Method for reducing zearalenone in corn protein slurry

Abstract

The invention relates to low-toxicity corn protein powder and a preparation method thereof. Specifically, the invention provides a method for reducing zearalenone in corn protein pulp, and the method comprises the following steps: treating the corn protein pulp at low temperature under an alkaline condition; wherein the low temperature is not higher than 15 DEG C. Compared with a traditional process, the preparation process of the low-toxicity corn protein powder has the advantages that the content of aflatoxin in the corn protein powder can be reduced by 90% or above, the content of zearalenone can be reduced by 75% or above, and the content of eight essential amino acids in the corn protein powder can be increased by 20% or above.

Description

Technical Field

[0001] The present invention relates to the technical field of detoxification of corn protein powder, and particularly relates to a low-toxicity corn protein powder and a preparation method thereof. Background Art

[0002] Corn protein powder, also known as corn gluten meal, is a by-product in the production process of corn starch. It is made from corn crude starch milk prepared by the wet milling process through steps such as hydrolysis, separation, concentration, and drying, and is mainly applied to the feed industry. However, corn is prone to be contaminated by zearalenone toxin (ZEN) and aflatoxin (AFB1) during growth and storage, and the toxins will enrich in corn protein during the processing, resulting in the excessive content of zearalenone and aflatoxin in corn protein powder.

[0003] At present, for the removal of ZEN and AFB1 in feed, more research is focused on biological methods. Although such methods can effectively degrade toxins, they require large investments and are difficult to be applied on a large scale in industrialization. Summary of the Invention

[0004] The present invention provides a preparation process of low-toxicity corn protein powder. Compared with the traditional process, this process can reduce the aflatoxin content in corn protein powder by more than 90%, reduce the zearalenone content by more than 75%, and increase the content of 8 essential amino acids in corn protein powder by more than 20%.

[0005] The present invention first provides a method for reducing zearalenone in corn protein slurry, which includes treating the corn protein slurry at low temperature under alkaline conditions; wherein, the low temperature is not higher than 15°C.

[0006] In one or more embodiments, the alkaline condition is that the pH value of the corn protein slurry is 9 - 12, preferably 9 - 11 or 9.5 - 10.5.

[0007] In one or more embodiments, the low temperature is 2 - 12°C or 2 - 10°C, preferably 2 - 8°C, and more preferably 4 - 8°C.

[0008] In one or more embodiments, the treatment is to mix and stir the corn protein slurry with an alkaline solution, and the mixing mass ratio of the corn protein slurry to the alkaline solution is 1:(0.5 - 3), preferably 1:(0.5 - 1.5).

[0009] In one or more embodiments, the rotation speed of the stirring is 30 - 50 rpm.

[0010] In one or more embodiments, the stirring time is 1 - 5 minutes, preferably 1 - 3 minutes, and more preferably 1 - 2 minutes.

[0011] In one or more embodiments, the zein slurry is prepared from corn that has been washed with alkali.

[0012] In one or more embodiments, the pH value of the alkaline solution for alkali washing is 9 - 12, preferably 9 - 11 or 9.5 - 10.5.

[0013] In one or more embodiments, the alkaline solution for alkali washing is sodium hydroxide.

[0014] In one or more embodiments, the method further includes the steps of soaking the corn, crushing and grinding, and separating to prepare the zein slurry.

[0015] In one or more embodiments, the soaking step has one or more of the following characteristics:

[0016] (1) The soaking solution contains sulfurous acid, preferably an aqueous solution of sulfurous acid;

[0017] (2) The content of SO2 in the soaking solution is 0.1 - 0.5 wt%, preferably 0.2 - 0.3%;

[0018] (3) The temperature of the soaking is 40 - 50 °C, preferably 40 - 45 °C;

[0019] (4) The time of the soaking is 40 - 72 hours, preferably 48 - 72 hours.

[0020] In one or more embodiments, the crushing and grinding has one or more of the following characteristics:

[0021] (1) Separating the germ from the crushed corn;

[0022] (2) Grinding the crushed corn to a D90 of 100 - 200 mesh;

[0023] (3) Screening the crushed corn to obtain a starch suspension, and the screen aperture is 30 - 50 mesh or 30 - 40 mesh.

[0024] In one or more embodiments, the separation has one or more of the following characteristics:

[0025] (1) The separation is centrifuging the starch suspension after crushing and grinding;

[0026] (2) The rotational speed of the centrifugation is 1000 - 2500 rpm or 1200 - 1800 rpm;

[0027] (3) The time of the centrifugation is 5 - 30 minutes or 12 - 20 minutes;

[0028] In one or more embodiments, before the soaking step, it further includes the step of alkali-washing corn in the method as described in claim 3.

[0029] The second aspect of the present invention also provides a method for reducing zearalenone toxin and aflatoxin, the method comprising the following steps:

[0030] (1) Cleaning: Cleaning corn kernels with a NaOH solution having a pH of 9 to 12; wherein, the mass ratio of corn kernels to the NaOH solution is 1:1 to 10; after cleaning, separating the corn kernels and draining the surface moisture;

[0031] (2) Soaking: Soaking the surface-drained corn kernels with a sulfurous acid solution; wherein, the SO2 content in the soaking solution is 0.1 to 0.5%, the temperature of the soaking solution is 40 to 50 °C, and the soaking time is 40 to 72 h;

[0032] (3) Crushing and grinding: After soaking, the corn is crushed, the germ is separated and removed, the endosperm is ground to D90 between 100 and 200 meshes, and then passed through a 40-mesh sieve to screen out the fibers therein to obtain a starch suspension;

[0033] (4) Centrifugation: Centrifuging the starch suspension to separate out the corn protein slurry, allowing the corn protein slurry to stand for natural sedimentation until the supernatant is clear and transparent, removing an appropriate amount of the supernatant to obtain a concentrated protein slurry;

[0034] (5) Mixing the concentrated protein slurry and an alkaline solution, and stirring for 1 to 5 minutes when the temperature of the obtained mixture is below 15 °C;

[0035] (6) Filtration: Filtering the stirred mixture in step (5) to obtain a corn protein slurry;

[0036] (7) Optional drying.

[0037] In one or more embodiments, the pH of the alkaline solution is 9 to 12, preferably 9 to 11 or 9.5 to 10.5.

[0038] In one or more embodiments, the alkaline solution is a sodium hydroxide solution.

[0039] In one or more embodiments, the mixing mass ratio of the corn protein slurry to the alkaline solution is 1:(0.5 to 3), preferably 1:(0.5 to 1.5).

