Production method of corn steep liquor fermented protein and corn steep liquor fermented protein

Abstract

The invention belongs to the technical field of feed, and particularly relates to a production method of corn steep liquor fermented protein and the corn steep liquor fermented protein.The production method comprises the steps that corn steep liquor is sterilized, and the sterilized corn steep liquor is obtained; inoculating a leavening agent into the sterilized corn steep liquor, and carrying out aerobic fermentation to obtain corn steep liquor fermentation liquor; the corn steep liquor fermentation liquor is subjected to an air floatation method to obtain an air floatation liquid and fermentation protein mixture; carrying out cation removal on the air floatation liquid to obtain cation precipitate and supernate; mixing the supernate and the fermented protein mixture, and drying to obtain corn steep liquor fermented protein; compared with corn steep liquor dry powder obtained by directly drying corn steep liquor, the corn steep liquor fermented protein obtained by the invention has the advantages that toxin contained in the corn steep liquor fermented protein is reduced, the caking problem can be effectively solved, and the ash content is reduced.

Description

Technical Field

[0001] The present application relates to the field of feed technology, and more specifically, to a production method of corn steep liquor fermented protein and corn steep liquor fermented protein. Background Art

[0002] The information disclosed in this background section is intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] At present, corn slurry is further dried into corn slurry powder during the production process. There are some problems with corn slurry powder that limit its application, including: 1) Toxin problem. Since the raw material corn slurry contains high concentrations of aflatoxin, vomitoxin, fumonisin, hertoxin and zearalenone, the corn slurry powder has excessive toxins, affecting its market value; 2) Agglomeration problem. When corn slurry powder is exposed to the air, it absorbs water and dries. Affecting the subsequent addition and use in feed and other products; 3) High ash content. The ash content of corn slurry powder is about 15%, which affects the palatability of feed and other problems, limiting its application scope and addition amount. Summary of the invention

[0004] The present application is provided to solve the above-mentioned defects existing in the prior art. A production method of corn slurry fermented protein and corn slurry fermented protein are needed, and the obtained corn slurry fermented protein has lower toxin and ash content than corn slurry dry powder obtained by directly drying corn slurry, and can also effectively solve the caking problem when placed in the air.

[0005] In a first aspect of the present application, a method for producing corn slurry fermented protein is provided, the method comprising: sterilizing corn slurry to obtain sterilized corn slurry; inoculating a starter into the sterilized corn slurry and performing aerobic fermentation to obtain corn slurry fermented liquid; subjecting the corn slurry fermented liquid to a flotation method to obtain a mixture of a flotation liquid and fermented protein; removing cations from the flotation liquid to obtain a cation precipitate and a supernatant; and mixing the supernatant and the fermented protein mixture and drying to obtain corn slurry fermented protein.

[0006] In a second aspect of the present application, a corn steep liquor fermented protein is provided which is obtained by the production method described in any embodiment of the present application.

[0007] The production method of corn slurry fermented protein and corn slurry fermented protein provided in each embodiment of the present application can effectively reduce the content of toxins such as aflatoxin, vomitoxin and zearalenone by inoculating a starter agent for aerobic fermentation; and the aerobic fermentation process carried out by the starter agent can remove lactic acid and residual sugar in the corn slurry, effectively solving the problem of finished product agglomeration; the cations in the flotation liquid are removed and then mixed with the fermented protein mixture, which can effectively reduce the ash content in the corn slurry fermented protein. Therefore, the obtained corn slurry fermented protein is more conducive to addition and use in subsequent feed and other products, and can also improve the palatability of the feed and improve its use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In the drawings, which are not necessarily drawn to scale, the same reference numerals may describe similar parts in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar parts. The accompanying drawings generally illustrate various embodiments by way of example and not limitation, and together with the specification and claims, are used to illustrate the embodiments applied for. When appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the present apparatus or method.

