A method for improving the quality of rehydrated corn grain silage dried by using fresh grass press liquor

Abstract

This invention belongs to the field of feed processing, specifically disclosing a method for improving the quality of rehydrated corn kernel silage using fresh grass press liquor. The method involves mixing corn kernels obtained after crushing them with fresh grass press liquor, then filling the mixture into silage bags or silage tanks, sealing them, and then anaerobically storing them for 90-180 days. This method utilizes the attached lactic acid bacteria, soluble sugars, vitamins, and other nutrients contained in the fresh grass press liquor, which can quickly initiate the fermentation of rehydrated corn kernel silage, resulting in rapid fermentation and good fermentation quality. Secondly, it produces less gas during fermentation, minimizing the loss of dry matter in the corn kernels. Furthermore, the pH decreases rapidly and significantly, inhibiting the growth of harmful bacteria and prolonging the aerobic stability of the silage after opening. The acidic aroma produced in this method also improves the palatability of the feed, increasing animal feed intake.

Description

Technical Field

[0001] This invention belongs to the field of feed processing and silage storage, and specifically relates to a method for improving the quality of rehydrated silage of dried corn kernels using fresh grass pressing liquid. Background Technology

[0002] Corn kernels are an important energy feed in the diets of ruminants. Dried corn kernels have the advantages of being easy to transport over long distances and store for extended periods, but their dense, hard endosperm structure presents challenges in palatability and slow nutrient release when used directly as feed. To improve the feed efficiency of corn kernels, a processing method combining crushing, rehydration, and silage is often used in production, allowing for moderate fermentation under anaerobic conditions to enhance their feed value.

[0003] Corn kernel rehydrated silage differs from conventional green silage. Corn kernels have a low moisture content, a limited number of naturally attached lactic acid bacteria, and a slow release rate of soluble sugars, resulting in a delayed fermentation start-up. Furthermore, improper rehydration methods or the selection of additional media can easily lead to insufficient acid production, slow pH reduction, proliferation of yeast and other contaminating microorganisms, increased fermentation losses, and easy spoilage after opening. Current technologies typically use water addition for rehydration or the use of exogenous microbial agents for fermentation regulation. However, simply adding water only improves the moisture content and cannot simultaneously address the issues of insufficient beneficial bacteria and low substrate utilization efficiency. On the other hand, single-agent treatments suffer from problems related to cost, adaptability, and poor stability of efficacy in practical applications.

[0004] Fresh grass press liquid is a liquid product obtained by mechanically pressing fresh forage green tissue. Fresh grass press liquid mainly contains water, as well as a certain amount of soluble sugars, vitamins, minerals and other nutrients. In addition, it also contains attached lactic acid bacteria. The main functions of lactic acid bacteria in silage fermentation or feed are as follows: (1) Lactic acid bacteria can secrete a variety of digestive enzymes such as protease, amylase and lipase, which can decompose the macromolecular nutrients in feed (such as protein, starch, etc.) into smaller molecules (such as amino acids, glucose, etc.) that are more easily absorbed, thereby improving the conversion rate and utilization rate of feed; (2) Lactic acid bacteria produce lactic acid, organic acid and other substances through metabolism, which can lower the pH value and inhibit the growth of harmful bacteria; (3) Lactic acid bacteria can stimulate the local immune response in the intestine and increase the antibody level, thereby enhancing the animal's immunity and disease resistance; (4) When lactic acid bacteria are used for fermented feed, the sour aroma produced by lactic acid bacteria metabolism can improve the palatability of the feed and increase the animal's feed intake.

[0005] Fresh grass press liquid is a byproduct produced after pressing fresh grass. Fresh grass with excessively high water content is prone to fermentation failure. Therefore, pressing removes some of the water from the fresh grass, increasing its dry matter content and creating suitable moisture conditions for silage. The liquid produced after pressing is called fresh grass press liquid. Typically, fresh grass press liquid is directly discharged, which not only wastes its nutrients but may also pollute surrounding soil and water sources.

[0006] A search revealed no reports of using fresh grass extract as an exogenous fermentation agent to improve the quality of corn kernel rehydrated silage. Summary of the Invention

[0007] In view of the problems of easy gas production, slow fermentation start-up, large fermentation loss and poor aerobic stability in the process of rehydrating and ensiling corn kernels, the purpose of this invention is to provide the application of fresh grass pressing liquid in improving the quality of dried corn kernel rehydration and ensiling.

[0008] The aforementioned application refers to the liquid product obtained by mechanically pressing fresh forage grass green tissue as raw material.

