High-protein-content soybean meal for aquatic products as well as production process and application thereof

Abstract

According to the high-protein-content soybean meal for the aquatic products and the production technology and application of the high-protein-content soybean meal for the aquatic products, a yeast-lactic acid bacteria two-step fermentation technology is adopted, technological conditions are optimized, the high-protein-content soybean meal is produced, the soybean meal does not contain carbohydrates and anti-nutritional factors which are unfavorable for growth of aquatic animals, and the production performance is improved; meanwhile, a large amount of fish meal can be replaced, the contradiction between the shortage of fish meal resources and the dramatic increase of fish meal demands is solved, and good economic benefits, social benefits and ecological benefits are obtained; a new thought and technical support are provided for the source and processing of the aquatic animal protein feed, and the method has a good application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of bioengineering, and in particular relates to a soybean meal with high protein content for aquaculture and a production process and application thereof. Background Art

[0002] Aquatic animals have higher requirements for protein content in feed, which is generally 2-4 times or even more than that of livestock and poultry. The source of protein feed for aquatic animals mainly depends on fish meal. Fish meal is a high-quality protein source, and its main nutritional characteristics are high protein content, amino acids, and complete and balanced composition. With the development of aquaculture and the breeding of various special aquatic animals, the demand for aquatic feed is increasing. The ensuing problem is the rising price of fish meal and the shortage of total amount. It will be difficult to meet the demand for fish meal in the development of the aquaculture industry by relying solely on fish meal. This has prompted people to replace fish meal with other protein sources that are cheap and abundant in source to meet the protein demand of aquatic animals in feed. Soybean meal is the best choice because of its high protein content, the ratio of amino acids in protein is similar to that of fish demand, the price is suitable, and the supply is sufficient. However, soy protein also contains trypsin inhibitors, oligosaccharides, phytic acid and calcium magnesium phytate, and factors that affect palatability, which affect the direct utilization of soy protein.

[0003] There are many defects in using soybean meal to directly replace fish meal, and it can only be a partial replacement. The main defects are: ① Low protein content. Generally, the protein content of peeled soybean meal is only about 48%, while the protein content of fish meal is more than 60%, and defatted fish meal is even higher. If soybean meal is used directly, it is necessary to add soybean meal to meet the protein content requirements, which will seriously squeeze the formula space of other raw materials. ② Soybean meal contains a certain amount of substances that are not conducive to fish growth, such as raffinose, stachyose, and anti-nutritional factors such as urease and protease inhibitors. The presence of these substances reduces the production performance of aquatic animals.

[0004] Therefore, in production, it is urgently necessary to develop a process for producing soybean meal preparation products, increase the protein content of soybean meal, remove sugars and anti-nutritional factors in soybean meal, so that it can replace fish meal in large quantities, solve the contradiction between the shortage of fish meal resources and the sharp increase in fish meal demand, and obtain good economic, social and ecological benefits. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a soybean meal with high protein content for aquatic products and a production process and application thereof. The two-step fermentation process of yeast and lactic acid bacteria is adopted to optimize the process conditions, and a soybean meal with high protein content is produced. The soybean meal does not contain sugar substances and anti-nutritional factors that are detrimental to the growth of aquatic animals, thereby improving the production performance. At the same time, the soybean meal can replace fish meal in large quantities, thereby solving the contradiction between the shortage of fish meal resources and the sharp increase in fish meal demand, and will obtain good economic benefits, social benefits and ecological benefits.

[0006] In order to achieve the above object, the present invention adopts the following scheme:

[0007] On the one hand, the present invention provides a production process of high-protein soybean meal for aquaculture, wherein the production process comprises a two-step fermentation process of yeast and lactic acid bacteria, wherein the first step is yeast fermentation and the second step is lactic acid bacteria fermentation.

[0008] The high-protein soybean meal produced by the production process provided by the present invention not only removes the sugar substances and anti-nutritional factors that are unfavorable to the growth of aquatic animals, but also significantly increases the protein content of the soybean meal, which can replace fish meal in large quantities and reduce production costs. At the same time, in some embodiments, the microbial fermentation sequence of the process is screened, and it is known that when the sequence of active dry yeast first fermentation and plant lactobacillus later fermentation is adopted, the protein content of the prepared soybean meal is the highest, reaching 62.3%.

[0009] Preferably, the yeast is active dry yeast, and the lactic acid bacteria is Lactobacillus plantarum.

[0010] In some embodiments, yeast and lactic acid bacteria were screened in combination, and it was found that when the yeast was preferably active dry yeast and the lactic acid bacteria was preferably Lactobacillus plantarum, the soybean meal protein content was the highest, reaching 62.3%, and raffinose and stachyose were completely removed.

[0011] Furthermore, in the active dry yeast liquid fermentation, the ratio of dehulled soybean meal to water is 25-35:100 by weight.

