Production method of cat litter bean dregs with high dietary fibers

Abstract

The invention discloses a production method of high-dietary-fiber cat litter bean dregs. The production method comprises the following steps: soaking soybeans in water and cleaning; the pretreated soybeans and water are mixed and ground into thick liquid, the obtained ground paste is subjected to high-speed centrifugation and then separated, and soybean milk and wet bean dregs are obtained; adding water into the obtained wet bean dregs and stirring; and sequentially carrying out filter pressing, crushing, steam explosion, airflow flash drying and dry crushing on the wet bean dregs which are stirred by adding water to obtain the high-dietary-fiber cat litter bean dregs. The bean dregs generated in the bean product processing process are subjected to high-value development and utilization, and the dried bean dregs for the cat litter, which are low in moisture content and protein content, high in dietary fiber content, easy to store and transport, safe, sanitary, good in water absorption, easy to loosen without caking, clean and sanitary, are prepared.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive utilization of food production by-products, in particular to a method for producing high-dietary fiber cat litter bean dregs. Background Art

[0002] Okara is the main by-product of soybean processing related industries. Since the moisture content of okara is as high as 80-85%, it is inconvenient to store and transport, and the shelf life is short. It needs to be handled anytime and anywhere, otherwise it is easy to spoil and pollute the environment. So far, the use of okara at home and abroad is still mainly limited to feed and fertilizer. Recently, the research on okara as a functional food base has gradually increased, but often due to the high production cost and the small amount of addition in food, otherwise it affects the taste of food and cannot be well applied in actual production. Therefore, the extraction and development and application of functional components in okara are currently only in the laboratory stage. For large-scale soy product companies, the amount of okara produced every day is huge, and the problem of comprehensive utilization is troubling the company. It is necessary to break through the food field and the traditional way of recycling okara, and open up new ways and solutions with large removal volume and good market prospects.

[0003] With the popularity of pet keeping and people paying more and more attention to environmental quality, how to better solve the environmental pollution problem caused by pet excrement during the breeding process, people not only put forward the requirements of water absorption and deodorization, but also the characteristics of non-toxicity, safety and easy care. Tofu cat litter is a new type of cat litter made from raw materials such as soybean dregs and corn flour. Because it is safe, non-toxic, degradable and can be flushed into the toilet, it has been favored by more and more cat owners. Making bean dregs into cat litter, through the research of high-value development and utilization of bean dregs produced in the process of soy product processing, improves the added value of bean dregs, which not only solves the problem of large-scale wet bean dregs treatment for enterprises, but also creates good economic income for enterprises, which has important and far-reaching significance for the green and sustainable development of the soybean processing industry.

[0004] Tofu cat litter is generally made from dry bean dregs. The traditional drying process of bean dregs consumes a lot of energy, and the dregs contain high content of sticky substances such as protein and polysaccharides, which makes them easy to clump and bake unevenly during baking. The resulting dry bean dregs have poor water absorption when used as cat litter raw materials. Summary of the invention

[0005] The invention aims to overcome the problems in the prior art that the bean dregs drying process has high energy consumption, the bean dregs have high contents of viscous substances such as proteins and polysaccharides, etc., which result in easy agglomeration and uneven baking during baking, and poor water absorption of the obtained dry bean dregs when used as cat litter raw materials. The invention provides a production method for high-dietary fiber cat litter bean dregs, and produces dry bean dregs for cat litter, which has low moisture content and protein content, high dietary fiber content, is easy to store and transport, is safe and hygienic, has good water absorption, is easy to loosen and not agglomerate, and is clean and hygienic.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A method for producing high-dietary fiber cat litter bean dregs comprises the following steps: (1) Raw material pretreatment: Soybeans are selected as raw materials, and the soybeans are soaked in water and washed to obtain pretreated soybeans; (2) grinding: mixing the pretreated soybeans with water for grinding, and subjecting the resulting ground paste to high-speed centrifugation to separate into soy milk and wet dregs; (3) Adding water and stirring: adding water to the obtained wet okara and stirring to remove sticky substances therein; (4) filtration and dehydration: the wet dregs after adding water and stirring are pumped into a filter press for filtration to obtain pressed dregs; (5) Crushing: crushing the pressed okara to disperse it into loose okara; (6) Steam explosion: steam explosion the crushed okara to obtain pre-dried okara; (7) airflow flash drying: subjecting the pre-dried bean dregs to airflow flash drying to obtain dried bean dregs; (8) Dry grinding: The dried bean dregs are dry ground to obtain high dietary fiber cat litter bean dregs with a moisture content of 10-13 wt %, a protein content of ≤11 wt %, a crude fiber content of ≤25 wt %, and a dietary fiber content of 68-75 wt %.