[0009] Figure 1 A state diagram of corn steep liquor fermentation after flotation according to Example 1 of the present application is shown; Figure 2 The state diagram of the flotation liquid after pH adjustment according to Example 1 of the present application is shown; Figure 3 A diagram showing the lactic acid fermentation consumption of the aerobic fermentation process according to Example 1 of the present application; Figure 4 A comparison chart of protein removal rates with and without the addition of PAM according to an embodiment of the present application is shown; Figure 5 A comparison chart of ash content in the supernatant at different pH values ​​according to an embodiment of the present application is shown; Figure 6 A state diagram showing a corn steep liquor fermented protein product according to different embodiments of the present application; Figure 7 A comparison chart of aflatoxin degradation rates according to the present application is shown; Figure 8 A comparative diagram of the degradation rate of zearalenone toxin according to the present application is shown. DETAILED DESCRIPTION

[0010] In order to enable those skilled in the art to better understand the technical solution of the present application, the present application is described in detail below in conjunction with the accompanying drawings and specific implementation examples. The embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific implementation examples, but are not intended to limit the present application.

[0011] The words "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.

[0012] According to an embodiment of the present application, a method for producing corn slurry fermented protein is provided, the production method comprising: sterilizing corn slurry to obtain sterilized corn slurry; inoculating a starter into the sterilized corn slurry and performing aerobic fermentation to obtain corn slurry fermentation liquid; subjecting the corn slurry fermentation liquid to a flotation method to obtain a mixture of a flotation liquid and fermented protein; removing cations from the flotation liquid to obtain a cation precipitate and a supernatant; and mixing the supernatant and the fermented protein mixture and drying to obtain corn slurry fermented protein.

[0013] After the sterilized corn slurry is inoculated with a fermentation agent, the corn slurry can effectively reduce the content of toxins such as aflatoxin, vomitoxin and zearalenone after fermentation compared to before fermentation, effectively solving the problem of high toxins. The increase in yeast protein further increases the protein content of the finished product. In addition, during the fermentation process, lactic acid and residual sugar in the corn slurry can be removed to prevent the corn slurry fermented protein from absorbing moisture and drying when exposed to the air, solving the problem of caking of the corn slurry fermented protein finished product.

[0014] After the corn steep liquor is subjected to air flotation, the protein is suspended in the air flotation liquid, and the precipitation of the air flotation liquid and the fermented protein mixture is separated. The air flotation liquid is subjected to cation removal to form a cation precipitate and a supernatant. The cation precipitate includes a lot of inorganic salt ash, such as calcium salt and magnesium salt. Through the process of cation removal, the inorganic salt in the corn steep liquor fermented protein can be removed, the ash content can be reduced, and the palatability of the feed can be improved. The supernatant and the fermented protein mixture are mixed and dried to obtain the final corn steep liquor fermented protein.

[0015] Therefore, the production method of the present application can produce corn steep liquor fermented protein with low toxin content, low ash content and no agglomeration after being placed in the air.

[0016] Corn steep liquor is prepared from corn through a corn soaking process. In some embodiments, the mass concentration of corn steep liquor is 5%-30%. It can also be obtained by diluting concentrated corn steep liquor.

[0017] In some embodiments, the sterilization treatment conditions are: temperature 110-120°C, time 10-20 min.

[0018] In some embodiments, the fermentation agent includes any one or more of yeast, genetically modified yeast, laccase, lipase, oxidase, protease, and cellulase, wherein the genetically modified yeast is a strain expressing any one or more of laccase, lipase, oxidase, protease, and cellulase. Yeast is inoculated into corn slurry, and during aerobic fermentation, yeast can consume lactic acid and residual sugar in corn slurry, effectively solving the problem of finished product agglomeration.

[0019] In some embodiments, the volume ratio of the inoculated yeast in the sterilized corn steep liquor is greater than or equal to 10%. The larger the inoculation ratio, the shorter the fermentation time of the corn steep liquor, and the smaller the inoculation ratio, the longer the fermentation time. It can be adjusted according to the needs of the site. Due to the consumption of lactic acid during the fermentation process, the pH will gradually increase. Generally, at about pH 8.0, the lactic acid has been exhausted, and it can be considered to terminate the fermentation.

