Feed plant enzymolysis protein with strong food calling effect and preparation method of feed plant enzymolysis protein

Abstract

The invention relates to the field of feed raw materials, and discloses a feed plant enzymolysis protein with a strong food calling effect and a preparation method thereof, the preparation method comprises the following steps: S1, dispersing and reducing viscosity: reducing the viscosity of a protein powder raw material through shearing force generated by high-speed rotation of a dispersing disc; step S2, enzymolysis of polysaccharide substances: plant protein powder is added into a reaction kettle in which water is added in advance, then polysaccharide enzymes are added, and enzymolysis is performed; step S3: proteolysis: adding sodium carbonate to adjust pH, adding compound protease into the reaction kettle, and performing enzymolysis; and S4, conveying the wet material to a spray drying tower for spray drying. According to the method, the pea powder syrup protein powder, the wheat protein powder and the soybean concentrated protein powder are used as raw materials, through dispersion, enzymolysis and spray drying, flavor substances are generated, the bitter taste is eliminated, the palatability of plant protein is remarkably improved, the strong food calling performance is shown in feeding experiments of piglets and cats, and the method is few in steps, mild in reaction condition and low in cost.

Description

Technical Field

[0001] The invention relates to the field of feed raw materials, and in particular to a feed plant enzymatic protein with a strong feeding effect and a preparation method thereof. Background Art

[0002] Studies have shown that animals such as pigs, cats, and dogs prefer umami, sweetness, and certain Maillard flavors, and reject bitterness and astringency (McLaughlin, 1983; Moser et al, 1986). In the formulation of livestock and poultry or pet feed, it is usually necessary to add protein raw materials with appetizing properties to increase the animal's feed intake. Formulators usually choose to use animal-derived protein raw materials such as plasma protein powder, fish meal, and chicken liver powder, or use yeast hydrolyzates from microorganisms. The main characteristics of these protein raw materials are strong appetizing properties, obvious umami flavor, and no antigens. Therefore, pigs, cats, dogs, and other animals prefer such protein raw materials to plant proteins. Among them, cats are obligate carnivores. The appetizing proteins in current cat food are completely derived from animals or microorganisms. Plant protein raw materials have almost no sweetness, and some plant proteins even have unpleasant flavors such as bitterness and astringency. Therefore, it is generally believed that plant proteins do not have an appetizing effect. In addition, many plant proteins such as soy protein and wheat protein also contain anti-nutritional factors such as antigens, which affect the intestinal health of animals and further reduce the utilization rate of plant proteins. Compared with plant protein, the supply of animal protein is much lower and its price is much higher than that of plant protein. Therefore, how to replace part of animal protein with plant protein is a key issue that urgently needs to be broken through in the current pet market.

[0003] At present, various methods such as maturation, fermentation, and enzymolysis can improve the bad flavor of plant proteins and reduce antigens to a certain extent, but they cannot significantly improve the appetizing properties. Studies have shown that the use of specific enzyme combinations and controlled hydrolysis of certain animal proteins and microbial proteins can produce obvious flavors (Qiu Yanxiang et al., 2017; Knorr et al., 1979). However, there is currently no research on how to make plant proteins highly appetizing through enzymolysis, and there are no highly appetizing plant protein products on the market.

[0004] Plant protein comes from a variety of sources, including soybeans, wheat, peanuts, peas, etc. Different plant protein raw materials have significantly different flavor characteristics, protein structure characteristics and production processes of the plants themselves. These factors will affect the taste and flavor of the final product. Therefore, it is particularly important to choose the right raw materials and ratios for enzymatic hydrolysis.

[0005] Due to the underdevelopment and cost constraints of existing enzymatic hydrolysis technology, as well as different proteases with different enzymatic sites and optimal conditions, there is not much inspiration for the existing enzymatic hydrolysis technology to increase the appetizing flavor of plant proteins, so it is necessary to control the conditions from multiple aspects for testing. Single enzymatic hydrolysis is relatively simple, low-cost, and suitable for specific application needs; while compound enzymatic hydrolysis may be more complicated in operation and require more experimental optimization and technical support, it can provide more diverse peptides and possible synergistic effects, and has a greater possibility of increasing the fresh and sweet flavor of plant proteins, thereby enhancing appetizing properties.

[0006] The Maillard reaction plays an important role in the processing of animal enzymatic proteins such as enzymatic chicken liver powder. By controlling the conditions of the Maillard reaction, the flavor and appetitivity of the good flavor of the animal enzymatic protein itself can be further enhanced. However, due to the lack of flavor of plant protein itself, the Maillard reaction is rarely used in the flavor development of plant enzymatic proteins.