[0007] The present invention firstly uses soybean as raw material to prepare soy milk and its byproduct wet bean dregs through steps (1) and (2). The soy milk can be used for the production of soy products. The wet bean dregs are subsequently dried to obtain dry bean dregs that can be used as a raw material for cat litter. Before drying the wet bean dregs, the present invention firstly adds water, stirs and washes the bean dregs through step (3) to remove the slurry protein and sticky substances attached to the bean dregs that affect the baking effect, thereby changing the material properties of the bean dregs and avoiding uneven drying caused by agglomeration of the bean dregs in the subsequent drying process; then, through step (4), physical extrusion dehydration is adopted to remove about 20% of the water; and then, through step (6), the bean dregs are steam-exploded. During the steam-explosion process, high-pressure hot steam enters the bean dregs and penetrates into the gaps inside the fibers. When the high-pressure steam is released, the hot steam molecules that have penetrated into the fibers are instantly released from the relatively closed gaps in the form of airflow at high speed, so that the fibers are mechanically broken to a certain extent, the crude fiber content in the bean dregs is reduced, and components such as soluble dietary fiber in the cells can be released, so that the fluffiness and water absorption of the dried bean dregs can be significantly improved, which is beneficial to the application of the bean dregs in cat litter. After steam explosion, the dregs are uniformly dried by airflow flash evaporation, and after crushing, dry bean dregs for cat litter with low moisture and protein content, high dietary fiber content, easy storage and transportation, safe and hygienic, good water absorption, easy to loosen and not agglomerate, and clean and hygienic can be obtained. The present invention develops and utilizes the bean dregs produced in the process of bean product processing in a high-value manner, thereby increasing the added value of the bean dregs.

[0008] Preferably, the mass ratio of soybeans to water during soaking in step (1) is 1:3-5, and the soaking time is 8-15 hours.

[0009] Preferably, in step (2), the mass ratio of soybean to water during grinding is 1:4-5; the grinding is subjected to 2-3 cycles of high-speed centrifugation.

[0010] Preferably, in step (3), water is added and stirred at a mass ratio of water to wet bean dregs of 4 to 6:1, and the stirring time is 3 to 5 minutes.

[0011] Preferably, the pressure during the filtration in step (4) is 0.4 to 0.6 MPa, and the filtration time is 30 to 60 minutes.

[0012] Preferably, the steam pressure during steam explosion in step (6) is 0.5-1.0 MPa, and the pressure is maintained for 30-60 seconds. If the steam explosion intensity is too low, the mechanical breaking effect of the fiber is insufficient, and the soluble dietary fiber and other components in the cells cannot be fully released, and the fluffiness and water absorption of the bean dregs cannot be effectively improved; while if the steam explosion intensity is too high, the soluble reducing sugars formed by the degradation of hemicellulose during the steam explosion will react with the amino acids or proteins in the cells to undergo Maillard reaction, causing the bean dregs to brown, and in severe cases, carcinogens will be produced. The present invention can effectively improve the fluffiness and water absorption of the bean dregs while reducing the occurrence of browning reaction by controlling the steam explosion intensity.

[0013] Preferably, a protective agent is added to the bean dregs during steam explosion in step (6), wherein the protective agent is calcium alginate gel microspheres, and the preparation method thereof is as follows: dissolving sodium alginate in water to prepare a sodium alginate solution with a mass concentration of 1 to 2%; adding NaCl with a mass fraction of 0.5 to 1% to the sodium alginate solution, and stirring evenly to obtain a mixed solution; dripping the mixed solution drop by drop into a CaCl2 solution with a mass concentration of 2 to 3% with a syringe under stirring in a water bath, and continuing to stir in a water bath until gel is generated, the water bath temperature is 50 to 60° C., and the water bath stirring time is 20 to 40 min; washing the product and drying it to obtain the calcium alginate gel microspheres.