[0012] In some embodiments, the present invention screens the ratio of peeled soybean meal and water, and compared with the protein content of general soybean meal, it is found that when the weight ratio of peeled soybean meal and water is in the range of 25 to 35:100, the protein content of the soybean meal of the present invention is significantly improved, and the contents of raffinose and stachyose are significantly reduced.

[0013] Furthermore, in the active dry yeast liquid fermentation, the insulation time is 14 to 20 hours.

[0014] In some embodiments, the present invention screens the insulation time in the active dry yeast liquid fermentation step, and compared with the protein content of general soybean meal, it is found that when the insulation time is in the range of 14 to 20 hours, the protein content of the soybean meal of the present invention is significantly improved, and the contents of raffinose and stachyose are significantly reduced.

[0015] Furthermore, in the active dry yeast liquid fermentation, the amount of active dry yeast added is 100g to 200g of active dry yeast per 100kg of soybean meal.

[0016] In some embodiments, the present invention screens the amount of active dry yeast added in the active dry yeast liquid fermentation step, and compared with the protein content of general soybean meal, it is found that when the amount of active dry yeast added is 100g to 200g of active dry yeast per 100kg of soybean meal, the protein content of the soybean meal of the present invention is significantly improved, and the contents of raffinose and stachyose are significantly reduced.

[0017] Furthermore, in the Lactobacillus plantarum fermentation, the added amount of Lactobacillus plantarum is 0.01 to 0.03% of the weight of the soybean meal.

[0018] In some embodiments, the present invention screens the amount of Lactobacillus plantarum added in the Lactobacillus plantarum fermentation step, and compared with the protein content of general soybean meal, it is found that when the amount of Lactobacillus plantarum added is 0.01-0.03% of the weight of the soybean meal, the protein content of the soybean meal of the present invention is significantly improved, and the contents of raffinose and stachyose are significantly reduced.

[0019] Furthermore, in the Lactobacillus plantarum fermentation, the insulation time is 20 to 28 hours.

[0020] In some embodiments, the present invention screens the insulation time in the Lactobacillus plantarum fermentation step, and compared with the protein content of general soybean meal, it is found that when the insulation time is in the range of 20 to 28 hours, the protein content of the soybean meal of the present invention is significantly improved, and the contents of raffinose and stachyose are significantly reduced.

[0021] Preferably, in the active dry yeast liquid fermentation, the weight ratio of peeled soybean meal to water is 25:100; the insulation time is 14 hours, and the amount of active dry yeast added is 200g of active dry yeast per 100kg of soybean meal; in the Lactobacillus plantarum fermentation, the amount of Lactobacillus plantarum added is 0.01% of the weight of the soybean meal, and the insulation time is 28 hours.

[0022] In some embodiments, it can be seen that in active dry yeast liquid fermentation, when the ratio of peeled soybean meal to water is 25:100, the insulation time is 14 hours, and the amount of active dry yeast added is 200g of active dry yeast per 100kg of soybean meal; in Lactobacillus plantarum fermentation, when the amount of Lactobacillus plantarum added is 0.01% of the weight of the soybean meal and the insulation time is 28 hours, the soybean meal produced by the present invention has the highest protein content, which can reach 62.3%, and raffinose and stachyose have been completely removed.

[0023] On the other hand, the present invention provides the use of two microorganisms for synergistic fermentation to prepare a preparation for increasing the protein content in soybean meal, or a preparation for removing sugar substances and anti-nutritional factors in soybean meal, wherein the microorganisms include active dry yeast and Lactobacillus plantarum; the order of the synergistic fermentation is the first step of active dry yeast liquid fermentation and the second step of Lactobacillus plantarum fermentation.

[0024] In another aspect, the present invention provides a high-protein soybean meal for aquaculture, wherein the soybean meal is produced by the production process described in any one of the above technical solutions.

[0025] The beneficial effects of the present invention are:

[0026] 1. The present invention provides a two-step fermentation process of yeast and lactic acid bacteria, which determines the process conditions so that soybean meal exists in the form of being soaked in an aqueous solution, various sugar substances are effectively soaked out, and active dry yeast effectively converts glucose and sucrose in the soybean meal into carbon dioxide for direct elimination; plant lactobacillus fermentation effectively removes oligosaccharide anti-nutritional factors such as raffinose, stachyose and verbascose, as well as urease and protease inhibitors, etc., produces soluble lactic acid, efficiently removes substances that are detrimental to fish growth, and improves the production performance of aquatic animals.

[0027] 2. In the production process of the present invention, under the action of active dry yeast and Lactobacillus plantarum, the pH value of the slurry is between 4.0 and 4.5, near the isoelectric point of soybean protein, which can effectively reduce the solubility of soybean protein, facilitate solid-liquid separation and reduce protein loss, and significantly increase the protein content in soybean meal to 62.3%.