[0009] The fresh grass mentioned in the above applications refers to one or more of the following plants: forage wheat crops, forage corn, forage sorghum, Napier grass, forage rape, chicory, sow thistle, clematis, comfrey, arrowroot pea, glossy purple sweet potato, milkvetch, white clover, or red clover.

[0010] In the above applications, the fresh green tissue refers to tender stems and / or leaves.

[0011] This invention also provides a method for improving the quality of rehydrated silage of dried corn kernels using fresh grass press liquor, comprising the following steps: (1) Corn kernel crushing: use a pulverizer with a screen aperture of 2-8 mm to crush the dried corn kernels into corn granules; test the moisture content of the corn kernels; (2) Preparation of fresh grass extract: cut the grass and leave a stubble of 10-20cm, then chop the cut grass; then send it to the press by manual or conveyor device for pressing, and the liquid obtained by pressing is the fresh grass extract; test the water content of the obtained fresh grass extract. (3) Grain rehydration and mixing: The amount of fresh grass press liquid to be added is calculated according to the weight percentage ratio of the target moisture content of the corn grain rehydration silage mixture to 25% to 40%; the calculation formula for the amount of fresh grass press liquid to be added is as follows: Where X is the required mass of fresh grass extract (unit: kg), Y is the mass of corn kernels (unit: kg), Kw is the moisture content of corn kernels (unit: Kw%), Jw is the moisture content of fresh grass extract (unit: Jw%), and Mw is the target moisture content of the corn kernel rehydrated silage mixture (unit: Mw%). Place the corn kernels obtained in step (1) into a feed mixer, then add the fresh grass pressing liquid obtained in step (2) into the feed mixer according to the proportion, and stir and mix evenly to obtain a corn kernel rehydrated silage mixture. (4) Filling, compacting and sealing: The mixture obtained in step (3) is filled in layers into silage bags or silage barrels, compacted and sealed to achieve a filling density of 850-1100 kg / m³. 3 ; (5) Storage and fermentation: Place the sealed silage bags or silage buckets in a cool and dry place for anaerobic storage to prevent insect pests, rodents or rainwater from invading. The anaerobic storage time is 90 to 180 days to obtain corn kernel rehydrated silage fermentation products.

[0012] In the above method, the corn kernels mentioned in step (1) can be hard endosperm corn kernels or aged corn kernels.

[0013] In the above method, the moisture content of the dried corn kernels in step (1) is usually 10% to 15%.

[0014] In the above method, the moisture content of the fresh grass in step (2) is greater than 80%, and the fresh grass is free from obvious diseases and pests.

[0015] The fresh grass mentioned in step (2) of the above method refers to one or more of the following plants: forage wheat crops, forage corn, forage sorghum, Napier grass, forage rape, chicory, sow thistle, clematis, comfrey, arrowhead pea, glossy purple sweet potato, milkvetch, white clover or red clover.

[0016] In the above method, the addition of the fresh grass pressing liquid in step (3) and the stirring and mixing are carried out simultaneously.

[0017] The mixing and sealing process described in steps (3) and (4) of the above method must be completed within 6 hours after the fresh grass pressing liquid is prepared.

[0018] If the fresh grass extract prepared in step (2) of the above method is not rehydrated and mixed with corn kernels within 6 hours after preparation, it must be sealed and stored first. The method of sealing and storing is to fill the tank with the fresh grass extract (to reduce the air in the tank) and tighten the tank lid; and the sealing of the corn kernel rehydrated silage described in steps (3) and (4) must be completed within 24 hours after the fresh grass extract is prepared.

[0019] Compared with the prior art, the beneficial effects or advantages of the present invention are as follows: (1) The method of the present invention realizes the recovery and resource reuse of the by-product fresh grass pressing liquid in the process of fresh grass silage processing, which avoids resource waste and reduces environmental pollution. (2) The fermentation process in the method of the present invention basically does not produce gas, which reduces fermentation loss and reduces the loss of dry matter in the grains. (3) The lactic acid bacteria and soluble sugars contained in the fresh grass pressing liquid of the present invention promote the rapid start of lactic acid fermentation in the rehydrated corn kernel silage, accelerate the decrease of pH value, and at the same time, the various enzymes secreted by the lactic acid bacteria promote the fermentation of corn kernels and improve the fermentation quality. (4) The lactic acid bacteria present in the fresh grass pressing liquid of the present invention can inhibit the growth of harmful microorganisms and prolong the aerobic stability of silage after opening. (5) The acidic aroma produced by the metabolism of lactic acid bacteria in the method of the present invention can improve the palatability of feed and increase the animal's feed intake. (6) The fresh grass in the method of the present invention has a wide range of sources, simple preparation process, low cost, and is suitable for widespread application in feed production and breeding practices. Detailed Implementation

[0020] The present invention will be further described below with reference to specific embodiments, but is not limited thereto. Unless otherwise specified, the methods described in the embodiments are conventional methods.