[0014] In order to protect the bean dregs from the Maillard reaction and browning during the steam explosion process, the present invention makes non-toxic calcium alginate gel microspheres by gelling sodium alginate and calcium ions. When the sodium alginate gel microspheres with a three-dimensional mesh structure are used as protective agents in the steam explosion of bean dregs, the gel microspheres swell and the gel structure is destroyed under the energy of the steam explosion. During the steam explosion process, water molecules will dissociate protons, and the acetyl groups on the hemicellulose will be hydrolyzed to produce acetic acid. Therefore, the steam explosion process is in a high-pressure hot acidic environment. After the gel structure of the calcium alginate gel microspheres is destroyed, free calcium ions and natural polysaccharide alginate are generated under the high-pressure hot acidic environment. Alginate can adhere to the surface of proteins released from cells to reduce the Maillard reaction between proteins and reducing sugars; at the same time, calcium ions can combine with amino acids to form inactive compounds, thereby inhibiting the combination between amino acids and carbonyl groups, and also inhibiting the occurrence of the Maillard reaction, so that the fluffiness and water absorption of the bean dregs during the steam explosion process can be effectively improved, and the Maillard reaction and browning will not occur. In addition, during the steam explosion process, alginic acid can also adhere to the cellulose surface after mechanical fracture, protecting cellulose, hemicellulose and other components from excessive degradation during the steam explosion process to generate products such as 5-hydroxymethylfurfural and formic acid, so as to adversely affect the subsequent application of bean dregs in cat litter. At the same time, when preparing calcium alginate gel microspheres, the present invention also adds NaCl as a small molecule pore-forming agent, forming more pores on the surface and inside of the gel microspheres, increasing its specific surface area, ensuring that the high-temperature steam can fully penetrate into the gel microspheres during the steam explosion process, thereby ensuring that the gel structure can be destroyed under the action of steam explosion, releasing calcium ions in a high-pressure hot acidic environment, and effectively inhibiting the occurrence of the Maillard reaction.

[0015] Preferably, the amount of the protective agent added is 1-5% of the mass of the dregs. If too little protective agent is added, the Maillard reaction during the gas explosion process cannot be effectively suppressed, and the dregs will brown; if too much protective agent is added, the fluffiness of the dregs will be affected, and the gel substance will easily cause the dregs to clump, affecting its drying effect and water absorption.

[0016] Preferably, in step (7), the air inlet temperature during airflow flash drying is ≥120°C, the air outlet temperature is ≤80°C, and the drying time is 2 to 4 hours.

[0017] Preferably, in step (8), the dried bean dregs are crushed to 50-80 mesh.

[0018] Therefore, the present invention has the following beneficial effects: (1) Before drying the wet dregs, the dregs are first stirred and cleaned with water to remove the slurry protein and sticky substances attached to the dregs that affect the baking effect, change the material properties of the dregs, and avoid agglomeration of the dregs in the subsequent drying process, resulting in uneven drying; (2) The wet bean dregs are dried by a method of filter pressing + steam explosion + airflow flash evaporation. Steam explosion can significantly improve the fluffiness and water absorption of the dried bean dregs, thereby obtaining dry bean dregs for cat litter with low moisture content and protein content, high dietary fiber content, good water absorption, easy to loosen and not clump, and clean and hygienic; (3) Adding protective agents during steam explosion can effectively prevent the Maillard reaction between proteins and amino acids in the cells and soluble reducing sugars, thereby preventing the dregs from browning or producing carcinogens. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with specific implementation methods.

[0020] In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in the industry. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art.