[0007] To sum up, the market has a strong demand for plant protein with strong appetizing effects. Summary of the invention

[0008] The purpose of the present invention is to provide a plant enzymatic protein for feeding with strong feeding effect and a preparation method thereof, in view of the current situation that the cost of animal protein or microbial protein for feeding is high, while plant protein for feeding is cheap but has insufficient flavor, poor feeding effect and may contain anti-nutritional factors. The crude protein of the product of the present invention is ≥50%, the acid-soluble protein is ≥25%, the small peptide of 150-1000Da is ≥15%, the in vitro protein digestibility is ≥90%, there is no anti-nutritional factor, and it shows a strong feeding effect in feeding tests of piglets and cats.

[0009] The technical solution of the present invention is as follows: The present invention provides a method for preparing enzymatic protein of forage plants with strong feeding effect, comprising the following steps: Step S1: Dispersion of raw materials: Add plant protein powder into a reactor to which a certain amount of water has been added in advance; since the selected plant protein raw material has strong viscosity, at least two serrated dispersion disks are installed at different heights in the stirring tank, and the shear force generated by the dispersion disk rotating at a speed of 1400-1600 revolutions per minute is used to reduce the viscosity of the protein powder raw material.

[0010] Step S2: Enzymatic hydrolysis of polysaccharide substances: Then, a certain amount of polysaccharide enzymes are added and reacted at 50-55°C for 3-4 hours to obtain sugars with strong sweetness required for the Maillard reaction and some prebiotics; Step S3: Enzymatic hydrolysis of protein: sodium carbonate is added to adjust the pH to 7.0-8.0, and composite protease is added to the reactor, and the reaction is carried out at 50-55°C for 5-7 hours to improve the digestibility, obtain flavor peptides and eliminate bitterness; Step S4: performing Maillard reaction while spray drying, thereby obtaining enzymatic protein powder of fodder plant with a strong feeding effect.

[0011] On the basis of screening out suitable plant protein raw materials and proportions, through the comprehensive effect of coordination between the steps of the above-mentioned preparation method, parameter setting and selection of enzymes, a feed plant protein with a strong appetite-attracting effect was successfully prepared by enzymatic hydrolysis. The plant protein is light yellow in color and has a good appearance; it has a distinct sweet and fresh flavor and Maillard flavor, which promotes the appetite of animals and increases their intake; at the same time, the feed also has a good digestibility, can promote animals to digest and absorb nutrients, eliminate anti-nutritional factors, and has a good effect of protecting the gastrointestinal tract of suckling pigs and avoiding diarrhea, which can be said to kill four birds with one stone.

[0012] According to a preferred embodiment, the raw material used for the plant protein is a mixture of pea slurry protein powder, wheat protein powder and soy protein concentrate powder, and the added weight percentages are 60-65%, 20-25% and 10-15% respectively.

[0013] According to a preferred embodiment, the polysaccharidase in step S2 is one or more of amylase, pullulanase, xylanase, neutral mannanase, cellulase or pectinase.

[0014] According to a preferred embodiment, the amount of polysaccharidase added in step S2 is 20000-40000 U per kilogram of raw material.

[0015] According to a preferred embodiment, the amount of water added in step S1 is 1.8-2.2 times the weight of the plant protein powder raw material.

[0016] According to a preferred embodiment, the composite protease in step S3 is at least two of neutral protease, aminopeptidase, carboxypeptidase, endopeptidase composite or cysteine ​​protease.

[0017] According to a preferred embodiment, the amount of the composite protease added in step S3 is 350,000-400,000 U per kilogram of raw material.

[0018] According to a preferred embodiment, step S4 is specifically as follows: the wet material is transported to a spray drying tower for spray drying. Wheat protein powder, concentrated soy protein powder, and pea slurry protein powder have higher viscosity than general plant protein raw materials, and are more sensitive to temperature. Too high temperature or too long heating time will cause the color to deepen significantly and the bitterness to increase. Therefore, the products of these proteins after liquid enzymatic hydrolysis have higher requirements for the drying process, and it is necessary to solve the wall adhesion problem caused by high viscosity and shorten the drying time. Spray drying is an effective method to solve the above problems.

[0019] According to a preferred embodiment, in step S4, the spray drying is performed using a pressure-type spray drying tower.