[0028] 3. The product obtained after processing in the present invention has a fermented aroma and moderate sourness, which is beneficial to the taste of farmed fish, increases palatability, and improves the feed intake of aquatic animals.

[0029] 4. The processed high-protein soybean meal provided by the present invention is low-priced and abundant in source, and can replace fish meal in large quantities, thus resolving the contradiction between the shortage of fish meal resources and the sharp increase in fish meal demand, and will achieve good economic, social and ecological benefits.

[0030] 5. The high-protein soybean meal and its production process provided by the present invention provide new ideas and technical support for the source and processing of aquatic animal protein feed, and have good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the examples. It should be pointed out that the examples described below are intended to facilitate the understanding of the present invention and do not have any limiting effect on the present invention.

[0032] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0033] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0034] The plant lactobacillus powder and active dry yeast used in the present invention are commercially available food additives, and the public can also obtain them through other public channels. Since they do not belong to the innovative content of the present invention, they will not be introduced in detail.

[0035] In the present invention, it is known that the protein content of soybean meal on the market is generally between 43% and 48%, the protein content of soybean meal containing whole soybean hulls is generally about 43%, and the protein content of completely dehulled soybean meal is about 48%. The fermentation production of high protein generally uses dehulled soybean meal containing about 48% protein.

[0036] Example 1 A production process of high-protein soybean meal for aquaculture

[0037] The production process provided in this embodiment is the best process, and the steps are as follows:

[0038] (1) Active dry yeast liquid fermentation treatment: Peeled soybean meal and water are added to a heat-insulated storage tank at a weight ratio of 25:100, and hot water is added for mixing. The activated active dry yeast is added while the water is added for mixing. The temperature of the water and soybean meal mixture is kept at 30-33°C, and then kept warm for 14 hours. The amount of active dry yeast added is 200g of active dry yeast per 100kg of soybean meal. In order to speed up the fermentation of the yeast, the active dry yeast is activated in advance by dissolving it with a small amount of warm water at 30-33°C and keeping it warm for 0.5h-1h.

[0039] (2) Fermentation of plant lactobacillus: plant lactobacillus powder is directly introduced into a heat-insulating storage tank, and is connected to the material treated in step (1) in an amount of 0.01% of the weight of soybean meal, and heated to keep the temperature of the soybean meal and water mixture at 35-37° C. The appropriate temperature can accelerate the growth and fermentation of lactic acid bacteria. After 28 hours of heat preservation, the culture is terminated. After the culture is completed, the protein in the soybean meal is basically in an insoluble precipitation state, and then the solid-liquid separation is carried out by screw extrusion, and the solid bundle is dried and dried. The protein content is measured to be 62.3%.

[0040] In this embodiment, in step (1), the active dry yeast is commercially available and meets the standards for food additives; in step (2), the Lactobacillus plantarum powder is commercially available and meets the standards for food additives.

[0041] In this embodiment, a two-step fermentation process of yeast-lactic acid bacteria is adopted, so that the soybean meal exists in the form of being soaked in an aqueous solution, and various sugar substances are effectively soaked out; at the same time, the yeast can effectively convert the glucose and sucrose in the soybean meal into carbon dioxide, which is directly removed, and the plant lactobacillus fermentation can effectively remove oligosaccharide anti-nutritional factors such as raffinose, stachyose and verbascose, and produce soluble lactic acid. Under the action of yeast and plant lactobacillus, the pH value of the slurry is between 4.0 and 4.5, near the isoelectric point of soy protein, which can effectively reduce the solubility of soy protein, facilitate solid-liquid separation and reduce protein loss. The dried product has a fermented aroma and a moderate sour taste, which is beneficial to the taste of farmed fish and increases feed intake.

[0042] Therefore, it can be seen that the production process provided in this embodiment is the best process. Compared with general soybean meal, the protein content of the produced soybean meal is significantly increased, reaching 62.3%.

[0043] Example 2 A production process of high-protein soybean meal for aquaculture (different conditions)

[0044] This embodiment provides a production process under different conditions, and the steps are as follows:

[0045] (1) Active dry yeast liquid fermentation treatment: Peeled soybean meal and water are added to a heat-insulated storage tank at a weight ratio of 30:100, and hot water is added to mix. The activated active dry yeast is added while adding water and mixing. The temperature of the water and soybean meal mixture is kept at 30-33°C, and then kept warm for 17 hours. The amount of active dry yeast added is 150g of active dry yeast per 100kg of soybean meal. In order to speed up the fermentation of yeast, the active dry yeast is activated in advance by dissolving it with a small amount of warm water at 30-33°C and keeping it warm for 0.5h-1h.