[0021] Overall embodiment: A method for producing high-dietary fiber cat litter bean dregs comprises the following steps: (1) Raw material pretreatment: select soybeans that are large, uniform, full, free of mold and impurities as raw materials, soak the soybeans in water, the mass ratio of soybeans to water is 1:3-5, and the soaking time is 8-15 hours; after the soaking is completed, drain the water in which the soybeans are soaked, and then wash the soybeans with clean water to obtain pretreated soybeans; (2) grinding: the pretreated soybeans and water are mixed in a mass ratio of 1:4-5 for grinding, and the resulting ground paste is subjected to 2-3 cycles of high-speed centrifugation to separate soy milk and wet dregs; (3) adding water and stirring: adding water to the obtained wet dregs at a mass ratio of water to wet dregs of 4 to 6:1 and stirring for 3 to 5 minutes; removing sticky substances therein; (4) filtration dehydration: the wet dregs after adding water and stirring are pumped into a filter press for filtration to obtain pressed dregs; the pressure during filtration is 0.4 to 0.6 MPa, and the filtration time is 30 to 60 minutes; (5) Crushing: crushing the pressed okara to disperse it into loose okara; (6) Steam explosion: steam-exploding the crushed dregs to obtain pre-dried dregs; the steam pressure during steam explosion is 0.5-1.0 MPa, and the pressure is maintained for 30-60 seconds; adding a protective agent of 1-5% of the mass of the dregs to the dregs during steam explosion, wherein the protective agent is calcium alginate gel microspheres, and the preparation method thereof is as follows: dissolving sodium alginate in water to prepare a sodium alginate solution with a mass concentration of 1-2%; adding 0.5-1% NaCl by mass to the sodium alginate solution, and stirring to obtain a mixed solution; dripping the mixed solution drop by drop into a CaCl2 solution with a mass concentration of 2-3% by using a syringe under stirring in a water bath, and continuing to stir in a water bath until gel is generated, the water bath temperature is 50-60° C., and the water bath stirring time is 20-40 minutes; washing the product and drying it to obtain the calcium alginate gel microspheres; (7) airflow flash drying: the pre-dried bean dregs are subjected to airflow flash drying to obtain dried bean dregs; the air inlet temperature during airflow flash drying is ≥120°C, the air outlet temperature is ≤80°C, and the drying time is 2 to 4 hours; (8) Dry grinding: The dried bean dregs are dry ground into 50-80 meshes to obtain high dietary fiber cat litter bean dregs with a moisture content of 10-13 wt %, a protein content of ≤11 wt %, a crude fiber content of ≤25 wt %, and a dietary fiber content of 68-75 wt %.

[0022] Embodiment 1: A method for producing high-dietary fiber cat litter bean dregs comprises the following steps: (1) Raw material pretreatment: large, uniform, full, mildew-free and impurity-free soybeans are selected as raw materials, and the soybeans are soaked in water, with a mass ratio of soybeans to water of 1:4, and the soaking time is 12 hours; after the soaking is completed, the water in which the soybeans are soaked is drained, and then the soybeans are washed with clean water to obtain pretreated soybeans; (2) grinding: the pretreated soybeans and water are mixed in a mass ratio of 1:4.5 for grinding, and the resulting ground paste is subjected to three cycles of high-speed centrifugation to separate soy milk and wet dregs; (3) Adding water and stirring: adding water to the obtained wet okara at a mass ratio of water to wet okara of 5:1 and stirring for 4 min; removing sticky substances therein; (4) filtration dehydration: the wet dregs after adding water and stirring are pumped into a filter press for filtration to obtain pressed dregs; the pressure during filtration is 50 MPa and the filtration time is 40 min; (5) Crushing: crushing the pressed okara to disperse it into loose okara; (6) Steam explosion: steam explosion the crushed dregs to obtain pre-dried dregs; the steam pressure during steam explosion is 0.8 MPa, and the pressure is maintained for 40 seconds; during steam explosion, a protective agent of 3% by weight of the dregs is added to the dregs, wherein the protective agent is calcium alginate gel microspheres, and the preparation method thereof is as follows: sodium alginate is dissolved in water to prepare a sodium alginate solution with a mass concentration of 1.5%; 0.8% by weight of NaCl is added to the sodium alginate solution, and the mixture is stirred to obtain a mixed solution; the mixed solution is dripped dropwise into a CaCl2 solution with a mass concentration of 2.5% by a syringe under stirring in a water bath, and the stirring in the water bath is continued until gel is generated, the water bath temperature is 55° C., and the stirring time in the water bath is 30 minutes; the product is washed and dried to obtain the calcium alginate gel microspheres; (7) airflow flash drying: the pre-dried bean dregs are subjected to airflow flash drying to obtain dried bean dregs; the air inlet temperature during airflow flash drying is 130° C., the air outlet temperature is 70° C., and the drying time is 3 h; (8) Dry grinding: The dried bean dregs are dry ground into 60 meshes to obtain high dietary fiber cat litter bean dregs.