[0020] According to a preferred embodiment, in step S4, the spray drying air inlet temperature is 180-220°C and the air outlet temperature is 70-90°C.

[0021] According to a preferred embodiment, in step S4, the particle size range of the spray-dried product is required to be all above 80 mesh.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. Existing comparative document 1 (CN104745650A) discloses a method for preparing bound glutamine for improving intestinal nutrition of piglets. The comparative document also adopts the enzymatic hydrolysis process of amylase and protease, but the process objectives and details are essentially different: the purpose of adding amylase in the comparative document is only to reduce the starch content and prevent starch from hindering subsequent protease hydrolysis. Therefore, there is no clear goal for the type and content of starch hydrolysis products, and the direction and product of starch hydrolysis are not controlled. The specific type of amylase and reaction conditions used in the present invention are clearly for obtaining sweet sugar substances with strong appetitiveness and controlling the content of its components to suit the taste preferences of animals; the process purpose of adding protease in the comparative document is to obtain glutamine to the greatest extent, not to obtain the best flavor substances; therefore, the function of the product obtained by the process used in the comparative document is mainly to promote the intestinal development and health of pigs, and does not show appetitiveness or increase feed intake, while the product of the present invention not only promotes the intestinal health of piglets and reduces diarrhea, but also shows a strong appetitive effect, significantly increasing the feed intake of piglets and cats.

[0023] 2. Existing comparative document 2 (CN110628747A) discloses a combined amylase and its application. The amylase invented by the inventor is added to the feed to increase the feed intake of piglets, but the application method, principle and effect are essentially different from the present invention. The application method is to add amylase as an additive to the feed, and the animal will function in its intestine after eating, while the amylase used in the present invention is directly used for processing and enzymatic hydrolysis of protein feed, and has no activity in the animal intestine, so the application scenarios are different; the principle of increasing the animal's feed intake in the comparative document is that amylase regulates the starch digestion rate in the animal intestine, and then controls the blood sugar concentration of the animal after eating, prevents excessive blood sugar concentration from reducing appetite, prolongs the animal's feeding desire, and thus increases the feed intake. Therefore, the amylase invented by the inventor does not make the feed itself have a competitive advantage in terms of appetitiveness, while the product of the present invention is the flavor substances produced by amylase, protease enzymatic hydrolysis and Maillard reaction to increase the appetitiveness of the feed itself, thereby increasing the feed intake and making the feed more competitive in terms of appetitiveness.

[0024] 3. Existing comparative document 3 (CN102548427B) discloses a method for enhancing the palatability of animal digesta. Comparative document 3 also uses the process of protease hydrolysis and Maillard reaction to achieve the goal of improving protein raw materials and thus enhancing the palatability of protein, but the raw materials targeted are different from those of the present invention. The raw materials targeted are animal visceral proteins, which have strong appetizing properties and no bad taste or anti-nutritional factors, so the improvement is easy. The raw materials targeted by the present invention are plant proteins with bad flavors and difficult to improve. Compared with the technology provided by the comparative document, the technology of the present invention is more valuable for improving the flavor of plant protein raw materials. The product of the present invention also provides room for reducing costs for the protein feed market and breeding enterprises, and can be used to replace animal and microbial proteins.

[0025] 4. It is almost a consensus in the feed industry that plant protein tastes bad and its appetizing property is much lower than that of animal protein and microbial protein. However, the enzymatic protein produced by the present invention has an appetizing property far superior to that of ordinary plant protein in feeding tests of piglets and cats. Its appetizing effect significantly exceeds that of the control group, i.e., the commonly used animal protein and microbial protein formula. In addition, it has a high digestibility, contains prebiotics and is free of antigens, so that piglets show faster growth and less diarrhea after eating. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a diagram of the experimental results of animal verification (pet cat) of Example 1 of the present invention. DETAILED DESCRIPTION

[0027] It should be noted that the test methods in the following examples are conventional methods unless otherwise specified. The test materials used in the following examples are all commercially available. The sodium carbonate, amylases, and composite proteases used are selected from commercially available products of multiple enzyme preparation companies.

[0028] The processing equipment used in the present invention includes a reaction kettle, a conveying equipment, a spray drying tower, etc., all of which are independently designed by the company.