[0046] (2) Fermentation of plant lactobacillus: plant lactobacillus powder is directly introduced into a heat-insulating storage tank, and is connected to the material treated in step (1) in an amount of 0.02% of the weight of soybean meal, and heated to keep the temperature of the soybean meal and water mixture at 35-37° C. The appropriate temperature can accelerate the growth and fermentation of lactic acid bacteria. After 24 hours of heat preservation, the culture is terminated. After the culture is completed, the protein in the soybean meal is basically in an insoluble precipitation state, and then the solid-liquid separation is carried out by screw extrusion, and the solid bundle is dried and dried. The protein content is determined to be 61.2%.

[0047] The remaining steps are the same as in Example 1.

[0048] In this embodiment, the two-step fermentation process of yeast-lactic acid bacteria is still adopted, but the process conditions are changed. It is found that when the weight ratio of peeled soybean meal and water, the insulation time, the addition amount of active dry yeast, and the addition amount of plant lactobacillus are changed, the protein content of the soybean meal finally produced is 61.2%. Compared with the optimal process conditions, the protein content has decreased, but compared with the general soybean meal, the protein content is still significantly improved. Therefore, it can be seen that the process conditions provided in this embodiment can also significantly increase the protein content of soybean meal, but the production process and the optimal process conditions in the preferred embodiment 1 can produce the highest protein content of soybean meal.

[0049] Example 3 A production process of high-protein soybean meal for aquaculture (different conditions)

[0050] This embodiment provides a production process under different conditions, and the steps are as follows:

[0051] (1) Active dry yeast liquid fermentation treatment: Peeled soybean meal and water are added to a heat-insulated storage tank at a weight ratio of 35:100, and hot water is added to mix. The activated active dry yeast is added while the water is added. The temperature of the water and soybean meal mixture is kept at 30-33°C, and then kept warm for 20 hours. The amount of active dry yeast added is 100g of active dry yeast per 100kg of soybean meal. In order to speed up the fermentation of yeast, the active dry yeast is activated in advance by dissolving it with a small amount of warm water at 30-33°C and keeping it warm for 0.5h-1h.

[0052] (2) Fermentation of plant lactobacillus: plant lactobacillus powder is directly introduced into a heat-insulating storage tank, and is connected to the material treated in step (1) in an amount of 0.03% of the weight of soybean meal, and heated to keep the temperature of the soybean meal and water mixture at 35-37° C. The appropriate temperature can accelerate the growth and fermentation of lactic acid bacteria. After 20 hours of heat preservation, the culture is terminated. After the culture is completed, the protein in the soybean meal is basically in an insoluble precipitation state, and then the solid-liquid separation is carried out by screw extrusion, and the solid bundle is dried and dried. The protein content is measured to be 60.6%.

[0053] The remaining steps are the same as in Example 1.

[0054] In this embodiment, the two-step fermentation process of yeast-lactic acid bacteria is still used, but the process conditions are changed. It is found that when the weight ratio of peeled soybean meal and water, the insulation time, the addition amount of active dry yeast, and the addition amount of plant lactobacillus continue to change, the protein content of the soybean meal finally produced is 60.6%. Compared with the optimal process conditions, the protein content has decreased, but compared with the general soybean meal, the protein content is still significantly improved. Therefore, it can be further known that the process conditions provided in this embodiment can also significantly increase the protein content of soybean meal, but the production process and the optimal process conditions in the preferred embodiment 1 can produce the highest protein content of soybean meal.

[0055] Example 4 Screening of fermentation strains

[0056] In order to obtain the best effect in Example 1, this example performs combined screening on yeast and lactic acid bacteria respectively, and there are several ways (the other unmentioned operation processes and conditions are all the best conditions in Example 1, which are the same; because in the experimental process, anti-nutritional factors are generally completely removed by filtration after lactic acid bacteria fermentation, so in this example, the effect is judged according to the content of soybean meal protein and the content of two oligosaccharides, raffinose and stachyose):

[0057] 1. Yeast: active dry yeast; Lactic acid bacteria: Lactobacillus plantarum;

[0058] 2. Yeast: active dry yeast; lactic acid bacteria: Lactobacillus acidophilus;

[0059] 3. Yeast: active dry yeast; lactic acid bacteria: Lactobacillus casei;

[0060] 4. Yeast: Candida utilis; Lactic acid bacteria: Lactobacillus plantarum;

[0061] 5. Yeast: Candida utilis; Lactic acid bacteria: Lactobacillus acidophilus;

[0062] 6. Yeast: Candida utilis; Lactic acid bacteria: Lactobacillus casei;

[0063] 7. Yeast: Saccharomyces boulardii; Lactic acid bacteria: Lactobacillus plantarum;

[0064] 8. Yeast: Saccharomyces boulardii; Lactic acid bacteria: Lactobacillus acidophilus;