[0023] Embodiment 2: A method for producing high-dietary fiber cat litter bean dregs comprises the following steps: (1) Raw material pretreatment: select soybeans that are large, uniform, full, free of mold and impurities as raw materials, soak the soybeans in water, the mass ratio of soybeans to water is 1:3, and the soaking time is 15 hours; after the soaking is completed, drain the water in which the soybeans are soaked, and then wash the soybeans with clean water to obtain pretreated soybeans; (2) grinding: the pretreated soybeans and water are mixed in a mass ratio of 1:4 for grinding, and the resulting ground paste is subjected to two cycles of high-speed centrifugation to separate soy milk and wet dregs; (3) Adding water and stirring: adding water to the obtained wet okara at a mass ratio of water to wet okara of 4:1 and stirring for 5 min; removing sticky substances therein; (4) filtration dehydration: the wet dregs after adding water and stirring are pumped into a filter press for filtration to obtain pressed dregs; the pressure during filtration is 0.4 and the filtration time is 60 min; (5) Crushing: crushing the pressed okara to disperse it into loose okara; (6) Steam explosion: steam explosion the crushed bean dregs to obtain pre-dried bean dregs; the steam pressure during steam explosion is 0.5 MPa, and the pressure is maintained for 60 seconds; during steam explosion, a protective agent of 1% by weight of the bean dregs is added to the bean dregs, wherein the protective agent is calcium alginate gel microspheres, and the preparation method thereof is as follows: sodium alginate is dissolved in water to prepare a sodium alginate solution with a mass concentration of 1%; 0.5% by weight of NaCl is added to the sodium alginate solution, and the mixture is stirred to obtain a mixed solution; the mixed solution is dripped dropwise into a CaCl2 solution with a mass concentration of 2% by using a syringe under stirring in a water bath, and the stirring in the water bath is continued until gel is generated, the water bath temperature is 50° C., and the stirring time in the water bath is 40 minutes; the product is washed and dried to obtain the calcium alginate gel microspheres; (7) airflow flash drying: the pre-dried bean dregs are subjected to airflow flash drying to obtain dried bean dregs; the air inlet temperature during airflow flash drying is 130° C., the air outlet temperature is 70° C., and the drying time is 3 h; (8) Dry grinding: The dried bean dregs are dry ground into 60 meshes to obtain high dietary fiber cat litter bean dregs.

[0024] Embodiment 3: A method for producing high-dietary fiber cat litter bean dregs comprises the following steps: (1) Raw material pretreatment: select soybeans that are large, uniform, full, free of mold and impurities as raw materials, soak the soybeans in water, the mass ratio of soybeans to water is 1:5, and the soaking time is 8 hours; after the soaking is completed, drain the water in which the soybeans are soaked, and then wash the soybeans with clean water to obtain pretreated soybeans; (2) grinding: the pretreated soybeans and water are mixed in a mass ratio of 1:5 for grinding, and the resulting ground paste is subjected to three cycles of high-speed centrifugation to separate soy milk and wet dregs; (3) Adding water and stirring: adding water to the obtained wet okara at a mass ratio of water to wet okara of 6:1 and stirring for 3 min; removing sticky substances therein; (4) filtration dehydration: the wet dregs after adding water and stirring are pumped into a filter press for filtration to obtain pressed dregs; the pressure during filtration is 0.6 MPa and the filtration time is 30 min; (5) Crushing: crushing the pressed okara to disperse it into loose okara; (6) Steam explosion: steam-exploding the crushed dregs to obtain pre-dried dregs; the steam pressure during steam explosion is 1.0 MPa, and the pressure is maintained for 30 seconds; adding a protective agent of 5% by mass of the dregs to the dregs during steam explosion, wherein the protective agent is calcium alginate gel microspheres, and the preparation method thereof is as follows: dissolving sodium alginate in water to prepare a sodium alginate solution with a mass concentration of 2%; adding 1% by mass of NaCl to the sodium alginate solution, and stirring evenly to obtain a mixed solution; dripping the mixed solution drop by drop into a CaCl2 solution with a mass concentration of 3% by using a syringe under stirring in a water bath, and continuing to stir in a water bath until gel is generated, the water bath temperature is 60° C., and the water bath stirring time is 20 minutes; washing the product and drying it to obtain the calcium alginate gel microspheres; (7) airflow flash drying: the pre-dried bean dregs are subjected to airflow flash drying to obtain dried bean dregs; the air inlet temperature during airflow flash drying is 130° C., the air outlet temperature is 70° C., and the drying time is 3 h; (8) Dry grinding: The dried bean dregs are dry ground into 60 meshes to obtain high dietary fiber cat litter bean dregs.