[0020] In some embodiments, after sterilization and before inoculation of the fermentation agent, the pH of the corn steep liquor is adjusted to 4-6 and the temperature is adjusted to 25-35° C. The temperature is maintained at 25-35° C. during the fermentation process.

[0021] In some embodiments, the yeast or genetically modified yeast is first expanded before inoculation into the sterilized corn syrup. During the expansion culture, YPD medium is used for aerobic culture, and the culture conditions are: temperature 25-35°C. In some embodiments, the yeast may include Saccharomyces cerevisiae or Candida. In some embodiments, the YPD medium includes 1% by mass yeast extract, 2% by mass peptone, and 2% by mass glucose.

[0022] In some embodiments, the fermentation is stopped when the pH of the corn steep liquor reaches 8.0 during the aerobic fermentation of the inoculated starter.

[0023] In some embodiments, a demulsifier or a flocculant is added to the corn steep liquor during the flotation process; the mass of the demulsifier or the flocculant added is 0.001%-1% of the mass of the corn steep liquor.

[0024] In some embodiments, flotation is performed using an air flotation bed, and air is blown into the flotation process with a ventilation volume of 0.1-2 VVM.

[0025] In some embodiments, the cation removal of the aerosol comprises: adjusting the pH of the aerosol to 9-12 using an alkaline solution.

[0026] After the flotation liquid is subjected to cation removal, the obtained supernatant is mixed with the fermented protein mixture. Compared with the process without flotation and cation removal, the mass content of ash can be reduced by about 40%.

[0027] In some embodiments, the supernatant and the fermented protein mixture are mixed and then dried to obtain corn steep liquor fermented protein, comprising: concentrating the supernatant and the fermented protein mixture after mixing; and drying the concentrated mixture to obtain corn steep liquor fermented protein.

[0028] In some embodiments, bacterial protein is added to the concentrated mixture to obtain a protein mixture. In some embodiments, bacterial protein is a byproduct obtained in the production process of a fermentation enterprise. The bacterial protein can be the bacterial cells or protein-rich process liquid after fermentation in a fermentation enterprise, and its addition can improve the quality of corn steep liquor fermentation protein or solve the problem of bacterial cell treatment in a fermentation enterprise.

[0029] In some embodiments, the concentrated mixture is dried using a vibrating fluidized bed drying device or a spray drying device to obtain corn steep liquor fermented protein. In some embodiments, the hot air temperature of the spray drying is 100-200°C. According to an embodiment of the present application, a corn syrup fermented protein obtained by the production method described in any embodiment of the present application is also provided. The corn syrup fermented protein prepared by the present application has less ash content and less toxin content, and is not easy to clump after absorbing moisture in the air. The corn syrup fermented protein prepared by the present application can be used in agricultural fields such as animal husbandry.

[0030] Example 1 Saccharomyces cerevisiae was expanded and cultured. YPD medium was used to culture Saccharomyces cerevisiae and Candida aerobically, respectively, at a culture temperature of 30°C. The expansion culture process adopted the conventional fermentation expansion culture process, which included plate activation step, shake flask culture step and 5 L seed tank culture step. 1) First, the yeast was activated on a YPD solid plate and cultured in an incubator at 30°C for about 24 h. 2) Prepare YPD liquid culture medium, shake flask 500 mL with a liquid volume of 50 mL, sterilize and use an inoculation loop to take bacteria and inoculate 1 inoculation loop, then culture at 30°C in a shaker for about 24 h, with a shaker speed of 220 RPM. 3) Prepare a 5 L small fermentation tank with YPD culture medium for fermentation, with a culture volume of about 3L, 600RPM, aeration volume of 0.3-1VVM, and an inoculation volume ratio of 10%. Fermentation ended after 24 hours as seed liquid.

