Preparation method and application of corn germ meal extract
The extract of corn germ meal from corn germ meal through a specific enzymatic lysis process solved the problem that corn germ meal failed to effectively improve the heat stress performance in rabbit breeding, and achieved significant anti-thermal stress effect and economic benefits.
Patent Information
- Application Number
- CN202510648365.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-20
- Publication Date
- 2025-08-26
AI Technical Summary
The existing corn germ meal has failed to effectively improve heat stress performance in rabbit breeding, resulting in a decline in reproductive performance, hindered growth performance and an increase in health problems.
The extract of corn germ meal from corn germ meal by a specific enzymatic lysis process, including crushing, enzymatic lysis, compression, ultrafiltration and spray drying, was prepared to improve the anti-thermal stress performance of rabbits.
Significantly improve the anti-thermal stress performance of rabbits in a heat-stress environment, improve the feed intake and yield rate of female rabbits, enhance the growth of levitra, improve the sperm quality of male rabbits, reduce rectal temperature, and improve breeding efficiency.
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Figure CN120531053A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of corn germ meal extracts, in particular to a preparation method and application of the corn germ meal extracts. Background Art
[0002] Heat stress is a common problem in animal husbandry, especially rabbit farming. Heat stress refers to the nonspecific response animals experience when exposed to temperatures exceeding their natural regulatory capacity. This response can negatively impact rabbits' physiology and productivity in a variety of ways, including but not limited to the following:
[0003] Reduced reproductive performance: Heat stress can significantly reduce the reproductive performance of female rabbits, manifesting as decreased litter size, embryonic malformation, and miscarriage. Simultaneously, the sperm quality of male rabbits can be severely affected, leading to decreased sperm motility and increased rates of deformities, which in turn affects the reproductive efficiency of the entire rabbit population.
[0004] Impaired growth performance: Heat stress can reduce rabbits' feed intake, leading to insufficient nutrient intake, which in turn affects their growth rate and development. Especially for young rabbits, slow growth will directly affect their later production performance and economic benefits.
[0005] Increased health problems: Long-term exposure to heat stress can suppress the rabbit’s immune system, making it more susceptible to disease and increasing the difficulty and cost of disease prevention and control during breeding.
[0006] Although corn germ meal is a common animal feed ingredient and widely used in rabbit farming, relatively little research and application has been conducted on its application in improving rabbits' resistance to heat stress. Corn germ meal, a byproduct of oil extraction from corn germ, is rich in nutrients such as protein and cellulose. However, traditional corn germ meal feed is not ideal for addressing heat stress in rabbits.
[0007] Therefore, developing a feed additive that can effectively improve the rabbit's resistance to heat stress is of great significance for improving the economic benefits and animal welfare of rabbit farming. Summary of the Invention
[0008] In response to the technical problems in the above-mentioned prior art, the present invention provides a corn germ meal extract prepared by a specific enzymatic hydrolysis process, and applies it to rabbit feed, in order to solve the reproduction, growth and health problems of rabbits under heat stress environment.
[0009] To achieve the above object, the present invention provides the following technical solutions:
[0010] A method for preparing a corn germ meal extract comprises the following steps:
[0011] S1: Grind corn germ meal into 100-200 mesh, mix with water according to mass, and prepare corn germ meal solution;
[0012] S2: adjusting the pH value of the corn germ meal solution to 6.5-7.5, adding a composite protease, and performing enzymatic hydrolysis at 45-50° C. for 50-90 minutes to obtain an enzymatic hydrolyzate A;
[0013] S3: adjusting the pH value of the enzymatic hydrolysate A to 8.0-9.0, adding alkaline protease, performing enzymatic hydrolysis at 48-54° C. for 20-40 minutes, centrifuging, and collecting the supernatant to obtain enzymatic hydrolysate B;
[0014] S4: filtering the enzymatic hydrolyzate B to obtain a filtrate and a filter cake, ultrafiltering the filtrate, and collecting the effluent;
[0015] S5: spray-drying the effluent to obtain the corn germ meal extract.
[0016] Preferably, in S1, the mass ratio of the crushed corn germ meal to water is 1:(10-20).
[0017] Preferably, in S2, the composite protease comprises cellulase and papain, the cellulase and papain are mixed in a ratio of 1:(1-5), and the added amount of the composite protease is 0.2-0.5% of the mass of the corn germ meal solution.
[0018] Preferably, in S3, the amount of alkaline protease added is 0.3-0.7% of the mass of the enzymatic solution A.