[0021] Example 1: Experiment on the preparation of corn kernel rehydrated silage using fresh sow thistle extract. Follow these steps: (1) Corn kernel crushing: The dried corn kernels were crushed using a pulverizer (Lefeng 280 universal hammer mill). The screen aperture of the pulverizer was 3 mm, resulting in corn kernels with a diameter of less than 3 mm. The moisture content of the corn kernels was measured, and the result showed that the moisture content was 13%.

[0022] (2) Preparation of fresh grass pressing liquid: During the rosette stage of bitter lettuce, the stubble is cut with a 10cm stubble; then the above-ground tissue of the fresh bitter lettuce is immediately chopped using a pulverizer and transferred to a press (Ganggu Oulong press) for mechanical pressing. The liquid obtained is the fresh bitter lettuce pressing liquid; the water content of the fresh bitter lettuce pressing liquid was measured and the result was 94.87%.

[0023] (3) Grain rehydration and mixing: First, calculate the amount of fresh sow thistle extract to be added, and set the moisture content of the corn kernel rehydration silage mixture to 32%. The mass of fresh sow thistle extract to be added per 1000 kg of corn kernels is calculated as follows: The corn kernels obtained in step (1) were placed in a feed mixer. Then, the bitter lettuce extract obtained in step (2) was slowly poured into the feed mixer containing the corn kernels, according to the ratio of 302.2 kg of fresh bitter lettuce extract per 1000 kg of corn kernels. The mixture was stirred while pouring to ensure thorough mixing, resulting in a mixture of corn kernels and fresh bitter lettuce extract. A sample was taken from the mixture, and its moisture content was measured to be 32.46%. (4) Filling, compacting and sealing: Immediately fill the mixture obtained in step (3) into polyethylene silage bags, compact, degas and vacuum seal, with a density of 894 kg / m³. 3 .

[0024] The process from the preparation of the fresh bitter lettuce extract in step (2) to the sealing in step (4) must be completed within 6 hours. (5) Storage and fermentation: The silage bags are anaerobically fermented for 120 days at room temperature in the dark to obtain the corn kernel rehydrated silage fermentation product.

[0025] Example 2: Experiment on the preparation of corn kernel rehydrated silage using fresh arrowhead pea grass press liquid according to the present invention. Follow these steps: (1) Corn kernel crushing: Commercially available dried corn kernels were crushed using a pulverizer (Lefeng 280 universal hammer mill). The pulverizer had a screen aperture of 3 mm, resulting in corn kernels with a diameter of less than 3 mm. The moisture content of the corn kernels was measured, and the result showed that the moisture content was 13%.

[0026] (2) Preparation of fresh grass extract: At the initial flowering stage of *Vicia sativa*, the stubble was cut with a 10cm stubble. The fresh above-ground tissues were immediately chopped using a shredder and transferred to a press (a Ganggu Oulong press, purchased from the market) for mechanical pressing. The liquid obtained from pressing is the fresh grass extract of *Vicia sativa*. The water content of the fresh grass extract was measured, and the result showed that its water content was 95.21%.

[0027] (3) Corn kernel rehydration and mixing: First calculate the amount of fresh arrowroot grass juice to be added. Set the moisture content of the corn kernel rehydration silage mixture to 32%. The formula for calculating the amount of fresh arrowroot grass juice to be added per 1000 kg of corn kernels is as follows: The corn kernels obtained in step (1) were placed in a feed mixer. Then, the arrow-shaped pea pressing liquid obtained in step (2) was slowly poured into the feed mixer containing the corn kernels at a ratio of 300.6 kg of fresh arrow-shaped pea grass pressing liquid per 1000 kg of corn kernels, while stirring continuously to ensure thorough mixing, resulting in a mixture of corn kernels and fresh arrow-shaped pea grass pressing liquid. A sample was taken from the mixture, and its moisture content was measured to be 33.04%. (4) Filling, compacting and sealing: Immediately fill the mixture obtained in step (3) into polyethylene silage bags, compact, degas and vacuum seal, with a density of 876 kg / m³. 3 .