[0040] In one or more embodiments, the pH of the mixture is 9 to 12, preferably 9 to 11 or 9.5 to 10.5.

[0041] The third aspect of the present invention provides a corn protein powder prepared by the method described in any one of the present invention, and the corn protein powder is a corn protein powder obtained by filtering and drying the corn protein slurry;

[0042] In one or more embodiments, in the corn protein powder, the content of zearalenone is less than or equal to 1000 ppb, preferably less than or equal to 700 ppb, and more preferably less than or equal to 450 ppb.

[0043] In one or more embodiments, in the corn protein powder, the total content of essential amino acids is greater than or equal to 20%, preferably greater than or equal to 23%, and more preferably greater than or equal to 25%.

[0044] In one or more embodiments, in the corn protein powder, the content of aflatoxin B1 is less than or equal to 6.5 ppb, preferably less than or equal to 6.3 ppb, and more preferably less than or equal to 6.0 ppb;

[0045] The fourth aspect of the present invention provides an application of a method for low-temperature alkaline filtration treatment of corn protein slurry in increasing the content of essential amino acids in corn protein powder and / or reducing zearalenone in corn protein powder. The low temperature is not higher than 15 °C, and the alkalinity is such that the pH of the corn protein slurry is 9-12.

[0046] In one or more embodiments, the low temperature is 2-12 °C, more preferably 2-10 °C, more preferably 2-8 °C, and more preferably 4-8 °C.

[0047] In one or more embodiments, the alkalinity is such that the pH of the corn protein slurry is 9-11 or 9.5-10.5.

[0048] In one or more embodiments, the application further includes reducing aflatoxin in the corn protein powder, and the corn protein slurry is a corn protein slurry prepared from corn that has been alkali-washed.

[0049] The fifth aspect of the present invention further provides a feed containing the corn protein slurry or corn protein powder described in any one of the embodiments of the present invention.

[0050] The sixth aspect of the present invention further provides an application of the corn protein slurry or corn protein powder described in any one of the embodiments of the present invention in preparing a feed. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of the preparation process of low-toxic corn protein. DETAILED DESCRIPTION OF THE INVENTION

[0052] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meanings understood by those skilled in the art with respect to the present invention. In case of conflict, the definitions in this specification shall prevail.

[0053] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not in any way limit the scope of the present invention, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0054] In this document, the terms "comprising", "including", "containing" and similar terms cover the meanings of "consisting essentially of" and "consisting of". For example, when it is disclosed herein that "A comprises B and C", it should be considered that "A consists essentially of B and C" and "A consists of B and C" have been disclosed herein.

[0055] In this document, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the ranges (including integers and fractions).

[0056] In this document, unless otherwise specified, the percentage refers to the mass percentage and the ratio refers to the mass ratio.

[0057] In this document, the sum of the percentage contents of the components of the composition is 100%.

[0058] In this document, essential amino acids refer to lysine, tryptophan, phenylalanine, leucine, isoleucine, methionine, valine and threonine.

[0059] In this document, when describing the embodiments or examples, it should be understood that it is not used to limit the present invention to these embodiments or examples. On the contrary, all alternatives, modifications and equivalents of the methods and materials described in the present invention can be covered within the scope defined by the claims.

[0060] In this document, for the sake of brevity of description, not all possible combinations of all technical features in each embodiment or example are described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope described in this specification.

[0061] In the process of preparing corn protein powder, the traditional process includes steps of acid solution soaking, crushing and grinding, centrifugal drying, and filtration, but the content of toxins in the obtained protein powder is still relatively high. However, through in-depth research, the inventor found that by stirring the mixture of corn protein slurry and an alkaline solution at low temperature for a period of time and then filtering, the content of zearalenone in corn protein powder can be significantly reduced. In some embodiments, adopting the solution of the present invention can also increase the content of essential amino acids in corn protein powder. Thus, the present invention is completed.

[0062] Therefore, the present text provides a method for reducing zearalenone in corn protein slurry, which method includes treating the corn protein slurry at low temperature under alkaline conditions.

[0063] In the present text, corn protein slurry, which is also known as corn steep liquor in the art, is a product of the corn starch soaking process and is one of the by-products of corn deep processing enterprises. Corn protein slurry is rich in soluble proteins, trace elements, vitamins and some precursor substances, and generally contains about 40-50% of solid substances.

[0064] The corn protein slurry applicable to the present text can be the corn protein slurry obtained by various methods well-known in the art but with an excessive zearalenone content that needs further treatment.

[0065] Generally speaking, the preparation method of corn protein slurry includes steps such as soaking, crushing and grinding, and separation.

[0066] Usually, the washed corn kernels are soaked in a soaking solution containing sulfurous acid. Preferably, the soaking solution is an aqueous solution of sulfurous acid. The content of SO2 in the soaking solution can be in the range of 0.1-0.5 wt%, preferably 0.2-0.3%. The soaking temperature can be 40-50 °C, preferably 40-45 °C, and the soaking time can be 40-72 hours, preferably 48-72 hours. After soaking, the soaking solution is filtered off.

[0067] In the present text, the purpose of crushing is to separate and remove the germ. The soaked corn can be crushed by using equipment and techniques well-known in the art to remove the germ. Usually, the separated endosperm is ground to D90 of 100-200 mesh, and then it is passed through a 40-mesh sieve. Water can be added during the sieving process to obtain a starch suspension.

[0068] In the present text, the corn protein slurry can be separated by centrifuging the starch suspension. There are no special restrictions on the centrifugation parameters, and conventional parameters can be used for centrifugation. For example, the process parameters of centrifugation can be 1000-2500 rpm, and the time can be 5-30 minutes. In some embodiments, it is centrifuged at a speed of 1200-1800 rpm for 12-20 minutes.

[0069] In some embodiments, a concentration step is further included after the separation step. For example, the corn protein slurry can be allowed to stand still to cause natural precipitation until the supernatant is clear and transparent, and then an appropriate amount of the supernatant is removed to obtain a moderately concentrated corn protein slurry. For example, in some embodiments, a concentrated corn protein slurry with a water content of ≤84 wt% can be obtained.

[0070] In this text, the low temperature is not higher than 15°C, preferably 2 - 12°C, more preferably 2 - 10°C, more preferably 2 - 8°C, and even more preferably 4 - 8°C.