[0065] 9. Yeast: Saccharomyces boulardii; Lactic acid bacteria: Lactobacillus casei;

[0066] 10. General soybean meal: not processed by the process of the present invention

[0067] The specific results are shown in Table 1:

[0068] Table 1 Effects of different fermentation processes on the content of protein, raffinose and stachyose in soybean meal

[0069] Combination Soybean meal protein content Raffinose content Stachyose content 1 62.3％ 0％ 0％ 2 58.2％ 0.5％ 0.60％ 3 56.8％ 0.4％ 0.51％ 4 59.3％ 0.2％ 0.41％ 5 57.2％ 0.4％ 0.54％ 6 56.5％ 0.5％ 0.63％ 7 58.8％ 0.6％ 0.48％ 8 56.1％ 0.9％ 0.56％ 9 55.7％ 1.1％ 0.64％ 10 48.2％ 5.37％ 4.12％

[0070] As can be seen from Table 1, compared with general soybean meal that has not been processed by the process of the present invention, the soybean meal produced by the yeast-lactic acid bacteria two-step fermentation process adopted by the present invention has a significantly increased protein content, while the raffinose and stachyose contents are significantly reduced; and when the preferred yeast is active dry yeast and the lactic acid bacteria is Lactobacillus plantarum, the soybean meal protein content is the highest, reaching 62.3%, and raffinose and stachyose are completely removed; at the same time, compared with active dry yeast, the other two yeasts provided in this embodiment are too expensive, which is not conducive to the commercial production of the product.

[0071] Meanwhile, in the present embodiment, the lactic acid bacteria (Lactobacillus plantarum) is fully used in production and is tested. The experimental results show that the soybean meal protein content prepared by fully using Lactobacillus plantarum fermentation is slightly lower than that of yeast as active dry yeast and lactic acid bacteria as Lactobacillus plantarum, but the protein product acidity fermented is too high, which is unsuitable for some aquatic animals, thereby reducing their feed intake. In the present embodiment, first yeast is used to fully utilize glucose and sucrose, and carbon dioxide is removed, and then lactic acid bacteria is used to utilize oligosaccharides such as raffinose and stachyose that yeast in soybean meal cannot utilize, so that the method produces less acid, and the pH of the fermented liquid is between 4.0 and 4.5, i.e. near the point of soybean meal protein, which significantly reduces the dissolution of protein and reduces loss.

[0072] Therefore, the present invention determines the fermentation process. When a yeast-lactic acid bacteria two-step fermentation process is adopted, and preferably the yeast is active dry yeast and the lactic acid bacteria is Lactobacillus plantarum, the prepared soybean meal has the highest protein content, and sugar substances and anti-nutritional factors are completely removed.

[0073] Example 5 Fermentation process and sequence screening

[0074] In order to obtain the best effect in Example 1, this example screened yeast-lactic acid bacteria simultaneous fermentation and two-step fermentation processes in the following ways (the remaining operating processes and conditions not mentioned are all the best conditions in Example 1, which are the same; because in the experimental process, anti-nutritional factors are generally completely removed by lactic acid bacteria fermentation and then screw extrusion solid-liquid separation treatment, so in this example, the effect is judged according to the content of soybean meal protein and the content of two oligosaccharides, raffinose and stachyose):

[0075] 1. A two-step fermentation process is used: (1) active dry yeast liquid fermentation; (2) Lactobacillus plantarum fermentation;

[0076] 2. Use active dry yeast and Lactobacillus plantarum for simultaneous fermentation;

[0077] 3. A two-step fermentation process is used: the fermentation sequence is (1) Lactobacillus plantarum fermentation; (2) active dry yeast liquid fermentation;

[0078] 4. General soybean meal: not processed by the process of the present invention.

[0079] The specific results are shown in Table 2:

[0080] Table 2 Effects of different fermentation processes and sequences on the content of protein, raffinose and stachyose in soybean meal

[0081]

[0082] As can be seen from Table 2, compared with the yeast-lactic acid bacteria two-step fermentation process (method 1) adopted in the present invention, the soybean meal obtained by simultaneous fermentation in method 2 has: 1) a decreased protein content, while the contents of raffinose and stachyose are still relatively high, and the removal is not obvious; 2) when simultaneous fermentation is adopted in method 2, on the one hand, because the fermentation temperature of plant lactobacillus is 30-37°C, while active dry yeast works at 28-33°C and basically does not work above 35°C; on the other hand, plant lactobacillus produces more acid after fermentation, and the effect of active dry yeast will also be inhibited under high acidity. Therefore, when plant lactobacillus (lactic acid bacteria) exists, active dry yeast (yeast) generally has basically lost its effect, that is, it has basically become plant lactobacillus (lactic acid bacteria) fermented alone. In this case, the acidity of the fermented protein product is too high, which is not suitable for feeding some aquatic animals.