[0019] Preferably, in S4, the mesh size of the filter cloth for the pressure filtration is 150-250 mesh, and the molecular weight cut-off of the ultrafiltration is 5000-8000 Da.
[0020] Preferably, in S5, the air inlet temperature of the spray drying is 200-240°C, and the air outlet temperature is 70-90°C.
[0021] The present invention also provides an application of a corn germ meal extract for improving the heat stress resistance, reproductive performance and growth performance of rabbits under a heat stress environment. The corn germ meal extract is obtained by the above-mentioned preparation method.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] The preparation method of the corn germ meal extract of the present invention and its application in rabbit feed have significant comprehensive benefits:
[0024] In terms of preparation methods, a specific enzymatic hydrolysis process can efficiently extract functional active ingredients from corn germ meal that improve rabbits' resistance to heat stress. This method not only improves extraction efficiency but also ensures the optimal content and properties of the active ingredients in the extract by precisely controlling the enzymatic hydrolysis conditions, thereby enhancing the extract's effectiveness. Furthermore, using corn germ meal, a widely available and inexpensive raw material, reduces production costs, improves resource utilization, and demonstrates high economic efficiency and scalability.
[0025] In terms of application effects, adding this extract to rabbit feed can significantly improve several key performance indicators of rabbits in heat stress environments. It can effectively reduce the rabbit's rectal temperature, alleviate the adverse effects of heat stress on the rabbit's body, and enhance the rabbit's ability to adapt to high temperature environments. In addition, this extract can also increase the feed intake of female rabbits during pregnancy and lactation, thereby increasing the female rabbit's litter size and the number and quality of the offspring. At the same time, it provides the necessary nutritional support for the growth and development of the offspring, promotes the rapid growth of the offspring, shortens the breeding cycle, and improves breeding efficiency. In addition, it significantly improves the sperm quality of breeding male rabbits, including indicators such as sperm motility, ejaculation volume, and deformity rate, thereby improving the fertilization success rate and increasing the number and quality of offspring. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 This is a table of rectal temperature data of female rabbits in the second and third weeks of the preparation method and application of the corn germ meal extract of the present invention;
[0027] Figure 2 A data table showing the average daily feed intake of female rabbits during pregnancy and lactation in the preparation method and application of the corn germ meal extract of the present invention;
[0028] Figure 3 A data table of rabbit farrowing rates in the preparation method and application of a corn germ meal extract according to the present invention;
[0029] Figure 4 A data table of rabbit weights in the preparation method and application of a corn germ meal extract according to the present invention;
[0030] Figure 5 This is a preparation method of the corn germ meal extract described in the present invention and a data table of sperm quality of breeding male rabbits in its application. DETAILED DESCRIPTION
[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0032] Example 1: Preparation of corn germ meal extract.
[0033] Pretreatment: Grind the corn germ meal into 150 mesh and mix it with water at a mass ratio of 1:15 to prepare a corn germ meal solution.
[0034] First enzymatic hydrolysis: The pH value of the corn germ meal solution was adjusted to 7.0 (using 0.1 mol / L sodium hydroxide solution), and a composite protease (cellulase and papain mixed in a ratio of 1:4) was added according to 0.3% of the mass of the corn germ meal solution. The enzymatic hydrolysis was carried out at 50° C. for 1 hour to obtain enzymatic hydrolyzate A.
[0035] Second enzymatic hydrolysis: adjust the pH value of enzymatic hydrolysate A to 8.0 (using 0.1 mol / L sodium hydroxide solution), add alkaline protease according to 0.5% of the mass of enzymatic hydrolysate A, enzymatic hydrolysis at 50°C for 30 minutes, and then centrifuge at 8000 rpm for 10 minutes, collect the supernatant, and obtain enzymatic hydrolysate B.
[0036] Filter pressing: The enzymatic hydrolyzate B is filtered through a 200-mesh filter cloth using a plate and frame filter to obtain a filtrate and a filter cake. The filter cake can be dried and crushed to produce corn germ meal feed.
[0037] Ultrafiltration: The filtrate was filtered through an ultrafiltration membrane with a molecular weight cut-off of 6000 Da, and the permeate was collected.
[0038] Spray drying: The permeate was spray dried with an air inlet temperature of 220°C and an air outlet temperature of 80°C to obtain a corn germ meal extract.