[0071] In this text, there are no special restrictions on the temperature of the corn protein slurry and the alkaline solution before mixing. Their respective temperatures can be the same or different, and can both be at room temperature (such as room temperature), both not higher than 15°C, or be room temperature and not higher than 15°C respectively. For example, the corn protein slurry and the alkaline solution at the same room temperature can be mixed, and then the temperature of the mixed solution is lowered to the low temperature described in this text. Or, the temperatures of the corn protein slurry and the alkaline solution can be cooled to the low temperature described in this text respectively, and then the two are mixed. Or, one of the corn soya bean powder and the alkaline solution is at room temperature and the other is at the low temperature described in this text. After mixing, it is determined whether further cooling to the low temperature described in this text is required according to the temperature of the mixed solution. The temperature can be lowered by a method well known in the art, for example, placed in a low-temperature environment. In a preferred embodiment, the temperatures of the corn protein slurry and the alkaline solution are both lowered to the low-temperature range described in this text, preferably lowered to below 10°C, and then the two are mixed.

[0072] The pH of the alkaline solution used for mixing with the corn protein slurry can be 9 - 12, preferably 9 - 11 or 9.5 - 10.5. Preferably, the alkali solution is a NaOH solution. The alkaline solution can be a freshly prepared alkaline solution or the waste liquid separated after the cleaning in the alkali washing step described above. Preferably, the waste liquid is filtered to remove impurities and then concentrated to a certain extent. The main purpose of concentration is to reduce the amount of the alkali solution used, so that the amount of the alkali solution reaches the amount used for mixing with the corn protein slurry. In some embodiments, the mixing mass ratio of the corn protein slurry to the alkali solution is 1:(0.5 - 3), preferably 1:(0.5 - 1.5).

[0073] In this text, the low-temperature mixed solution is stirred. The stirring speed can be 30 - 50 rpm. The stirring time can be 1 - 5 minutes. In some embodiments, the inventors found that if the stirring time is too long, it may cause excessive loss of essential amino acids (including lysine, tryptophan, phenylalanine, leucine, methionine, isoleucine, valine, threonine) in the corn protein slurry. Therefore, in a preferred embodiment, the stirring time is controlled within 1 - 3 minutes, and more preferably 1 - 2 minutes.

[0074] After stirring and filtering, the corn protein slurry with reduced zearalenone content of the present invention can be obtained. The present invention has no special requirements for filtration, and conventional methods or instruments in the art can be used for filtration, such as plate and frame filter presses. After filtration, if necessary, the corn protein slurry can be dried to obtain corn protein powder. Usually, the moisture content of the corn protein powder is < 14 wt%.

[0075] Therefore, in some embodiments, the present invention provides a method for reducing zearalenone in corn protein slurry, which comprises: treating the corn protein slurry at low temperature under alkaline conditions, wherein the alkaline conditions are such that the pH of the corn protein slurry is 9 - 12, preferably 9 - 11 or 9.5 - 10.5, and the low temperature is such that the temperature of the corn protein slurry is 2 - 12 °C, more preferably 2 - 10 °C, more preferably 2 - 8 °C, more preferably 4 - 8 °C, and the treatment is stirring. Preferably, the stirring speed can be 30 - 50 rpm. Preferably, the stirring time is 1 - 5 minutes, preferably 1 - 3 minutes, more preferably 1 - 2 minutes.

[0076] In some embodiments, the method for reducing zearalenone toxin in corn protein slurry described herein further comprises the step of preparing corn protein slurry. Preferably, the method for preparing the corn protein slurry comprises the soaking, crushing and grinding, and separation steps described herein. Preferably, the method for preparing the corn protein slurry further comprises the step of washing with an alkaline solution described herein before the soaking step. Preferably, the method for preparing the corn protein slurry further comprises the concentration step described herein after the separation step.

[0077] The inventors also found that preparing the corn protein slurry of the present invention by alkali-washing corn raw materials can further remove aflatoxin in the corn protein powder.

[0078] Therefore, in some embodiments, the method for preparing the corn protein slurry further comprises an alkali-washing step before the soaking step. Preferably, it is washed with an alkaline solution having a pH of 9 - 12. The alkaline solution is preferably a NaOH solution. In some embodiments, it is washed with an alkaline solution having a pH of 9 - 11, preferably 9.5 - 10.5. During alkali-washing, usually the mass ratio of corn kernels to the alkaline solution can be 1:1 - 10, such as 1:1 - 5 or 1:2 - 4. The alkali-washing time is not limited and is based on being washed clean, usually 1 - 10 minutes, such as 1 - 5 minutes or 1 - 3 minutes.

[0079] In some embodiments, the lye separated from corn obtained in the caustic washing step can be used to mix with corn gluten meal to provide an alkaline condition. Since a relatively large amount of lye is used in the alkaline step, the lye can be concentrated first and then mixed with corn gluten meal. Conventional methods can be used for concentration, such as evaporation. Generally, the pH of the concentrated lye does not change much and remains within the pH range described herein. If it is not within this range, an appropriate amount of sodium hydroxide can be added to adjust the pH of the lye to the pH range described herein. Since methods such as evaporation are used for concentration, the temperature of the lye is generally relatively high, and it can be cooled before mixing with the corn gluten meal to be detoxified. It should be understood that, as described above, as long as the temperature of the resulting mixture is within the low temperature range described herein. The mixing mass ratio of corn gluten meal to the lye can be 1:(0.5 - 3), preferably 1:(0.5 - 1.5).

[0080] In some embodiments, the present disclosure also provides a method for reducing zearalenone and aflatoxin in corn gluten meal, the method comprising the steps of preparing corn gluten meal as described herein and treating the corn gluten meal at low temperature under alkaline conditions.

[0081] In some embodiments, the method for reducing zearalenone toxin and aflatoxin in corn gluten meal as described herein comprises the following steps:

[0082] (1) Cleaning: Cleaning corn kernels with a NaOH solution having a pH of 9 - 12, wherein the mass ratio of corn kernels to the NaOH solution is 1:1 - 10; separating the corn kernels after cleaning and draining the surface moisture;

[0083] (2) Soaking: Soaking the surface-drained corn kernels with a sulfurous acid solution, wherein the SO2 content in the soaking solution is 0.1 - 0.5%, the temperature of the soaking solution is 40 - 50 °C, and the soaking time is 40 - 72 h;

[0084] (3) Crushing and grinding: After soaking, the corn is crushed, the germ is separated and removed, the endosperm is ground to a D90 between 100 - 200 mesh, and then passed through a 40-mesh sieve to screen out the fibers therein to obtain a starch suspension;

[0085] (4) Centrifugation: Centrifuging the starch suspension to separate out corn gluten meal, allowing the corn gluten meal to stand for natural sedimentation until the supernatant is clear and transparent, and removing an appropriate amount of the supernatant to obtain a concentrated protein slurry;

[0086] (5) Mixing the concentrated protein slurry and an alkaline solution, and stirring for 1 - 5 minutes when the temperature of the resulting mixture is below 15 °C;

[0087] (6) Filtration: Filtering the mixture after stirring in step (5) to obtain corn gluten meal;

[0088] (7) Optional drying;

[0089] It should be understood that each step of the method can be implemented with the process parameters described above.