[0083] When method 3 is used, the situation is similar to that of simultaneous fermentation in method 2. On the one hand, the protein content of the produced soybean meal decreases, while the contents of raffinose and stachyose are still high, and the removal is not obvious; on the other hand, when Lactobacillus plantarum is fermented first, excessive acid production will still inhibit the action of active dry yeast, and the acidity of the fermented protein product is too high, which is not suitable for some aquatic animals.

[0084] Therefore, the present invention determines the fermentation process and sequence. When the yeast-lactic acid bacteria two-step fermentation process is preferably adopted, and the fermentation sequence is (1) active dry yeast liquid fermentation; (2) plant lactobacillus fermentation, the prepared soybean meal has the highest protein content, reaching 62.3%, and sugar substances and anti-nutritional factors are completely removed, while the acid production is low, thereby improving the adaptability and palatability of the product, thereby increasing the feed intake of farmed fish.

[0085] Example 6 Screening of different ratios of dehulled soybean meal and water

[0086] In order to obtain the best effect in Example 1, the ratio of peeled soybean meal and water was screened in the following ways (the other operating processes and conditions not mentioned are the best conditions in Example 1, which are the same; because in the experimental process, anti-nutritional factors are generally completely removed by lactic acid bacteria fermentation and then filtration treatment, so in this embodiment, the effect is judged according to the content of soybean meal protein and the content of two oligosaccharides, raffinose and stachyose):

[0087] 1. The weight ratio is dehulled soybean meal: water = 25:100;

[0088] 2. The weight ratio is dehulled soybean meal: water = 30:100;

[0089] 3. The weight ratio is dehulled soybean meal: water = 35:100;

[0090] 4. General soybean meal: not processed by the process of the present invention.

[0091] The specific results are shown in Table 3:

[0092] Table 3 Protein, raffinose and stachyose contents of soybean meal in different weight ratios of dehulled soybean meal and water

[0093]

[0094] As can be seen from Table 3, compared with the optimal conditions in Example 1 (the weight ratio of the optimal conditions is 25:100), when only the weight ratio of dehulled soybean meal and water is changed, 1) the protein content of soybean meal decreases, but compared with the protein content of general soybean meal, it is still significantly improved; 2) the content of raffinose and stachyose in soybean meal is significantly lower than that of general soybean meal, but it is not completely removed. This is because within a certain range of proportions, the higher the moisture, the better the effect, that is, the higher the protein content of soybean meal, but the volume of the fermentation tank is constant, when the water consumption increases, the output will decrease accordingly, thereby increasing the cost.

[0095] Therefore, in this embodiment, after the ratio screening test, the weight ratio range of the dehulled soybean meal and water is determined. When the weight ratio of the dehulled soybean meal and water is 25 to 35:100, the protein content of the soybean meal can be significantly increased, and the content of raffinose and stachyose can be reduced. When the ratio of the dehulled soybean meal is increased, the protein content of the soybean meal will be significantly reduced, and the content of raffinose and stachyose will also be significantly increased accordingly; and when the proportion of water continues to increase, the output of the dehulled soybean meal produced in the end will be significantly reduced, which greatly increases the cost. At the same time, it was found through screening in this embodiment that when the weight ratio of the dehulled soybean meal and water was 25:100, the protein content of the soybean meal produced was the highest, reaching 62.3%, and raffinose and stachyose were completely removed.

[0096] It can be seen from this that the preferred weight ratio of dehulled soybean meal to water is 25-35:100, and the effect is best when the weight ratio of dehulled soybean meal to water is 25:100.

[0097] Screening of different holding times in step (1) of Example 7

[0098] In order to obtain the best effect in Example 1, the present embodiment screened different holding times in step (1) in the following ways (the other operating processes and conditions not mentioned are the best conditions in Example 1 and are the same; in the experimental process, anti-nutritional factors are generally completely removed by solid-liquid separation after lactic acid bacteria fermentation. Therefore, in the present embodiment, the effect is judged according to the content of soybean meal protein and the content of two oligosaccharides, raffinose and stachyose):

[0099] 1. The holding time in step (1) is 14 h;

[0100] 2. The holding time in step (1) is 17 h;

[0101] 3. The holding time in step (1) is 20 hours;

[0102] 4. General soybean meal: not processed by the process of the present invention.

[0103] The specific results are shown in Table 4:

[0104] Table 4 Effect of different holding time in step (1) on the protein and raffinose content of soybean meal

[0105]

[0106] It can be seen from Table 4 that, compared with the optimal conditions in Example 1, when only the insulation time in step (1) is changed, 1) the protein content of soybean meal decreases, but is still significantly improved compared with the protein content of general soybean meal; 2) the raffinose in soybean meal is significantly reduced compared with general soybean meal, but is not completely removed.

