mulberry leaf water extract aqueous solution in step S4 is not added, but the same amount of pure water is added. The rest of the preparation method is completely consistent with Example 2.

[0033] <Performance Test 2> The biological feeds prepared in Comparative Examples 1 to 8 were tested for tannin degradation rate, starch decomposition rate, crude fiber degradation rate, crude protein retention rate, total mold count, and aflatoxin B1 according to the method in <Performance Test 1>, and compared with the data of Example 2 and the blank group. The results are shown in Table 2 below: Table 2 Biological feed performance test results of comparative examples 1 to 8, embodiment 2 and blank group According to the data in Table 2, when single-strain comparative examples 1 to 3 were used, the tannin degradation rate was significantly lower than that of Example 2 using the three-strain synergistic method. Although there was some improvement in comparative examples 4 to 6 using the dual-strain combination, for example, the tannin degradation rate of comparative example 5 reached 81.2%, it still did not reach the optimal level. This indicates that tannin-degrading bacteria need to work synergistically with starch / fiber-degrading bacteria to completely eliminate the inhibitory effect of tannins. Among them, comparative example 2, which only used starch-degrading bacteria, had a starch decomposition rate close to that of Example 2, but the tannin degradation rate and crude fiber degradation rate were seriously insufficient, which means that undegraded tannins will hinder fiber decomposition. In comparative example 3, which only used fiber-degrading bacteria, although the crude fiber degradation rate was high, the starch decomposition rate was significantly reduced, indicating that the fiber wrapping structure would hinder the release of starch. Moreover, the total mold count and aflatoxin B1 in the single or dual-strain groups were much higher than those in Example 2, which confirmed that the synergistic effect of the three bacteria can effectively inhibit the growth of miscellaneous bacteria.

[0034] Comparative Example 7, which lacked the mulberry bark aqueous extract, showed significantly lower tannin degradation rates and crude fiber degradation rates compared to Example 2. Combined with the tannin degradation rates of the blank group, this indicates that the mulberry bark aqueous extract is a key inducer of tannin-degrading bacteria. Furthermore, fungal contamination in Comparative Example 7 was significantly increased compared to Example 2, demonstrating that the mulberry bark aqueous extract also inhibits the proliferation of other bacteria.

[0035] Compared with Example 2, the tannin degradation rate and starch decomposition rate of Comparative Example 8 were less affected, but the total mold count increased by 126 times and aflatoxin B1 exceeded the standard by 10 times, which highlights the irreplaceable role of mulberry leaf water extract in controlling fermentation hygiene and safety.

[0036] This invention leverages the synergistic effect of a composite bacterial agent (tannin-degrading bacteria: starch-degrading bacteria: fiber-degrading bacteria = 1.5-2.5:0.8-1.2:0.8-1.2) and mulberry bark / leaf extract to achieve efficient tannin degradation and sufficient release of nutrients, while significantly suppressing contamination by other bacteria. Therefore, the absence of any key component (such as a single bacterial species or mulberry extract) would lead to decreased degradation efficiency or increased sanitary risks, demonstrating the holistic and innovative nature of this technical solution.

[0037] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A bio-feed fermentation method based on potato by-products and mulberry resources, characterized in that: The following steps are involved: S1. Weigh mulberry branches and leaves, sweet potatoes, and sweet potato vines according to their fresh weight ratio, with a mixing ratio of mulberry branches and leaves: sweet potatoes: sweet potato vines = 0.5~2:0.5~2:0~2; S2. Adding bagasse to the raw material of step S1 in an amount of 3-5% of the total fresh weight of the raw material; S3, spraying 2-3 g / L of mulberry bark water extract at a spraying rate of 10-15 mL / kg of raw material; S4, add 3-5 g / L of mulberry leaf water extract aqueous solution and mix well; S5. Add 0.5-1.0% of the total fresh weight of the raw materials as a composite fermentation agent, wherein the composite fermentation agent includes tannin-degrading bacteria, potato starch-degrading bacteria, and fiber-degrading bacteria at a ratio of viable bacteria of 1.5-2.5:0.8-1.2:0.8-1.2; S6. Vacuum seal and ferment at 25-30℃ for 30-40 days.

2. The bio-feed fermentation method based on potato by-products and mulberry resources according to claim 1, characterized in that: The preparation of the mulberry bark water extract comprises the following steps: Grind the dried mulberry bark into 20-40 mesh, and mix the ground mulberry bark with water at a mass ratio of 1:10-15; Adding 0.5-1.5% of the dry weight of mulberry bark complex enzyme preparation, the complex enzyme preparation is composed of cellulase, pectinase and β-glucosidase in an enzyme activity ratio of 3-5:2-4:1; Enzyme hydrolysis at 45-55°C and pH 4.5-5.5 for 1-2 hours to obtain an enzymatic hydrolyzate; The enzymatic hydrolysate was heated to 90-100°C to inactivate the enzyme and decocted for 0.5-1 hour, and filtered to obtain a mulberry bark water extract.

3. The bio-feed fermentation method based on potato by-products and mulberry resources according to claim 1, characterized in that: In step S4, the aqueous solution of mulberry leaf water extract needs to be pretreated: The mulberry leaf water extract aqueous solution is heated to 80-85°C at a rate of ≥5°C / min, kept warm for 15-30 minutes, and then rapidly cooled to below 40°C.

4. The bio-feed fermentation method based on potato by-products and mulberry resources according to claim 3, characterized in that: Between step S3 and step S4, a raw material homogenization process is also included: the mixture sprayed with the mulberry bark water extract is processed by a twin-screw extruder at 40-60° C. and a rotation speed of 30-50 r / min for 5-10 minutes.

5. The bio-feed fermentation method based on potato by-products and mulberry resources according to claim 1, characterized in that: The vacuum sealing in step S6 is packaged using a three-layer composite film, with an inner layer being a polyethylene film containing tea polyphenol antibacterial agent, a middle layer being an aluminum foil oxygen barrier layer, and an outer layer being a nylon reinforcement layer.

6. The bio-feed fermentation method based on potato by-products and mulberry resources according to claim 1, characterized in that: In step S6, a protective agent is added, wherein the protective agent is at least one selected from trehalose, glycerol, sorbitol, and dextran, and the added amount is 0.5-5% of the total mass of the fermentation material.

7. The bio-feed fermentation method based on potato by-products and mulberry resources according to claim 6, characterized in that: In step S6, a high-efficiency solid-state fermentation technology is used, including controlling the fermentation temperature within a constant temperature range of 26-28°C, and initiating intermittent hypoxic ventilation on the 3rd to 15th day of fermentation, with a ventilation volume of 0.1-0.2 L / kg·min, twice a day, and each ventilation lasting 5-10 minutes.

8. The biological feed fermentation method of potato by-products and mulberry resources as claimed in claim 1, characterized in that After step S6 is completed, the following steps are further included: S7. After the fermentation process is completed, the fermented product is crushed and passed through a 40-60 mesh sieve; S8, adding 0.1-0.3% by weight of sodium diacetate to the pulverized fermentation product, and then uniformly mixing; S9, drying the mixed product in an environment of 60-70°C; S10, packaging the dried product to obtain a finished biological feed.

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