[0090] In some embodiments, the present invention also provides corn protein powder obtained by filtering and drying corn protein slurry as described herein. Preferably, the moisture content of the corn protein powder is less than 15%, and more preferably, the water content of the corn protein powder is less than 14%.

[0091] In some embodiments, in the corn protein powder, the content of zearalenone is less than or equal to 1000 ppb, preferably less than or equal to 700 ppb, and more preferably less than or equal to 450 ppb; the total content of essential amino acids is greater than or equal to 20%, preferably greater than or equal to 23%, and more preferably greater than or equal to 25%. In some embodiments, in the corn protein powder, the content of aflatoxin B1 is less than or equal to 6.5 ppb, preferably less than or equal to 6.3 ppb, and more preferably less than or equal to 6.0 ppb.

[0092] The present invention also provides feeds containing the corn protein slurry or corn protein powder described in any of the embodiments herein, including but not limited to livestock feeds such as pig feed, cattle feed, and sheep feed, poultry feeds such as chicken feed, duck feed, and goose feed, and pet feeds such as cat feed and dog feed. In this feed, based on the total weight of the feed, the content of corn protein powder or corn protein slurry is 5-20%.

[0093] The present invention has the following beneficial effects:

[0094] The preparation process of the low-toxic corn protein powder of the present invention, compared with the traditional process, can reduce the aflatoxin content in the corn protein powder by more than 90%, reduce the zearalenone content by more than 75%, and can increase the content of 8 essential amino acids in the corn protein powder by more than 20%.

[0095] The present invention will be further described below by way of specific examples. It should be understood that these examples are merely illustrative and not intended to limit the scope of the present invention. The methods and reagents used in the examples are conventional methods and reagents in the art unless otherwise specified.

[0096] Detection method

[0097] Aflatoxin B1: Refer to the high performance liquid chromatography - post-column derivation method (Method 3) in GB 5009.22 - 2016.

[0098] Zearalenone (ZEN): Refer to the liquid chromatography method (Method 1) in GB 5009.209 - 2016.

[0099] Amino acid content: Refer to the determination of amino acids in feeds in GB / T 18246-2019.

[0100] Moisture content: Refer to the direct drying method in GB / T 6435-2014.

[0101] Sulfur dioxide content in the solution: Refer to the acid-base titration method (the first method) in GB 5009.34-2022.

[0102] Example 1

[0103] (1) Cleaning: Clean 500 kg of corn kernels for 1 min with a solid-liquid ratio of 1:3. The cleaning solution is a NaOH solution with pH = 11. Drain the surface of the corn kernels, and reserve the alkaline waste liquid after cleaning the corn.

[0104] (2) Soaking: Transfer the surface-drained corn kernels into a soaking tank and add a sulfurous acid solution (SO2 = 5 wt%), so that the SO2 content in the soaking solution is 0.2%, keep the temperature at 45 °C, and soak for 48 h.

[0105] (3) Crushing and grinding: After soaking, the corn is crushed and the germ is separated and removed. Grind the endosperm to D90 between 100 and 200 mesh, then pass through a 40-mesh sieve to screen out the fibers, obtaining a starch suspension.

[0106] (4) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, send it to a storage tank and let it settle naturally until the supernatant is clear and transparent. Remove the supernatant to obtain a 16% concentrated protein slurry, and then cool the concentrated protein slurry to 6 °C.

[0107] (5) Mixing: Filter and remove impurities from the waste liquid after cleaning the corn in step (1), evaporate and concentrate it to 1 / 10 of the original volume (150 kg), adjust the pH = 12, cool it to 6 °C, and add it to the concentrated protein slurry (150 kg) in step (4). Keep the temperature of the protein slurry at 6 °C and stir at 40 rpm for 1 min.

[0108] (6) Drying: Take a part of the stirred protein slurry sample, dry it directly without filtration until the moisture content is less than 14%, and measure that the content of ZEN in the dried protein powder is 1693.17 ppb; Filter a part of the stirred protein slurry and then dry it until the moisture content is less than 14% to obtain corn protein powder 1.

[0109] Example 2

[0110] (1) Cleaning: Clean 500 kg of corn kernels for 2 min with a solid-liquid ratio of 1:3. The cleaning solution is a NaOH solution with pH = 9. Drain the surface of the corn kernels, and reserve the alkaline waste liquid after cleaning the corn.

[0111] (2) Soaking: Convey the corn kernels with drained surfaces into the soaking tank, and add sulfurous acid solution (SO2 = 5wt%), so that the SO2 content in the soaking liquid is 0.3%, keep the temperature at 40°C, and soak for 72h;

[0112] (3) Crushing and grinding: After the soaking is completed, the corn is crushed and separated to completely separate the germ from the endosperm. The remaining endosperm is ground to D90 between 100 - 200 mesh, and then passed through a 40 - mesh sieve to screen out the fibers therein, obtaining a starch suspension;

[0113] (4) Centrifugation: Centrifuge the starch suspension (1500rpm, 15 minutes), separate the corn protein slurry, send it into the storage tank and let it settle naturally until the supernatant is clear and transparent. Remove the supernatant to obtain an 18% concentrated protein slurry, and then cool the concentrated protein slurry to 8°C;

[0114] (5) Mixing: Filter and remove impurities from the waste liquid after cleaning the corn in step (1), evaporate and concentrate it to 1 / 10 of the original volume (150kg), adjust the pH = 10, cool it to 8°C, and add it to the concentrated protein slurry (150kg) in step (4). Keep the temperature of the protein slurry at 8°C and stir at 30rpm for 2min;

[0115] (6) Drying: Take a part of the stirred protein slurry sample, dry it directly without filtration until the moisture content is less than 14%, and measure that the content of ZEN in the dried protein powder is 1706.53ppb; Filter a part of the stirred protein slurry and then dry it until the moisture content is less than 14% to obtain corn protein powder 2.