[0107] At the same time, in this embodiment, experiments were also carried out under other insulation times. The experimental results showed that before reaching a certain insulation time of 14 hours, the longer the insulation time, the better the effect, that is, the more significant the increase in soybean meal protein content, the more significant the decrease in raffinose content, and when it reached 14 hours, the effect of extending the insulation time was not significantly improved.

[0108] The reason why the stachyose content was almost completely removed at different insulation times was that only raffinose was used in the active dry yeast fermentation process. Therefore, the change in insulation time had a more significant effect on the change in raffinose content. In the later Lactobacillus plantarum fermentation process, the conditions were optimal and raffinose and stachyose were further used. Therefore, the stachyose content was basically completely removed in the end.

[0109] Therefore, the present invention determines the range of the insulation time in step (1). When the insulation time is 14 to 20 hours, the protein content of the soybean meal can be significantly increased and the content of raffinose can be reduced. When the optimal insulation time in step (1) is 14 hours, the protein content of the prepared soybean meal is the highest, reaching 62.3%, and the raffinose has been completely removed.

[0110] Example 8 Screening of the amount of active dry yeast added

[0111] In order to obtain the best effect in Example 1, this example screened different active dry yeast addition amounts in step (1) in the following ways (the other operating processes and conditions not mentioned are the best conditions in Example 1 and are the same; in the experimental process, anti-nutritional factors can be completely removed by lactic acid bacteria fermentation and then screw extrusion solid-liquid separation. Therefore, in this example, the effect is judged according to the content of soybean meal protein and the content of two oligosaccharides, raffinose and stachyose):

[0112] 1. The amount of active dry yeast added is 200g of active dry yeast per 100kg of soybean meal;

[0113] 2. The amount of active dry yeast added is 150g of active dry yeast per 100kg of soybean meal;

[0114] 3. The amount of active dry yeast added is 100g of active dry yeast per 100kg of soybean meal;

[0115] 4. General soybean meal: not processed by the process of the present invention.

[0116] The specific results are shown in Table 5:

[0117] Table 5 Effect of different active dry yeast addition amounts on soybean meal protein and raffinose content

[0118]

[0119] As can be seen from Table 5, compared with the optimal conditions in Example 1, when only the amount of active dry yeast added was changed, 1) the protein content of soybean meal decreased, but compared with the protein content of general soybean meal, it was still significantly improved; 2) the raffinose content in soybean meal was significantly reduced compared with general soybean meal, but was not completely removed.

[0120] The reason why the stachyose content was almost completely removed at different insulation times was that only raffinose was used in the active dry yeast fermentation process. Therefore, the change in the amount of active dry yeast added had a more significant effect on the change in the raffinose content. In the later Lactobacillus plantarum fermentation process, the conditions were optimal and raffinose and stachyose were further used. Therefore, the stachyose content was basically completely removed in the end.

[0121] Therefore, the present invention determines the range of the amount of active dry yeast added in step (1). When the amount of active dry yeast added is 100g to 200g per 100kg of soybean meal, the protein content of the soybean meal can be significantly increased and the content of raffinose can be reduced. When the amount of active dry yeast added is 200g per 100kg of soybean meal, the protein content of the prepared soybean meal is the highest, reaching 62.3%, and the raffinose has been completely removed.

[0122] Example 9 Screening of the amount of Lactobacillus plantarum added

[0123] In order to obtain the best effect in Example 1, the addition amount of plant lactobacillus in step (2) was screened in the present embodiment in the following ways (the remaining unmentioned operating processes and conditions are the best conditions in Example 1, which are all the same; because in the experimental process, anti-nutritional factors are generally filtered and treated after lactic acid bacteria fermentation, and can be completely removed, so in the present embodiment, the effect is judged according to the content of soybean meal protein content, raffinose and stachyose oligosaccharides):

[0124] 1. The amount of Lactobacillus plantarum added is 0.01% of the weight of soybean meal;

[0125] 2. The amount of Lactobacillus plantarum added is 0.02% of the weight of soybean meal;

[0126] 3. The amount of Lactobacillus plantarum added is 0.03% of the weight of soybean meal;

[0127] 4. General soybean meal: not processed by the process of the present invention.

[0128] The specific results are shown in Table 6:

[0129] Table 6 Effect of different addition amounts of Lactobacillus plantarum on the content of protein, raffinose and stachyose in soybean meal

[0130]

[0131] As can be seen from Table 6, compared with the optimal conditions in Example 1, when only the addition amount of Lactobacillus plantarum was changed, the protein content of soybean meal decreased, but compared with the protein content of general soybean meal, it was still significantly improved.