[0025] Comparative Example 1 (no water stirring before filter pressing): The difference between Comparative Example 1 and Example 1 is that the wet bean dregs obtained after refining are directly subjected to filter pressing and dehydration, and the step (3) of adding water and stirring is not performed. The remaining steps are the same as those in Example 1.

[0026] Comparative Example 2 (without steam explosion): The difference between Comparative Example 2 and Example 1 is that the steam explosion in step (6) is not performed, and the okara after filtering and crushing is directly subjected to air flow flash drying, and the remaining steps are the same as those in Example 1.

[0027] Comparative Example 3 (no protective agent added during steam explosion): The difference between Comparative Example 3 and Example 1 is that no protective agent is added during steam explosion, and the remaining steps are the same as those in Example 1.

[0028] Comparative Example 4 (NaCl is not added during the preparation of the protective agent): The difference between Comparative Example 4 and Example 1 is that the preparation method of the calcium alginate gel microsphere protective agent added during steam explosion is as follows: dissolving sodium alginate in water to prepare a sodium alginate solution with a mass concentration of 1.5%; using a syringe to dropwise add the sodium alginate solution into a CaCl2 solution with a mass concentration of 2.5% under stirring in a water bath, and continuing to stir in the water bath until gel is formed, the water bath temperature is 55°C, and the water bath stirring time is 30 minutes; the product is washed and dried to obtain the calcium alginate gel microspheres; the rest is the same as in Example 1.

[0029] The sensory properties and physicochemical properties of the cat litter okara prepared in the above examples and comparative examples were tested, and the results are shown in Table 1 and Table 2.

[0030] Table 1: Test results of sensory properties of cat litter dregs.

[0031] Table 2: Test results of physical and chemical properties of cat litter dregs.

[0032] As can be seen from Table 1 and Table 2, the bean dregs prepared by the method of the present invention in Examples 1 to 3 have a natural milky white color of soybeans, are loose and non-agglomerated, have no peculiar smell, are clean and hygienic; and have low moisture and protein contents, high dietary fiber content, and good water absorption, and are suitable for use as cat litter raw materials.

[0033] In Comparative Example 1, the wet bean dregs are not stirred with water before baking, and the slurry protein and sticky substances attached to the bean dregs cannot be effectively removed. The bean dregs are prone to agglomeration in the subsequent drying process, and the drying is uneven, resulting in high moisture content and protein content of the obtained dry bean dregs, and agglomeration, which is not conducive to use in high-quality cat litter.

[0034] In Comparative Example 2, the okara was not subjected to steam explosion, and the crude fiber content of the okara was high, and the dietary fiber content and water absorption rate were significantly lower than those in Example 1, which was not conducive to its application in cat litter. In Comparative Example 3, no protective agent was added during the steam explosion process, and the okara would brown and produce a burnt smell due to the occurrence of the Maillard reaction; in Comparative Example 4, no pore-forming agent NaCl was added during the preparation of the protective agent, and the high-temperature steam was difficult to fully penetrate into the gel microspheres during the steam explosion process, and the gel structure could not be effectively destroyed to release calcium ions in a high-pressure hot acidic environment, and the occurrence of the Maillard reaction could not be effectively inhibited. The okara would also brown and produce a burnt smell, which was not conducive to its use in cat litter.