[0116] Example 3

[0117] (1) Cleaning: Clean 500kg of corn kernels for 2min, with a solid - liquid ratio of 1:3. Among them, the cleaning liquid is a NaOH solution with pH = 10. Drain the surfaces of the corn kernels, and keep the alkaline waste liquid after cleaning the corn for later use;

[0118] (2) Soaking: Convey the corn kernels with drained surfaces into the soaking tank, and add sulfurous acid solution (SO2 = 5wt%), so that the SO2 content in the soaking liquid is 0.25%, keep the temperature at 45°C, and soak for 60h;

[0119] (3) Crushing and grinding: After the soaking is completed, the corn is crushed and separated to completely separate the germ from the endosperm. The remaining endosperm is ground to D90 between 100 - 200 mesh, and then passed through a 40 - mesh sieve to screen out the fibers therein, obtaining a starch suspension;

[0120] (4) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, transfer it to a storage tank and let it settle naturally until the supernatant is clear and transparent. Remove the supernatant to obtain a 17% concentrated protein slurry, and then cool the concentrated protein slurry to 4°C;

[0121] (5) Mixing: Filter and remove impurities from the waste liquid after washing the corn in step (1), evaporate and concentrate it to 1 / 10 of the original volume (150 kg), adjust the pH to 11, cool it to 4°C, and add it to the concentrated protein slurry (150 kg) in step (4). Keep the temperature of the protein slurry at 4°C and stir at 50 rpm for 1 min;

[0122] (6) Drying: Take a part of the stirred protein slurry sample, dry it directly without filtration until the moisture content is less than 14%, and measure the content of ZEN in the dried protein powder to be 1687.49 ppb; Filter a part of the stirred protein slurry and then dry it until the moisture content is less than 14% to obtain corn protein powder 3.

[0123] Example 4

[0124] (1) Washing: Wash 500 kg of corn kernels for 2 min with a solid-liquid ratio of 1:3. Among them, the washing liquid is a NaOH solution with a pH of 9. Drain the surface of the corn kernels, and keep the alkaline waste liquid after washing the corn for later use;

[0125] (2) Soaking: Transfer the surface-drained corn kernels into a soaking tank and add a sulfurous acid solution (SO2 = 5 wt%) to make the SO2 content in the soaking liquid 0.3%, keep the temperature at 40°C, and soak for 72 h;

[0126] (3) Crushing and grinding: After soaking, the corn is crushed and separated to completely separate the germ from the endosperm. The remaining endosperm is ground to a D90 between 100 and 200 mesh, and then passed through a 40-mesh sieve to screen out the fibers therein to obtain a starch suspension;

[0127] (4) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, transfer it to a storage tank and let it settle naturally until the supernatant is clear and transparent. Remove the supernatant to obtain an 18% concentrated protein slurry, and then cool the concentrated protein slurry to 8°C;

[0128] (5) Mixing: Add 150 kg of sodium hydroxide solution with a pH of 11 to the concentrated protein slurry (150 kg) in step (4), and cool the protein slurry to 8°C, stir at 50 rpm for 2 min;

[0129] (6) Drying: Take a part of the stirred protein slurry sample without filtration and directly dry it until the moisture content is less than 14%. The content of ZEN in the dried protein powder is measured to be 1700.72 ppb; Filter a part of the stirred protein slurry and then dry it until the moisture content is less than 14% to obtain corn protein powder 4.

[0130] Example 5

[0131] (1) Cleaning: Wash 500 kg of corn kernels for 2 min with a solid-liquid ratio of 1:3. The cleaning solution is a NaOH solution with pH = 9. Drain the surface of the corn kernels, and keep the alkaline waste liquid after cleaning the corn for later use;

[0132] (2) Soaking: Convey the corn kernels with drained surface into the soaking tank and add a sulfurous acid solution with a certain concentration (SO2 = 5 wt%) to make the SO2 content in the soaking solution 0.3%, keep the temperature at 40 °C, and soak for 72 h;

[0133] (3) Crushing and grinding: After soaking, the corn is crushed and separated to completely separate the germ from the endosperm. The remaining endosperm is ground to D90 between 100 and 200 meshes, and then sieved through a 40-mesh sieve to separate the fibers, obtaining a starch suspension;

[0134] (4) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, send it to the storage tank to naturally settle until the supernatant is clear and transparent, remove the supernatant to obtain 18% concentrated protein slurry, and then cool the concentrated protein slurry to 15 °C;

[0135] (5) Mixing: Filter and remove impurities from the waste liquid after cleaning the corn in step (1), evaporate and concentrate it to 1 / 10 of the original volume (150 kg), adjust the pH = 10, cool it to 6 °C, add it to the concentrated protein slurry (150 kg) in step (4), keep the temperature of the protein slurry at 12 °C, and stir at 30 rpm for 2 min;

[0136] (6) Drying: Take a part of the stirred protein slurry sample without filtration and directly dry it until the moisture content is less than 14%. The content of ZEN in the dried protein powder is measured to be 1698.03 ppb; Filter a part of the stirred protein slurry and then dry it until the moisture content is less than 14% to obtain corn protein powder 5.

[0137] Example 6

[0138] (1) Cleaning: Wash 500 kg of corn kernels for 2 min with a solid-liquid ratio of 1:3. The cleaning solution is a NaOH solution with pH = 10. Drain the surface of the corn kernels, and keep the alkaline waste liquid after cleaning the corn for later use;

[0139] (2) Soaking: Transfer the corn kernels with drained surfaces into the soaking tank, and add sulfurous acid solution (SO2 = 5 wt%), so that the SO2 content in the soaking solution is 0.25%, keep the temperature at 45°C, and soak for 60 h;

[0140] (3) Crushing and grinding: After soaking, the corn is crushed and separated to completely separate the germ from the endosperm. The remaining endosperm is ground to D90 between 100 - 200 mesh, and then passed through a 40 - mesh sieve to screen out the fibers therein, obtaining a starch suspension;

[0141] (4) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, send it into the storage tank and let it settle naturally until the supernatant is clear and transparent. Remove the supernatant to obtain a 17% concentrated protein slurry, and then cool the concentrated protein slurry to 4°C;

[0142] (5) Mixing: Filter and remove impurities from the waste liquid after washing the corn in step (1), evaporate and concentrate it to 1 / 10 of the original volume (150 kg), adjust the pH = 11, cool it to 4°C, and add it to the concentrated protein slurry (150 kg) in step (4). Keep the temperature of the protein slurry at 4°C and stir at 50 rpm for 5 min;

[0143] (6) Drying: Take a part of the stirred protein slurry sample, dry it directly without filtration until the moisture content is less than 14%, and measure that the content of ZEN in the dried protein powder is 1681.44 ppb; Filter a part of the stirred protein slurry and then dry it until the moisture content is less than 14% to obtain corn protein powder 6.