[0132] When the addition amount of plant lactobacillus is 0.01%, 0.02% or 0.03%, the contents of raffinose and stachyose in the soybean meal are completely removed, which means that when the addition amount is 0.01% of the soybean meal weight, the effect of completely removing the two oligosaccharides can be achieved. Therefore, considering the cost comprehensively, the addition amount of plant lactobacillus is preferably 0.01% in the present embodiment.

[0133] Therefore, the present invention determines the range of the amount of Lactobacillus plantarum added in step (2). When the amount of Lactobacillus plantarum added is 0.01% to 0.03% of the weight of the soybean meal, the protein content of the soybean meal can be significantly increased, and the contents of raffinose and stachyose can be reduced. When the amount of Lactobacillus plantarum added is 0.01% of the weight of the soybean meal, the protein content of the prepared soybean meal is the highest, reaching 62.3%, and raffinose and stachyose are completely removed.

[0134] Screening of different holding times in step (2) of Example 10

[0135] In order to obtain the best effect in Example 1, the present embodiment screened different holding times in step (2) in the following ways (the rest of the operation processes and conditions not mentioned are the best conditions in Example 1 and are the same; in the experimental process, anti-nutritional factors are generally completely removed by lactic acid bacteria fermentation and then filtration treatment. Therefore, in the present embodiment, the effect is judged according to the content of soybean meal protein and the content of two oligosaccharides, raffinose and stachyose):

[0136] 1. The holding time in step (2) is 28 hours;

[0137] 2. The holding time in step (2) is 24 hours;

[0138] 3. The holding time in step (2) is 20 hours;

[0139] 4. General soybean meal: not processed by the process of the present invention.

[0140] The specific results are shown in Table 7:

[0141] Table 7 Effect of different holding time in step (2) on the content of soybean meal protein, raffinose and stachyose

[0142]

[0143] As can be seen from Table 7, compared with the optimal conditions in Example 1, when only the insulation time in step (2) is changed, 1) the protein content of soybean meal decreases, but is still significantly improved compared with the protein content of general soybean meal; 2) the content of raffinose and stachyose in soybean meal is significantly reduced compared with general soybean meal, but is not completely removed.

[0144] In this embodiment, screening of other different insulation times was also carried out, and it was found that within a certain range, at the beginning, as the insulation time was extended, the content of raffinose and stachyose decreased rapidly. When it decreased to a certain level, the rate slowed down. When it was further extended to 28 hours, raffinose and stachyose were completely removed.

[0145] Therefore, the present invention determines the insulation time in step (2). When the insulation time is 20 to 28 hours, the protein content of the soybean meal can be significantly increased, and the contents of raffinose and stachyose can be reduced. When the insulation time in step (2) is 28 hours, the protein content of the prepared soybean meal is the highest, reaching 62.3%, and raffinose and stachyose are completely removed.

[0146] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A production process of high-protein soybean meal for aquatic products, characterized in that: The production process includes a two-step yeast-lactic acid bacteria fermentation process, wherein the first step is yeast fermentation and the second step is lactic acid bacteria fermentation.

2. The production process according to claim 1, characterized in that: The yeast is active dry yeast, and the lactic acid bacteria is Lactobacillus plantarum.

3. The production process according to claim 2, characterized in that: In active dry yeast liquid fermentation, the ratio of dehulled soybean meal to water is 25-35:100 by weight.

4. The production process according to claim 3, characterized in that: In active dry yeast liquid fermentation, the insulation time is 14 to 20 hours.

5. The production process according to claim 4, characterized in that: In liquid fermentation with active dry yeast, the amount of active dry yeast added is 100g to 200g for every 100kg of soybean meal.

6. The production process according to claim 5, characterized in that: In the fermentation of Lactobacillus plantarum, the added amount of Lactobacillus plantarum is 0.01-0.03% of the weight of soybean meal.

7. The production process according to claim 6, characterized in that: In the fermentation of Lactobacillus plantarum, the insulation time is 20 to 28 hours.

8. The production process according to claim 7, characterized in that: In the active dry yeast liquid fermentation, the weight ratio of peeled soybean meal and water is 25:100, the insulation time is 14 hours, and the amount of active dry yeast added is 200g of active dry yeast per 100kg of soybean meal; in the plant lactobacillus fermentation, the amount of plant lactobacillus added is 0.01% of the weight of the soybean meal, and the insulation time is 28 hours.

9. Use of two microorganisms for synergistic fermentation to prepare a preparation for increasing the protein content in soybean meal, or a preparation for removing sugar substances and anti-nutritional factors in soybean meal, characterized in that: The microorganisms include active dry yeast and Lactobacillus plantarum; the order of the coordinated fermentation is that the first step is active dry yeast liquid fermentation, and the second step is Lactobacillus plantarum fermentation.

10. A high-protein soybean meal for aquaculture, characterized in that: The soybean meal is produced by the production process according to any one of claims 1 to 8.

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