[0035] The bean dregs for cat litter of the present invention are preferably made of soybeans as raw materials, and fresh bean dregs are obtained through selection, soaking, grinding and centrifugation, and are processed through water addition, stirring, cleaning, filter pressing, crushing, steam explosion, drying, pulverizing, packaging and other processes. The whole bean dregs processing process has low energy consumption and large processing capacity, and 10 tons of wet bean dregs can be processed per hour. The dry bean dregs prepared by the method have low moisture content, low protein content and high dietary fiber content, and are high-quality raw materials for cat litter. At the same time, the dry bean dregs themselves belong to food processing waste, have certain biological safety, and open up new ways for the comprehensive utilization of wet bean dregs.

Claims

1. A method for producing high dietary fiber cat litter bean dregs, characterized in that: The steps include: (1) Raw material pretreatment: Soybeans are selected as raw materials, and the soybeans are soaked in water and washed to obtain pretreated soybeans; (2) Grinding: The pretreated soybeans are mixed with water for grinding, and the resulting ground paste is subjected to high-speed centrifugation to separate the soy milk and wet dregs; (3) Adding water and stirring: Add water to the wet dregs and stir to remove sticky substances; (4) Filter pressing and dehydration: The wet dregs after adding water and stirring are pumped into a filter press for filtration to obtain pressed dregs; (5) Crushing: crushing the pressed okara to disperse it into loose okara; (6) Steam explosion: steam explosion the crushed okara to obtain pre-dried okara; (7) Airflow flash drying: The pre-dried bean dregs are dried by airflow flash drying to obtain dried bean dregs; (8) Dry grinding: The dried bean dregs are dry ground to obtain high dietary fiber cat litter bean dregs with a moisture content of 10-13wt%, a protein content of ≤11wt%, a crude fiber content of ≤25wt%, and a dietary fiber content of 68-75wt%.

2. The production method according to claim 1, characterized in that: During the soaking in step (1), the mass ratio of soybean to water is 1:3-5, and the soaking time is 8-15 hours.

3. The production method according to claim 1, characterized in that: In step (2), the mass ratio of soybean to water during grinding is 1:4-5; the grinding paste is subjected to 2-3 cycles of high-speed centrifugation.

4. The production method according to claim 1, characterized in that: In step (3), water is added and stirred at a mass ratio of water to wet bean dregs of 4-6:1 for 3-5 minutes.

5. The production method according to claim 1, characterized in that: The pressure during the filtration in step (4) is 0.4-0.6 MPa, and the filtration time is 30-60 minutes.

6. The production method according to claim 1, characterized in that: The steam pressure during steam explosion in step (6) is 0.5-1.0 MPa, and the pressure is maintained for 30-60 s.

7. The production method according to claim 1 or 6, characterized in that: In step (6), a protective agent is added to the bean dregs during steam explosion, wherein the protective agent is calcium alginate gel microspheres, and the preparation method thereof is as follows: dissolving sodium alginate in water to prepare a sodium alginate solution with a mass concentration of 1-2%; adding NaCl with a mass fraction of 0.5-1% to the sodium alginate solution, and stirring evenly to obtain a mixed solution; dripping the mixed solution drop by drop into a CaCl2 solution with a mass concentration of 2-3% with a syringe under stirring in a water bath, and continuing to stir in a water bath until gel is generated, the water bath temperature is 50-60° C., and the water bath stirring time is 20-40 min; washing the product and drying it to obtain the calcium alginate gel microspheres.

8. The production method according to claim 7, characterized in that: The amount of protective agent added is 1~5% of the mass of bean dregs.

9. The production method according to claim 1, characterized in that: In step (7), the air inlet temperature during airflow flash drying is ≥120°C, the air outlet temperature is ≤80°C, and the drying time is 2-4h.

10. The production method according to claim 1, characterized in that: In step (8), the dried bean dregs are crushed into 50-80 meshes.

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