[0144] Example 7

[0145] (1) Cleaning: Clean 500 kg of corn kernels for 1 min, with a solid - liquid ratio of 1:3. Among them, the cleaning solution is a NaOH solution with pH = 11. Drain the surfaces of the corn kernels, and keep the alkaline waste liquid after cleaning the corn for later use;

[0146] (2) Soaking: Transfer the corn kernels with drained surfaces into the soaking tank, and add sulfurous acid solution (SO2 = 5 wt%), so that the SO2 content in the soaking solution is 0.2%, keep the temperature at 45°C, and soak for 48 h;

[0147] (3) Crushing and grinding: After soaking, the corn is crushed and the germ is removed. Grind the endosperm to D90 between 100 - 200 mesh, and then pass through a 40 - mesh sieve to screen out the fibers therein, obtaining a starch suspension;

[0148] (4) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, send it into the storage tank and let it settle naturally until the supernatant is clear and transparent. Remove the supernatant to obtain a 16% concentrated protein slurry at room temperature;

[0149] (5) Mixing: Filter and remove impurities from the waste liquid after cleaning the corn in step (1). After evaporating and concentrating it to 1 / 10 of the original volume (150 kg), adjust the pH to 12 at room temperature, add it to the concentrated protein slurry (150 kg) in step (4), cool the mixed protein slurry to 6°C, and stir it at 40 rpm for 1 min;

[0150] (6) Drying: Take a part of the stirred protein slurry sample, dry it directly without filtration until the moisture content is less than 14%, and measure that the content of ZEN in the dried protein powder is 1699.01 ppb; Filter a part of the stirred protein slurry and then dry it until the moisture content is less than 14% to obtain corn protein powder 7.

[0151] Example 8

[0152] (1) Cleaning: Clean 500 kg of corn kernels for 1 min, with a solid-liquid ratio of 1:3. Among them, the cleaning liquid is a NaOH solution with pH = 11. Drain the surface of the corn kernels, and keep the alkaline waste liquid after cleaning the corn for later use;

[0153] (2) Soaking: Convey the corn kernels with drained surface into the soaking tank, and add sulfurous acid solution (SO2 = 5 wt%), so that the SO2 content in the soaking liquid is 0.2%, keep the temperature at 45°C, and soak for 48 h;

[0154] (3) Crushing and grinding: After soaking, the corn is crushed and the germ is separated and removed. Grind the endosperm until D90 is between 100 and 200 mesh, and then pass through a 40-mesh sieve to screen out the fibers therein to obtain a starch suspension;

[0155] (4) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, send it into the storage tank and let it settle naturally until the supernatant is clear and transparent, remove the supernatant to obtain a 16% room temperature concentrated protein slurry;

[0156] (5) Mixing: Filter and remove impurities from the waste liquid after cleaning the corn in step (1). After evaporating and concentrating it to 1 / 10 of the original volume (150 kg), adjust the pH to 12, cool it to 6°C, add it to the concentrated protein slurry (150 kg) in step (4), cool the mixed protein slurry to 6°C, and stir it at 40 rpm for 1 min;

[0157] (6) Drying: Take a part of the stirred protein slurry sample, dry it directly without filtration until the moisture content is less than 14%, and measure that the content of ZEN in the dried protein powder is 1684.47 ppb; Filter a part of the stirred protein slurry and then dry it until the moisture content is less than 14% to obtain corn protein powder 8.

[0158] Example 9

[0159] (1) Cleaning: Clean 500 kg of corn kernels for 1 min with a solid-liquid ratio of 1:3. The cleaning liquid is a NaOH solution with pH = 11. Drain the surface of the corn kernels, and reserve the alkaline waste liquid after cleaning the corn.

[0160] (2) Soaking: Convey the corn kernels with drained surfaces into a soaking tank, and add a sulfurous acid solution (SO2 = 5 wt%), so that the SO2 content in the soaking liquid is 0.2%, keep the temperature at 45 °C, and soak for 48 h.

[0161] (3) Crushing and grinding: After soaking, the corn is crushed and the germ is separated. Grind the endosperm to D90 between 100 - 200 mesh, then pass through a 40-mesh sieve to screen out the fibers, and obtain a starch suspension.

[0162] (4) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, send it into a storage tank to naturally settle until the supernatant is clear and transparent, remove the supernatant to obtain a 16% concentrated protein slurry, and then cool the concentrated protein slurry to 6 °C.

[0163] (5) Mixing: Filter and remove impurities from the waste liquid after cleaning the corn in step (1). Evaporate and concentrate it to 1 / 10 of the original volume (150 kg), adjust the pH = 12 at room temperature, add it to the concentrated protein slurry (150 kg) in step (4), cool the mixed protein slurry to 6 °C, and stir at 40 rpm for 1 min.

[0164] (6) Drying: Take a part of the stirred protein slurry sample, dry it directly without filtration until the moisture content is less than 14%, and measure that the content of ZEN in the dried protein powder is 1685.28 ppb; Filter a part of the stirred protein slurry, and then dry it until the moisture content is less than 14% to obtain corn protein powder 9.

[0165] Example 10

[0166] (1) Soaking: Convey 500 kg of purified and impurity-removed corn kernels into a soaking tank, and add a sulfurous acid solution (SO2 = 5 wt%), so that the SO2 content in the soaking liquid is 0.2%, keep the temperature at 45 °C, and soak for 48 h.

[0167] (2) Crushing and grinding: After soaking, the corn is crushed and the germ is separated. Grind the endosperm to D90 between 100 - 200 mesh, then pass through a 40-mesh sieve to screen out the fibers, and obtain a starch suspension.

[0168] (3) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, send it into a storage tank to naturally settle until the supernatant is clear and transparent, remove the supernatant to obtain a 16% concentrated protein slurry, and then cool the concentrated protein slurry to 8 °C.