[0029] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0030] Example 1 A method for preparing a feed plant protein with a fresh and sweet flavor, comprising the following steps: S1: weigh a total of 300 kg of wheat protein powder (195 kg), soy concentrated egg powder (75 kg), and pea slurry protein powder (30 kg) into a reactor, add 540 liters of water, and use a sawtooth dispersion disk to disperse at a speed of 1400 revolutions per minute for 30 minutes; S2: Add 6 million U polysaccharidase (α-amylase: pullulanase: NSP complex enzyme = 2:1:1) and react at 55°C for 4 hours; S3: Add 4.95 kg of sodium carbonate to adjust the pH to 7.5, add 105 million U of composite protease (neutral protease: aminopeptidase: endopeptidase = 2:1:1), and react at 55°C for 5 hours.

[0031] S4: The wet material is transported to a spray drying tower for spray drying, with an inlet air temperature of 200°C and an outlet air temperature of 85°C.

[0032] Analysis and evaluation: (1) Sample testing (3 samples): color, taste, smell (sensory evaluation by 10 trained evaluators, the majority evaluation result shall prevail); crude protein, acid-soluble protein, and small peptide content of 150-1000 Da. The results are shown in Table 1: Table 1 Sample test results

[0033] (2) Animal verification (piglets) 400 suckling piglets (average age 26 days) were selected and transferred to the same nursery house. They were weighed according to their weight and paired into two treatment groups according to their weight proximity, with 4 pens in each group. The pen conditions of each group were basically the same according to the ventilation and lighting positions of the pens. Two kinds of feed were fed respectively. Group A was fed with the creep feed of the control group (containing 1.25% yeast hydrolyzate + 2.8% fish meal), and Group B was fed with the creep feed of the test group, with 2.5% of the plant protein prepared in this embodiment added, and other protein raw materials in the original formula (1.25% yeast hydrolyzate + 1% fish meal) were reduced to ensure that the energy and protein of the feed were basically consistent. The production processes of the two feeds were the same. Yeast hydrolyzate and fish meal are the most recognized protein products with the most obvious umami taste in the feed field. Comparing the effects of the plant protein for feeding of the present application with them can highlight the umami taste of the plant protein for feeding of the present application. The information of the two groups is shown in Table 2: Table 2 Animal experiment groups

[0034] The results of feed intake are shown in Table 3. The feed intake in the first four days after weaning is the key to reflect the palatability of feed. Compared with the control group, the feed in the experimental group increased by 17g / d, indicating that the feed in the experimental group in the first four days of weaning is conducive to relieving the weaning stress of piglets and helping them to eat quickly. Compared with the control group, the total feed intake in the first two weeks after weaning was 17.6kg higher in the experimental group, and the average daily feed intake increased by 5g / head / d. This shows that the experimental group has an advantage over the control group in promoting feed intake.

[0035] Table 3 Feed intake results

[0036] The results of diarrhea are shown in Table 4. Compared with the control group, the total number of diarrhea in the experimental group of pigs was reduced by 21 times, and the number of days of diarrhea was shortened by 6 days. Diarrhea reached its peak on the 6th day after weaning, and the total number of diarrhea in the experimental group of pigs was reduced by 18 times, and the number of days of diarrhea was shortened by 4 days. It shows that the addition of the enzymatic plant protein of the present application to the feed of the experimental group alleviated the intestinal damage caused by weaning stress and promoted the intestinal development of piglets and rapid repair of damage.

[0037] Table 4 Diarrhea results

[0038] The weight gain results are shown in Table 5. Compared with the control group, the daily weight gain of the experimental group increased by 11g / head / d within 2 weeks after weaning, and the average weight of the head increased by 200g / head. This shows that the feed of the experimental group is more conducive to promoting the growth of piglets and improving feed conversion rate.

[0039] Table 5 Results of weight gain and feed ratio

[0040] (2) Animal verification (pet cat) A double-bowl test was conducted by a third-party testing agency (Huace Testing) to test the appetitiveness of the product of the present invention to cats. 20 cats were selected and fed for 4 consecutive days to test the feeding rate. The sample information of the experimental group and the control group is shown in Table 6: Table 6 Experimental groups

[0041] The test results are as follows Figure 1 As shown, the feeding rate of the experimental group adding the product of the present invention is significantly higher than that of the control group, indicating that the product of the present invention has a strong appetite-inducing effect on cats. It not only breaks the conventional perception that cats, as obligate carnivores, cannot accept plant protein, but also has a better appetite-inducing effect than animal protein.