[0039] Through a specific enzymatic hydrolysis process, a corn germ meal extract with functional active ingredients that improve rabbits' resistance to heat stress can be efficiently extracted from corn germ meal. This method not only improves extraction efficiency but also ensures optimal content and properties of the active ingredients in the extract by precisely controlling the enzymatic hydrolysis conditions, thereby enhancing the extract's effectiveness. Furthermore, by using corn germ meal, a widely available and inexpensive raw material, it reduces production costs, improves resource utilization, and demonstrates high economic efficiency and scalability.
[0040] Example 2: Application of corn germ meal extract to improve the heat stress resistance, reproductive performance and growth performance of rabbits under heat stress environment.
[0041] 50 female rabbits in good condition, similar weight and the same parity and 50 male rabbits in good condition and similar weight were selected. The rabbits were weighed to ensure that there was no significant difference in the weight of each group of rabbits. The experiment was carried out under controlled experimental conditions. All experimental animals were kept in the same rabbit house. The average temperature and humidity index (THI) of the rabbit house was controlled between 28.9 and 30.0 every day, so that the experimental animals were in a severe heat stress environment. The experimental animals were fed freely and had automatic drinking water. The female rabbits and breeding male rabbits were randomly divided into five groups (10 in each group) and fed in groups, namely experimental group 1, experimental group 2, experimental group 3, experimental group 4 and control group. The experimental groups were fed as follows, and the control group was only fed with basic feed.
[0042] Test results:
[0043] The basic feed formula of the control group was: 27% corn, 7% wheat bran, 15% bran, 8% DDGS, 3% oil cake, 2% cottonseed meal, 8% soybean meal, 20% alfalfa, 12% oat straw, 5% rice bran, 0.5% salt, 1.2% calcium powder, and 0.3% calcium hydrogen phosphate.
[0044] Experimental Group 1: Preparation of Corn Germ Meal Extract (Basic)
[0045] Pretreatment: Grind the corn germ meal into 150 mesh and mix it with water at a mass ratio of 1:15 to prepare a corn germ meal solution.
[0046] First enzymatic hydrolysis: The pH value of the corn germ meal solution was adjusted to 7.0 (using 0.1 mol / L sodium hydroxide solution), and a composite protease (cellulase and papain mixed in a ratio of 1:4) was added according to 0.3% of the mass of the corn germ meal solution. The enzymatic hydrolysis was carried out at 50° C. for 1 hour to obtain enzymatic hydrolyzate A.
[0047] Second enzymatic hydrolysis: adjust the pH value of enzymatic hydrolysate A to 8.0 (using 0.1 mol / L sodium hydroxide solution), add alkaline protease according to 0.5% of the mass of enzymatic hydrolysate A, enzymatic hydrolysis at 50°C for 30 minutes, and then centrifuge at 8000 rpm for 10 minutes, collect the supernatant, and obtain enzymatic hydrolysate B.
[0048] Filter pressing: The enzymatic hydrolyzate B is filtered through a 200-mesh filter cloth using a plate and frame filter to obtain a filtrate and a filter cake. The filter cake can be dried and crushed to produce corn germ meal feed.
[0049] Ultrafiltration: The filtrate was filtered through an ultrafiltration membrane with a molecular weight cut-off of 6000 Da, and the permeate was collected.
[0050] Spray drying: The permeate was spray dried with an air inlet temperature of 220°C and an air outlet temperature of 80°C to obtain a corn germ meal extract.
[0051] Experimental Group 2: Preparation of corn germ meal extract (higher enzyme content)
[0052] Pretreatment: Grind the corn germ meal into 150 mesh and mix it with water at a mass ratio of 1:15 to prepare a corn germ meal solution.
[0053] First enzymatic hydrolysis: The pH value of the corn germ meal solution was adjusted to 7.0, and a composite protease (cellulase and papain mixed in a ratio of 1:4) was added according to 0.8% of the mass of the corn germ meal solution. The enzymatic hydrolysis was carried out at 50° C. for 1 hour to obtain enzymatic hydrolyzate A.
[0054] Second enzymatic hydrolysis: the pH value of enzymatic hydrolysate A was adjusted to 8.0, alkaline protease was added according to 0.5% of the mass of enzymatic hydrolysate A, and enzymatic hydrolysis was carried out at 50°C for 30 minutes, followed by centrifugation at 8000 rpm for 10 minutes, and the supernatant was collected to obtain enzymatic hydrolysate B.
[0055] Filter pressing: The enzymatic hydrolyzate B is filtered through a 200-mesh filter cloth using a plate and frame filter to obtain a filtrate and a filter cake. The filter cake can be dried and crushed to produce corn germ meal feed.