[0169] (4) Mixing: Add 150 kg of sodium hydroxide solution with a pH of 11 to the concentrated protein slurry (150 kg) in step (3), cool the protein slurry to 8 °C, and stir at 50 rpm for 2 min;

[0170] (5) Drying: Take a part of the stirred protein slurry sample, without filtration, and directly dry it to a moisture content of less than 14%. The content of ZEN in the dried protein powder is measured to be 1711.97 ppb; Filter a part of the stirred protein slurry, and then dry it to a moisture content of less than 14% to obtain corn protein powder 10.

[0171] Comparative Example 1 (Traditional Process)

[0172] (1) Soaking: After purifying and removing impurities from 500 kg of corn kernels, transfer them to a soaking tank, and add sulfurous acid solution (SO2 = 5 wt%) to make the SO2 content in the soaking liquid 0.2%, keep the temperature at 45 °C, and soak for 48 hours;

[0173] (2) Crushing and Grinding: After soaking, the corn is crushed and separated so that all the germ is separated from the endosperm. The remaining endosperm is ground to D90 between 100 - 200 mesh, and then passed through a 40 - mesh sieve to screen out the fibers therein to obtain a starch suspension;

[0174] (3) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, transfer it to a storage tank and let it settle naturally until the supernatant is clear and transparent, then draw off the supernatant to obtain a 16% concentrated protein slurry;

[0175] (4) Drying: Filter the concentrated protein slurry, and then dry it to a moisture content of less than 14% to obtain corn protein powder 7.

[0176] Comparative Example 2

[0177] (1) Soaking: After purifying and removing impurities from 500 kg of corn kernels, transfer them to a soaking tank, and add sulfurous acid solution (SO2 = 5 wt%) to make the SO2 content in the soaking liquid 0.2%, keep the temperature at 45 °C, and soak for 48 hours;

[0178] (2) Crushing and Grinding: After soaking, the corn is crushed and separated so that all the germ is separated from the endosperm. The remaining endosperm is ground to D90 between 100 - 200 mesh, and then passed through a 40 - mesh sieve to screen out the fibers therein to obtain a starch suspension;

[0179] (3) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, transfer it to a storage tank and let it settle naturally until the supernatant is clear and transparent, then draw off the supernatant to obtain a 16% concentrated protein slurry,

[0180] (4) Cooling: Cool the concentrated protein slurry in (3) to 8°C and stir at 40 rpm for 1 min;

[0181] (5) Drying: Filter the concentrated protein slurry and then dry it to a moisture content of less than 14% to obtain corn protein powder 8.

[0182] Comparative Example 3

[0183] (1) Cleaning: Clean 500 kg of corn kernels for 1 min with a solid-liquid ratio of 1:3. Among them, the cleaning liquid is a NaOH solution with pH = 11. Drain the surface of the corn kernels, and keep the alkaline waste liquid after cleaning the corn for later use;

[0184] (2) Soaking: Convey the corn kernels with drained surfaces into the soaking tank and add a sulfurous acid solution (SO2 = 5 wt%), so that the SO2 content in the soaking liquid is 0.2%, keep the temperature at 45°C, and soak for 48 h;

[0185] (3) Crushing and grinding: After soaking, the corn is crushed and separated so that all the germ is separated from the endosperm. The remaining endosperm is ground to D90 between 100 - 200 meshes, and then sieved through a 40-mesh sieve to screen out the fibers therein to obtain a starch suspension;

[0186] (4) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes) to separate the corn protein slurry, send it into the storage tank and let it settle naturally until the supernatant is clear and transparent, remove the supernatant to obtain a 16% concentrated protein slurry;

[0187] (5) Mixing: Filter and remove impurities from the waste liquid after cleaning the corn in step (1), evaporate and concentrate it to 1 / 10 of the original volume, then adjust the pH = 12, add it to the concentrated protein slurry in step (4), keep the temperature of the protein slurry at 35°C, and stir at 40 rpm for 1 min;

[0188] (6) Drying: Take a part of the stirred protein slurry sample, dry it directly without filtration to a moisture content of less than 14%, and measure that the content of ZEN in the dried protein powder is 1727.59 ppb; Filter a part of the stirred protein slurry and then dry it to a moisture content of less than 14% to obtain corn protein powder 9.

[0189] Comparative Example 4

[0190] (1) Cleaning: Clean 500 kg of corn kernels for 2 min with a solid-liquid ratio of 1:3. Among them, the cleaning liquid is a NaOH solution with pH = 10. Drain the surface of the corn kernels, and keep the alkaline waste liquid after cleaning the corn for later use;

[0191] (2) Soaking: Transfer the corn kernels with drained surfaces into a soaking tank, and add sulfurous acid solution (SO2 = 5 wt%), so that the SO2 content in the soaking solution is 0.25%, keep the temperature at 45°C, and soak for 60 h;

[0192] (3) Crushing and grinding: After soaking, the corn is crushed and separated so that all the germ is separated from the endosperm. The remaining endosperm is ground to D90 between 100 - 200 mesh, and then passed through a 40-mesh sieve to screen out the fibers therein, obtaining a starch suspension;

[0193] (4) Centrifugation: Centrifuge the starch suspension (1500 rpm, 15 minutes), separate the corn protein slurry, send it into a storage tank and let it settle naturally until the supernatant is clear and transparent, remove the supernatant, and obtain a 17% concentrated protein slurry;

[0194] (5) Mixing: Filter and remove impurities from the waste liquid after washing the corn in step (1), evaporate and concentrate it to 1 / 10 of the original volume (150 kg), adjust the pH = 11, and add it to the concentrated protein slurry (150 kg) in step (4);

[0195] (6) High-temperature treatment: Place the mixed protein slurry in step (5) in a sealed container, place the sealed container in an environment with a temperature of 150°C, and conduct high-temperature treatment for 1 h;

[0196] (7) Drying: Take a part of the protein slurry sample after high-temperature treatment, dry it directly without filtration until the moisture content is less than 14%, and measure that the content of ZEN in the dried protein powder is 482.37 ppb; Filter a part of the protein slurry after high-temperature treatment, and then dry it until the moisture content is less than 14% to obtain corn protein powder 10.

[0197] Detect the aflatoxin content, zearalenone content, and total content of 8 essential amino acids (lysine, tryptophan, phenylalanine, leucine, methionine, isoleucine, valine, threonine) in the corn protein powder prepared in each of the above examples and comparative examples. The results are shown in the following table.

[0198] Table 1: Detection results

[0199]

[0200]

Claims

1. A method for reducing zearalenone in corn protein slurry, characterized in that, The method includes treating corn protein slurry at low temperature under alkaline conditions; wherein, the low temperature is not higher than 15°C.