[0028] The process from the preparation of fresh arrowhead pea grass extract in step (2) to the sealing in step (4) must be completed within 6 hours. (5) Storage and fermentation: The silage bags are anaerobic fermented at room temperature and in the dark for 120 days to obtain the corn kernel rehydrated silage fermentation product.

[0029] Comparative Example 1: Experiment on the preparation of corn kernel rehydration silage using water Follow these steps: (1) Corn kernel crushing: The dried corn kernels were crushed using a pulverizer with a screen aperture of 3 mm to obtain corn kernels with a diameter of less than 3 mm; the moisture content of the corn kernels was measured and found to be 13%.

[0030] (2) Preparation of clean water: Take fresh tap water, place it in the field, and expose it to sunlight for 3 days to prepare clean water without residual chlorine.

[0031] (3) Rehydration and mixing of corn kernels: The moisture content of the rehydrated corn kernels for silage is set to 32%. The calculation of the mass of water to be added per 1000 kg of corn kernels is as follows: The corn kernels obtained in step (1) were introduced into a feed mixer. Then, water was slowly added to the mixer at a ratio of 279.4 kg of water per 1000 kg of corn kernels, while stirring continuously until the mixture was homogeneous, resulting in a mixture of rehydrated corn kernels for silage. The moisture content of the mixture was tested and found to be 32.14%.

[0032] (4) Filling, compacting and sealing: The mixture obtained in step (3) is filled into polyethylene silage bags, compacted, vented and vacuum-sealed. The measured density is 882 kg / m³. 3 .

[0033] Steps (2) to (4) above must be completed within 3 hours.

[0034] (5) Storage and fermentation: Place the silage bags in room temperature and dark conditions for anaerobic fermentation for 120 days to obtain corn kernel rehydrated silage fermentation product.

[0035] Example 4: Comparative Analysis of Results of Experiments on Improving the Quality of Rehydrated Corn Kernels and Silage Using Fresh Grass Pressing Liquid. (a) Experimental materials: Corn kernel rehydrated silage fermentation products obtained in Examples 1, 2 and 3.

[0036] (II) Analysis of Experimental Items, Methods and Results 1. Gas production: Observe the gas production of the silage bags with the naked eye.

[0037] The results (see Table 1) show that the fresh grass extract from *Sonchus oleraceus* and *Vigna arvense* used in this invention for rehydrating corn kernels into silage produced virtually no gas during fermentation. In contrast, in Comparative Example 1, using water for rehydrating corn kernels into silage resulted in significant gas production during fermentation. This indicates that the fresh grass extract used in this invention is significantly more effective than the water group in improving the fermentation quality of rehydrating corn kernel silage.

[0038] 2. Determination of dry matter loss rate: The dry matter loss rate was determined by weighing method.

[0039] The results (see Table 1) show that the dry matter loss rate of the water group was as high as 12.14%, while the dry matter loss rates of the fresh sow thistle extract group and the fresh pea shoot extract group were only 6.42% and 6.14%, respectively. This indicates that the nutrient loss of the water group during fermentation was significantly greater than that of the fresh sow thistle and fresh pea shoot extract groups.

[0040] 3. pH value and lactic acid content determination: pH value was determined according to DB15 / T 1458-2018.

[0041] The results (see Table 1) showed that the pH value of the water group was 5.10, significantly higher than that of the *Sonchus oleraceus* fresh grass extract group (3.81) and the *Vigna arvense* fresh grass extract group (3.74), indicating that the acidification degree of the water group was insufficient and the fermentation quality was poor. This demonstrates that the fresh grass extract of this invention, as an exogenous fermentation agent, has a good effect on improving the quality of rehydrated corn silage.

[0042] 4. Lactic acid content determination: The lactic acid content shall be determined in accordance with DB15 / T 1458-2018.

[0043] The results (see Table 1) showed that the lactic acid content in the water group was only 5.18 g / kg DM, which was lower than that in the fresh sow thistle extract group (6.37 g / kg DM) and the fresh pea shoot extract group (6.74 g / kg DM). This indicates that the lactic acid fermentation level of the present invention using fresh herb extract as an exogenous fermenting agent was significantly higher than that in the control water group.

[0044] 5. Aerobic stability test: The test method is as follows: Place the fermented sample in a room temperature environment and expose it to the air. Measure and record the sample temperature (the thermometer should be inserted 5 cm from the sample surface and not move, with an accuracy of 0.1℃) and room temperature change every 8 hours. When the sample temperature is ≥2℃ (or ≥1℃) higher than the ambient temperature, this time period is the aerobic stability time. The longer the aerobic stability time, the better the aerobic stability of the silage.