[0056] Ultrafiltration: The filtrate was filtered through an ultrafiltration membrane with a molecular weight cut-off of 6000 Da, and the permeate was collected.
[0057] Spray drying: The permeate was spray dried with an air inlet temperature of 220°C and an air outlet temperature of 80°C to obtain a corn germ meal extract.
[0058] Experimental Group 3: Preparation of Corn Germ Meal Extract (Single Cellulase)
[0059] Pretreatment: Grind the corn germ meal into 150 mesh and mix it with water at a mass ratio of 1:15 to prepare a corn germ meal solution.
[0060] Enzyme hydrolysis: the pH value of the corn germ meal solution was adjusted to 7.0, cellulose protease was added according to 0.3% of the mass of the corn germ meal solution, and enzymatic hydrolysis was carried out at 50° C. for 1 hour to obtain an enzymatic hydrolyzate.
[0061] Filter pressing: The enzymatic hydrolysate is filtered through a 200-mesh filter cloth using a plate and frame filter to obtain a filtrate and a filter cake. The filter cake can be dried and crushed to produce corn germ meal feed.
[0062] Ultrafiltration: The filtrate was filtered through an ultrafiltration membrane with a molecular weight cut-off of 6000 Da, and the permeate was collected.
[0063] Spray drying: The permeate was spray dried with an air inlet temperature of 220°C and an air outlet temperature of 80°C to obtain a corn germ meal extract.
[0064] Experimental Group 4: Preparation of Corn Germ Meal Extract (Longer First Enzymatic Hydrolysis Time)
[0065] Pretreatment: Grind the corn germ meal into 150 mesh and mix it with water at a mass ratio of 1:15 to prepare a corn germ meal solution.
[0066] First enzymatic hydrolysis: The pH value of the corn germ meal solution was adjusted to 7.0, and a composite protease (cellulase and papain mixed in a ratio of 1:4) was added according to 0.3% of the mass of the corn germ meal solution. The enzymatic hydrolysis was carried out at 50° C. for 1.5 hours to obtain enzymatic hydrolyzate A.
[0067] Second enzymatic hydrolysis: the pH value of enzymatic hydrolysate A was adjusted to 8.0, alkaline protease was added according to 0.5% of the mass of enzymatic hydrolysate A, and enzymatic hydrolysis was carried out at 50°C for 30 minutes, followed by centrifugation at 8000 rpm for 10 minutes, and the supernatant was collected to obtain enzymatic hydrolysate B.
[0068] Filter pressing: The enzymatic hydrolyzate B is filtered through a 200-mesh filter cloth using a plate and frame filter to obtain a filtrate and a filter cake. The filter cake can be dried and crushed to produce corn germ meal feed.
[0069] Ultrafiltration: The filtrate was filtered through an ultrafiltration membrane with a molecular weight cut-off of 6000 Da, and the permeate was collected.
[0070] Spray drying: The permeate was spray dried with an air inlet temperature of 220°C and an air outlet temperature of 80°C to obtain a corn germ meal extract.
[0071] Among them: Experimental Group 1: 300 g of the corn germ meal extract prepared in Example 1 was added to every 1000 kg of basic feed.
[0072] Experimental Group 2: 300 g of the corn germ meal extract prepared in Example 2 was added to every 1000 kg of the basic feed.
[0073] Experimental Group 3: 300 g of the corn germ meal extract prepared in Example 3 was added to every 1000 kg of the basic feed.
[0074] Experimental Group 4: 300 g of the corn germ meal extract prepared in Example 4 was added to every 1000 kg of the basic feed.
[0075] Control group: basic feed.
[0076] Corn germ meal extract was added to the basal feed 2 weeks before breeding, with the breeding day as the first day.
[0077] The rectal temperature of the female rabbits was measured at the 2nd and 3rd week of the experiment, and the average daily feed intake, litter size, weight of 1-week-old, 2-week-old and 3-week-old female rabbits were recorded. The sperm motility, ejaculation volume and deformity rate of the breeding male rabbits were tested one day before mating.
[0078] Statistical analysis: The experimental data were analyzed using Excel 2013, SPSS 26.0, and GraphPad Prism 9 software. The results were expressed as "mean ± standard error", and P < 0.05 was used as the standard for judging significant differences.