[0042] Example 2 A method for preparing a feed plant protein with a fresh and sweet flavor, comprising the following steps: S1: weigh a total of 300 kg of wheat protein powder (180 kg), soy concentrated egg powder (75 kg), and pea slurry protein powder (45 kg) into a reactor, add 600 liters of water, and use a sawtooth dispersion disk to disperse at a speed of 1600 revolutions per minute for 30 minutes; S2: Add 12 million U of polysaccharidase (α-amylase: pullulanase: NSP complex enzyme = 2:1:1) and react at 50°C for 2 hours.

[0043] S3: Add 4.0 kg of sodium carbonate to adjust the pH to 7.0, add 120 million U of composite protease (neutral protease: aminopeptidase: endopeptidase = 2:1:1), and react at 50°C for 7 hours.

[0044] S4: The wet material is transported to a spray drying tower for spray drying, with an inlet air temperature of 210°C and an outlet air temperature of 90°C.

[0045] Analysis and evaluation: (1) Sample testing (3 samples): color, taste, smell (sensory evaluation by 10 trained evaluators, the majority evaluation result shall prevail); crude protein, acid-soluble protein, and small peptide content of 150-1000 Da. The results are shown in Table 7: Table 7 Sample test results

[0046] (2) Animal verification In a pig farm different from Example 1, 110 suckling piglets (average age 29 days) were selected, and they were kept in the original farrowing bed for feeding after weaning. They were divided into two treatment groups according to the weight, age and number of pigs in each litter, with 6 pens in each group. The conditions of each group were basically the same according to the ventilation and lighting positions of the pens. Two kinds of feed were fed respectively, group A was fed with a control feed (containing 1.25% yeast hydrolyzate + 2.8% fish meal), and group B was fed with a test feed with 2.5% of the plant protein prepared in this example added, and other protein raw materials (1.25% yeast hydrolyzate + 1% fish meal) in the original formula were reduced. The information of the two groups is shown in Table 8 below: Table 8 Animal experiment groups

[0047] The results of feed intake are shown in Table 9. Feed intake in the first four days after weaning is the key to reflect the palatability of feed. The experimental group increased by 23g / head / d. Compared with the control group, the total feed intake in the first two weeks after weaning was 33kg higher in the experimental group, and the average daily feed intake increased by 26g / head / d. The experimental group has an advantage over the control group in promoting feed intake.

[0048] Table 9 Feed intake results

[0049] The diarrhea results are shown in Table 10. Compared with the control group, the total number of diarrhea episodes in the experimental feed group was reduced by 13. The diarrhea peaked on the 4th day after weaning (the diarrhea peak period varied from farm to farm), and the total number of diarrhea episodes in the experimental group was reduced by 12. This indicates that the experimental group reduced the intestinal damage caused by weaning stress and promoted the intestinal development and rapid repair of damage in piglets.

[0050] Table 10 Diarrhea results

[0051] The weight gain results are shown in Table 11. Compared with the control group, the experimental feed group gained 18g / head / d more on the second day after weaning, and the average weight gain was 300g / head. This shows that the feed in the experimental group is more conducive to promoting the growth of piglets.

[0052] Table 11 Results of weight gain and feed ratio

[0053] Comparative Example 1 The difference from Example 1 is that three groups of composite proteases of different types from those in Example 1 are used respectively, and the other conditions are the same.

[0054] Sample testing: color, taste, smell; crude protein, acid-soluble protein, 150-1000Da small peptide content. The results are shown in Table 12. The three composite proteases of Comparative Example 1 (single enzymes in each composite enzyme were added in equal amounts) were unable to produce fresh and sweet taste while removing bitterness.

[0055] Table 12 Sample test results

[0056] Comparative Example 2 Comparative Example 2 is different from Example 1 in that polysaccharidase from different sources is used (single enzyme in each complex enzyme is added in equal amounts), and other conditions are the same.

[0057] Sample testing: color, sweetness, smell, the results are shown in Table 13. From Table 13, it can be seen that the polysaccharidase selected in the present application has a better performance in producing sweetness, while polysaccharidase 1 and polysaccharidase 2 cannot produce relevant effects.

[0058] Table 13 Sample test results

[0059] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the action time of the amylase is different, and the other conditions are the same.

[0060] Sample testing: color, sweetness, smell, the results are shown in Table 14. As can be seen from Table 14, when the amylase action time is within 3-4h, the feed has a more abundant sweetness.

[0061] Table 14 Sample test results

[0062] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the whole reaction temperature is different (the reaction temperature of polysaccharidase and complex protease), and the other conditions are the same.