[0045] The results (see Table 1) show that the aerobic stability of the water group was only 10 days (ΔT=1℃) or 20 days (ΔT=2℃), while that of the fresh grass press liquor group was greater than 30 days. This indicates that the water group was more prone to secondary heating and spoilage after opening, and the samples showed obvious mold growth. In contrast, the present invention utilizes fresh grass press liquor as an exogenous fermentation agent to obtain corn kernel rehydrated silage products with good aerobic stability and no spoilage.

[0046] Table 1. Comparative Results of Improving the Quality of Rehydrated Corn Silage Using Fresh Grass Pressing Liquid in This Invention Note: *If aerobic stability is calculated based on ΔT=1℃, #If aerobic stability is calculated based on ΔT=2℃.

[0047] In summary, the present invention demonstrates that using fresh grass press liquid for corn kernel rehydration silage is significantly superior to the control water group in reducing dry matter loss, promoting acidification, increasing lactic acid accumulation, and prolonging aerobic stability.

Claims

1. Application of fresh grass pressing liquid in improving the quality of rehydrated corn kernels for silage.

2. The application according to claim 1, characterized in that, The fresh grass press liquid mentioned therein refers to the liquid product obtained by mechanically pressing fresh forage grass green tissue as raw material.

3. The application according to claim 1, characterized in that, The fresh grass mentioned refers to one or more of the following plants: forage wheat crops, forage corn, forage sorghum, Napier grass, forage rape, chicory, sow thistle, clematis, comfrey, arrowroot pea, glossy purple sweet potato, milkvetch, white clover, or red clover.

4. A method for improving the quality of rehydrated silage of dried corn kernels using fresh grass pressing liquid, characterized in that, Includes the following steps: (1) Corn kernel crushing: use a pulverizer with a screen aperture of 2-8 mm to crush the dried corn kernels into corn granules; test the moisture content of the corn kernels; (2) Preparation of fresh grass extract: cut the grass and leave a stubble of 10-20cm, then chop the cut grass; then send it to the press by manual or conveyor device for pressing, and the liquid obtained by pressing is the fresh grass extract; test the water content of the obtained fresh grass extract. (3) Corn kernel rehydration and mixing: Calculate the amount of fresh grass press liquid to be added based on the target moisture content of the corn kernel rehydration silage mixture being 25% to 40% by weight percentage; the calculation formula for the amount of fresh grass press liquid to be added is as follows: Where X is the required mass of fresh grass extract (unit: kg), Y is the mass of corn kernels (unit: kg), Kw is the moisture content of corn kernels (unit: Kw%), Jw is the moisture content of fresh grass extract (unit: Jw%), and Mw is the target moisture content of the corn kernel rehydrated silage mixture (unit: Mw%). Place the corn kernels obtained in step (1) into a feed mixer, then add the fresh grass pressing liquid obtained in step (2) into the feed mixer according to the proportion, and stir and mix evenly to obtain a corn kernel rehydrated silage mixture. (4) filling, compacting and sealing: the mixture obtained in step (3) is layered into a silage bag or silage barrel, compacted and sealed, so that the filling density reaches 850-1100 kg / m 3 ​ (5) Storage and fermentation: Place the sealed silage bags or silage buckets in a cool and dry place for anaerobic storage. The anaerobic storage time is 90 to 180 days to obtain corn kernel rehydrated silage fermentation product.

5. The method according to claim 4, characterized in that, The corn kernels mentioned in step (1) are hard endosperm corn kernels or aged corn kernels.

6. The method according to claim 4, characterized in that, The fresh grass mentioned in step (2) refers to one or more of the following plants: forage wheat crops, forage corn, forage sorghum, Napier grass, forage rape, chicory, sow thistle, clematis, comfrey, arrowhead pea, glossy purple sweet potato, milkvetch, white clover or red clover.

7. The method according to claim 4, characterized in that, The addition of the fresh grass pressing liquid in step (3) and the mixing are carried out simultaneously.

8. The method according to claim 4, characterized in that, The mixing and sealing process described in steps (3) and (4) must be completed within 6 hours after the fresh grass pressing liquid is prepared.

9. The method according to claim 4, characterized in that, If the fresh grass extract prepared in step (2) is not mixed with corn kernels for rehydration within 6 hours after preparation, it must be sealed and stored. The method of sealing and storing is to fill the tank with the fresh grass extract (to reduce air in the tank) and tighten the tank lid. The mixing and sealing of the corn kernels for rehydration silage described in steps (3) and (4) must be completed within 24 hours after the fresh grass extract is prepared.

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