2. The method according to claim 1, wherein The method has one or more of the following characteristics: Under the alkaline conditions, the pH value is 9 - 12, preferably 9 - 11 or 9.5 - 10.5; The low temperature is 2 - 12°C or 2 - 10°C, preferably 2 - 8°C, more preferably 4 - 8°C; The treatment is to mix and stir the corn protein slurry with an alkaline solution, and the mixing mass ratio of the corn protein slurry to the alkaline solution is 1:(0.5 - 3), preferably 1:(0.5 - 1.5); The rotation speed of the stirring is 30 - 50 rpm; and The stirring time is 1 - 5 minutes, preferably 1 - 3 minutes, more preferably 1 - 2 minutes.

3. The method according to claim 1 or 2, characterized in that, The corn protein slurry is prepared from corn that has been alkali - washed; preferably, the pH value of the alkaline solution for alkali - washing is 9 - 12, preferably 9 - 11 or 9.5 - 10.5; more preferably, the alkaline solution for alkali - washing is sodium hydroxide solution; Preferably, the alkali solution separated from the corn after alkali - washing is used to mix with the corn protein slurry to provide the alkaline conditions; preferably, the alkali solution is concentrated before being used to mix with the corn protein slurry.

4. The method according to any one of claims 1 to 3, characterized in that The method further includes the step of preparing corn protein slurry; preferably, the preparation of corn protein slurry includes the steps of soaking corn, crushing and grinding, and separating to obtain corn protein slurry.

5. The method according to claim 4, wherein The soaking step has one or more of the following characteristics: (1) The soaking solution contains sulfurous acid, preferably an aqueous solution of sulfurous acid; (2) The content of SO2 in the soaking solution is 0.1 - 0.5 wt%, preferably 0.2 - 0.3%; (3) The soaking temperature is 40 - 50°C, preferably 40 - 45°C; (4) The soaking time is 40 - 72 hours, preferably 48 - 72 hours; The crushing and grinding has one or more of the following characteristics: (1) Removing the germ from the crushed corn; (2) Grinding the crushed corn to a D90 of 100 - 200 mesh; (3) Screening the crushed corn to obtain a starch suspension, and the screen aperture is 30 - 50 mesh or 30 - 40 mesh; The separation has one or more of the following characteristics: (1) The separation is to centrifuge the starch suspension after crushing and grinding; (2) The rotation speed of the centrifugation is 1000 - 2500 rpm or 1200 - 1800 rpm; (3) The centrifugation time is 5 - 30 minutes or 12 - 20 minutes; Preferably, before the soaking step, there is also the step of alkali - washing corn as described in the method of claim 3.

6. A method for reducing zearalenone toxin and aflatoxin in corn protein slurry, characterized in that, The method includes the preparation of corn protein slurry and the step of treating the corn protein slurry at low temperature under alkaline conditions as described in any one of claims 1 - 5, wherein the preparation of the corn protein slurry includes the step of washing corn grains with a NaOH solution having a pH of 9 - 12. Preferably, the method includes the following steps: (1) Cleaning: Clean the corn kernels with a NaOH solution having a pH of 9 to 12; wherein, the mass ratio of the corn kernels to the NaOH solution is 1:1 to 10; after cleaning, separate the corn kernels and drain the surface moisture; (2) Soaking: Soak the surface-drained corn kernels with a sulfurous acid solution; wherein, the SO2 content in the soaking solution is 0.1 to 0.5%, the temperature of the soaking solution is 40 to 50 °C, and the soaking time is 40 to 72 h; (3) Crushing and grinding: After soaking, the corn is crushed and the germ is separated and removed, and the endosperm is ground to D90 between 100 and 200 mesh, and then sieved through a 40-mesh sieve to separate the fibers therein to obtain a starch suspension; (4) Centrifugation: Centrifuge the starch suspension to separate the corn protein slurry, and let the corn protein slurry stand for natural sedimentation until the supernatant is clear and transparent, and remove an appropriate amount of the supernatant to obtain a concentrated protein slurry; (5) Mix the concentrated protein slurry and an alkaline solution, and stir for 1 to 5 minutes when the temperature of the obtained mixture is below 15 °C; (6) Filtration: Filter the stirred mixture in step (5) to obtain a corn protein slurry; (7) Optional drying.

7. The method according to claim 6, wherein The method has one or more of the following characteristics: The pH of the alkaline solution is 9 to 12, preferably 9 to 11 or 9.5 to 10.5; The alkaline solution is a sodium hydroxide solution; The mixing mass ratio of the corn protein slurry to the alkaline solution is 1:(0.5 to 3), preferably 1:(0.5 to 1.5); and The pH of the mixture is 9 to 12, preferably 9 to 11 or 9.5 to 10.5; The alkaline solution used in step (5) is from the alkaline solution separated from the corn after cleaning in step (1); optionally, the alkaline solution obtained in step (1) is concentrated and then used in step (5).

8. The corn protein slurry prepared by the method according to any one of claims 1-7, or the corn protein powder obtained by drying the corn protein slurry, or the feed containing the corn protein slurry or the corn protein powder; Preferably, in the corn protein powder, the zearalenone content is less than or equal to 1000 ppb, preferably less than or equal to 700 ppb, and more preferably less than or equal to 450 ppb; Preferably, in the corn protein powder, the total content of essential amino acids is greater than or equal to 20%, preferably greater than or equal to 23%, and more preferably greater than or equal to 25%; More preferably, in the corn protein powder, the aflatoxin B1 content is less than or equal to 6.5 ppb, preferably less than or equal to 6.3 ppb, and more preferably less than or equal to 6.0 ppb.

9. Use of a method for low-temperature alkaline filtration treatment of corn protein slurry in increasing the content of essential amino acids in corn protein powder and / or reducing zearalenone in corn protein powder, characterized in that, The low temperature is not higher than 15 °C, and the alkalinity is such that the pH of the corn protein slurry is 9 to 12; Preferably, the low temperature is 2 to 12 °C, more preferably 2 to 10 °C, more preferably 2 to 8 °C, and more preferably 4 to 8 °C; Preferably, the alkalinity is such that the pH of the corn protein slurry is 9 to 11 or 9.5 to 10.5; Preferably, the application further includes reducing aflatoxin in the corn protein powder, wherein the corn protein slurry is the corn protein slurry prepared from alkali-washed corn.

10. The application of the corn protein slurry or the corn protein powder according to claim 8 in the preparation of feed.

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