[0063] Sample testing: color, sweetness, smell, acid-soluble protein, the results are shown in Table 15. As can be seen from Table 15, the enzymatic reaction temperature of polysaccharidase and composite protease is 52-55°C, which can ensure that the color, sweetness and umami of the product are better and the content of acid-soluble protein is higher; when the temperature is too high, the umami taste will decrease, the product color will become darker and the content of acid-soluble protein will decrease.

[0064] Table 15 Sample test results

[0065] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the proteolysis time is different, and the other conditions are the same.

[0066] Sample testing: color, umami, acid-soluble protein, the results are shown in Table 16. As shown in Table 16, when the enzymatic hydrolysis time is 5-7h, the umami taste of the product is stronger and the content of acid-soluble protein increases.

[0067] Table 16 Sample test results

[0068] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that the pH conditions of proteinase hydrolysis are different, and the other conditions are the same.

[0069] Sample testing: color, umami, acid-soluble protein, the results are shown in Table 17. As shown in Table 17, within the range of 6.8-8.2, with the increase of the pH of the proteolysis, the acid-soluble protein content and the umami of the product both showed a trend of first increasing and then decreasing; the pH range of 7.0-8.0 was the best.

[0070] Table 17 Sample test results

[0071] Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that the spray drying air inlet temperature is different, and the other conditions are the same.

[0072] Sample testing: color, taste, and smell The results are shown in Table 18. As shown in Table 18, when the inlet air temperature is 170°C, the color of the product is darker; and when the inlet air temperature is 230°C, the color of the product is brown with a bitter taste, because the inlet air temperature of the product is preferably 180-220°C.

[0073] Table 18 Sample test results

Claims

1. A method for preparing enzymatic protein of fodder plants with strong feeding effect, characterized in that: The steps include: Step S1: adding the plant protein powder raw material into a reaction kettle into which water has been added in advance, and stirring while dispersing the plant protein powder raw material through a dispersion disk to reduce the viscosity of the plant protein powder raw material; Step S2: Enzymatic hydrolysis of polysaccharides: adding polysaccharide enzymes and reacting at 50-55°C for 3-4h; Step S3: Enzymatic hydrolysis of protein: sodium carbonate was added to adjust the pH to 7.0-8.0, and composite protease was added to the reaction kettle, and the reaction was carried out at 50-55°C for 5-7h; Step S4: spray drying to obtain the enzymatic protein of the forage plant with a strong feeding effect.

2. The method for preparing a forage plant enzymatic protein with a strong feeding effect according to claim 1, characterized in that: The dispersion by the dispersion disk in step S1 is to disperse the raw materials by high-speed rotation of a sawtooth dispersion disk.

3. The method for preparing a forage plant enzymatic protein with a strong appetite-inducing effect according to claim 1, characterized in that: The plant protein powder raw material is a mixture of pea slurry protein powder, wheat protein powder and soybean concentrated protein powder, with the mass percentages being 60-65%, 20-25% and 10-15%.

4. The method for preparing a forage plant enzymatic protein with a strong appetite-inducing effect according to claim 1, characterized in that: The polysaccharidase in step S2 is one or more of amylase, saccharifying enzyme, pullulanase, xylanase, neutral mannanase, cellulase or pectinase.

5. The method for preparing a forage plant enzymatic protein with a strong feeding effect according to claim 4, characterized in that: In step S2, the amount of polysaccharidase added is 20,000-40,000 U per kilogram of raw material.

6. The method for preparing a forage plant enzymatic protein with a strong feeding effect according to claim 1, characterized in that: The amount of water added in step S1 is 1.8-2.2 times the weight of the plant protein powder raw material.

7. The method for preparing a forage plant enzymatic protein with a strong appetite-inducing effect according to claim 1, characterized in that: The composite protease in step S3 is at least two of neutral protease, aminopeptidase, endopeptidase composite or cysteine ​​protease.

8. The method for preparing a forage plant enzymatic protein with a strong appetite-inducing effect according to claim 7, characterized in that: The amount of compound protease added in step S3 is 350,000-400,000 U per kilogram of raw material.

9. The method for preparing a forage plant enzymatic protein with a strong feeding effect according to claim 1, characterized in that: In step S4, the spray drying air inlet temperature is 200-220°C and the air outlet temperature is 70-90°C.

10. A plant enzymatic protein for feed with strong feeding effect, characterized in that: Includes the following materials in parts by weight: Crude protein ≥50%, acid-soluble protein ≥25%, small peptides 150-1000Da ≥15%, in vitro protein digestibility ≥90%, no anti-nutritional factors.

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