[0079] Analysis results:
[0080] (1) Rectal temperature of female rabbits at the second and third weeks
[0081] Rectal temperature of female rabbits at 2nd and 3rd week Figure 1 As shown, at the second week, the rectal temperature of rabbits in experimental groups 1-4 was significantly lower than that in the control group (p < 0.05), among which there were significant differences between experimental group 1 and experimental groups 2, 4 and the control group (p < 0.05), the rectal temperature of experimental group 1 was lower than that of experimental group 3, but the difference was not significant (p > 0.05), the rectal temperature of experimental group 2 was significantly higher than that of experimental group 3 (p < 0.05) and lower than that of experimental group 4, but there was no significant difference (p > 0.05), and the rectal temperature of experimental group 3 was significantly lower than that of experimental group 4 (p < 0.05); at the fourth week, the rectal temperature of experimental group 1 was significantly lower than that of experimental group 3 (p < 0.05). The rectal temperatures of rabbits in groups 1-4 were significantly lower than those in the control group (p < 0.05). There were significant differences between experimental group 1 and experimental groups 2 and 3 (p < 0.05), and no significant difference between experimental group 1 and experimental group 4 (p > 0.05). There was no significant difference between experimental group 2 and experimental group 3 (p > 0.05), and there was a significant difference between experimental group 2 and experimental group 4 (p < 0.05). There was a significant difference between experimental group 3 and experimental group 4 (p < 0.05). This shows that the use of corn germ meal extract can effectively reduce rectal temperature, thereby improving the rabbit's resistance to heat stress.
[0082] (2) Average daily feed intake during gestation and lactation
[0083] The results are as follows Figure 2 As shown, the average daily feed intake of pregnant and lactating rabbits in experimental groups 1-4 was significantly higher than that in the control group (p < 0.05), and there were significant differences among the experimental groups (p < 0.05); this indicates that the use of corn germ meal extract can effectively increase the feed intake of pregnant and lactating rabbits.
[0084] (3) Fertility rate of female rabbits
[0085] The results are as follows Figure 3It can be seen that the litter birth rate of experimental groups 1-4 was significantly better than that of the control group (p < 0.05), experimental group 1 was significantly higher than that of experimental groups 2-4 (p < 0.05), and there was no significant difference between experimental groups 2-4 (p > 0.05); this shows that the use of corn germ meal extract can effectively improve the reproductive performance of female rabbits and increase their litter birth rate.
[0086] (4) Rabbit weight
[0087] The results are as follows Figure 4 As shown, the weights of the pups in experimental groups 1-4 were significantly higher than those in the control group (p < 0.05); for the weights of the pups at 1 week old, except for experimental group 2 which had no significant difference with experimental groups 3 and 4 (p > 0.05), there were significant differences among the other experimental groups (p < 0.05); for the weights of the pups at 2 weeks old, there were significant differences among the experimental groups (p < 0.05); for the weights of the pups at 3 weeks old, there was no significant difference between experimental groups 2 and 3 (p > 0.05), and there were significant differences among the other experimental groups (p < 0.05); this indicates that the use of corn germ meal extract can effectively improve the growth status of pups.
[0088] (5) Sperm quality of breeding rabbits
[0089] Depend on Figure 5 It can be seen that the sperm quality of the breeding male rabbits in experimental groups 1-4 was significantly better than that in the control group (p < 0.05). For sperm motility, there was no significant difference between experimental groups 3 and 4 (p > 0.05), and there were significant differences between the other experimental groups (p < 0.05); for ejaculation volume, there was no significant difference between experimental groups 2 and 4 (p > 0.05), and there were significant differences between the other experimental groups (p < 0.05); for deformity rate, there was no significant difference between experimental groups 2 and 4 (p > 0.05), and there were significant differences between the other experimental groups (p < 0.05); this shows that the use of corn germ meal extract can effectively improve the sperm quality of breeding male rabbits, thereby improving reproductive performance.
[0090] Advantages of compound enzymatic hydrolysis process:
[0091] Comparison between experimental group 1 and experimental group 2 showed that the amount of compound protease added had a significant effect on the effect of the extract. The lower amount of compound protease added in experimental group 1 (0.3%) was able to achieve better results, while the higher amount of compound protease added in experimental group 2 (0.8%) was also able to significantly improve the rabbit's resistance to heat stress, but was slightly inferior to experimental group 1 in some indicators. This shows that the amount of enzyme added in the compound enzymatic hydrolysis process needs to be precisely controlled to achieve the best effect.
[0092] Experimental group 3 used only cellulase for enzymatic hydrolysis, and its effect was significantly lower than that of experimental group 1; this indicates that the composite enzymatic hydrolysis process (cellulase and papain used together) can more effectively extract functional active ingredients that improve the rabbit's resistance to heat stress, and the effect of single enzymatic hydrolysis is relatively poor.
[0093] Optimization of enzymatic hydrolysis time:
[0094] Comparison of experimental group 1 and experimental group 4 shows that the first enzymatic hydrolysis time has a significant effect on the effect of the extract; the shorter first enzymatic hydrolysis time (1 hour) in experimental group 1 can achieve better results, while the longer first enzymatic hydrolysis time (1.5 hours) in Example 4 leads to excessive enzymatic hydrolysis of the polypeptide, and the effect of the extract is slightly inferior to that of experimental group 1. This shows that time control is equally important during the enzymatic hydrolysis process. Excessive enzymatic hydrolysis time may lead to excessive degradation of the active ingredients and reduce the effect of the extract.
[0095] Experimental results show that adding this extract to the rabbit's basic feed can significantly improve the rabbit's resistance to heat stress, reproductive performance, and the growth performance of its offspring under heat stress. Specifically, the extract can significantly reduce the rabbit's rectal temperature and alleviate the adverse effects of heat stress on the rabbit's body. At the same time, it can also significantly increase the average daily feed intake of female rabbits during pregnancy and lactation, providing more nutrition for the female rabbits and helping to improve their reproductive performance. In addition, the extract can also significantly increase the female rabbit's litter rate, promote the rapid growth of offspring, and improve the sperm quality of breeding male rabbits, thereby increasing the fertilization success rate and increasing the number and quality of offspring. The realization of these effects not only helps to improve the economic benefits of rabbit farming, but also provides an effective heat stress resistance solution for the rabbit farming industry, with significant economic and social benefits.
[0096] In summary, the present method for preparing corn germ meal extract effectively extracts functional active ingredients that improve rabbits' heat stress resistance by precisely controlling the enzyme dosage, hydrolysis time, and hydrolysis conditions during the enzymatic hydrolysis process. Compared with existing technologies, the present method offers higher extraction efficiency, better results, and lower production costs, providing an effective heat stress resistance solution for the rabbit breeding industry with significant economic and social benefits.
[0097] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.
[0098] In the description of the present invention, unless otherwise specified, “plurality” means two or more; the orientations or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “inside”, “outside”, “front end”, “rear end”, “head” and “tail” are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.
[0099] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a corn germ meal extract, characterized in that: The following steps are involved: S1: Grind corn germ meal into 100-200 mesh, mix with water according to mass, and prepare corn germ meal solution; S2: adjusting the pH value of the corn germ meal solution to 6.5-7.5, adding a composite protease, and performing enzymatic hydrolysis at 45-50° C. for 50-90 minutes to obtain an enzymatic hydrolyzate A; S3: adjusting the pH value of the enzymatic hydrolysate A to 8.0-9.0, adding alkaline protease, performing enzymatic hydrolysis at 48-54° C. for 20-40 minutes, centrifuging, and collecting the supernatant to obtain enzymatic hydrolysate B; S4: filtering the enzymatic hydrolyzate B to obtain a filtrate and a filter cake, ultrafiltering the filtrate, and collecting the effluent; S5: spray-drying the effluent to obtain the corn germ meal extract.
2. The method for preparing a corn germ meal extract according to claim 1, wherein: In S1, the mass ratio of the crushed corn germ meal to water is 1:(10-20).
3. The method for preparing a corn germ meal extract according to claim 1, wherein: In S2, the composite protease comprises cellulase and papain, the cellulase and papain are mixed in a ratio of 1:(1-5), and the added amount of the composite protease is 0.2-0.5% of the mass of the corn germ meal solution.
4. The method for preparing a corn germ meal extract according to claim 1, wherein: In S3, the amount of alkaline protease added is 0.3-0.7% of the mass of the enzymatic solution A.
5. The method for preparing a corn germ meal extract according to claim 1, wherein: In S4, the mesh number of the filter cloth for the pressure filtration is 150-250 mesh, and the molecular weight cut-off of the ultrafiltration is 5000-8000 Da.
6. The method for preparing a corn germ meal extract according to claim 1, wherein: In S5, the air inlet temperature of the spray drying is 200-240°C, and the air outlet temperature is 70-90°C.
7. An application of a corn germ meal extract, characterized in that: The corn germ meal extract is used to improve the heat stress resistance, reproductive performance and growth performance of rabbits in a heat stress environment. The corn germ meal extract is obtained by the preparation method described in any one of claims 1 to 6.