[0031] Example 2 (1) The corn slurry was sterilized at 115°C for 15 min. The sterilized corn slurry was cooled to 30°C and the pH was adjusted to 5.0 using liquid ammonia.

[0032] (2) The corn steep liquor obtained in step (1) was inoculated with 10% by volume of the Saccharomyces cerevisiae strain obtained in Example 1 for aerobic fermentation. When the pH of the corn steep liquor was 8.0, the aerobic fermentation was stopped to obtain a corn steep liquor.

[0033] (3) Add the corn syrup fermentation liquid obtained in step (2) to the flotation bed, and add polyacrylamide (PAM) cationic flocculant, the amount of polyacrylamide (PAM) cationic flocculant added is 0.1% of the mass of the corn syrup fermentation liquid, and blow air into the flotation bed at 0.5 VVM (cubic meters / minute) to obtain the following: Figure 1 In the state shown, the protein is suspended in the flotation liquid, and the fermented protein mixture and the flotation liquid can be obtained by separation.

[0034] (4) Liquid ammonia is added to the flotation liquid to make the pH of the flotation liquid reach 12, and a cationic precipitate and a supernatant are obtained, such as Figure 2 As shown, salt substances are precipitated (cation precipitation) at the bottom of the flotation liquid; (5) The supernatant obtained in step (4) and the fermented protein mixture obtained in step (3) are mixed, concentrated and spray-dried, and the hot air temperature of the spray drying is 150-160° C. to obtain a corn syrup fermented protein product, which is in powder form.

[0035] The lactic acid fermentation consumption in the aerobic fermentation process in step (2) is as follows: Figure 3 As shown, through Figure 3 It can be seen that during the fermentation process of 0-20 hours, the lactic acid is gradually consumed.

[0036] The difference from the above step (3) is that without adding polyacrylamide PAM cationic flocculant, the mass of protein suspended in the flotation liquid after the flotation process is 20% of the mass of protein in the corn syrup fermentation broth. In Example 2, polyacrylamide PAM cationic flocculant is added, and after the flotation process, the mass of protein suspended in the flotation liquid obtained is 90% of the mass of protein in the corn syrup fermentation broth. For example, Figure 4 Therefore, adding polyacrylamide (PAM) cationic flocculant can obtain nearly 100% protein, effectively separate the aerosol and protein, increase the protein yield, and also facilitate the subsequent cationic precipitation of the aerosol to remove ash.

[0037] The difference from Example 2 is that the amount of liquid ammonia added in step (4) is changed so that the pH of the flotation liquid after adjustment is 9, 10, and 11, and the mass fraction of ash in the obtained supernatant is as follows: Figure 5As shown, it can be obtained that the mass fraction of ash in the supernatant after cation precipitation corresponding to pH 9 is about 0.81%, the mass fraction of ash in the supernatant after cation precipitation corresponding to pH 10 is about 0.8%, the mass fraction of ash in the supernatant after cation precipitation corresponding to pH 11 is about 0.49%, and the mass fraction of ash in the supernatant after cation precipitation corresponding to pH 12 is about 0.31%. Figure 5 CK in the figure indicates that the mass fraction of ash in the flotation liquid is about 0.85% when no liquid ammonia is added in step (4). Therefore, by adjusting the pH, the ash content in the supernatant can be significantly reduced.

[0038] Example 3 Different from Example 2, a vibrating fluidized bed drying device is used for drying, and the hot air temperature is 120-130° C., and the corn steep liquor fermented protein is obtained in granular form.

[0039] In Example 3, the drying method and hot air temperature were changed compared with Example 2, and the state of the corn steep liquor fermented protein product obtained was different, such as Figure 6 As shown, the corn steep liquor fermented protein product of Example 3 is in granular form, and the corn steep liquor fermented protein product of Example 2 is in powder form.

[0040] Example 4 The difference from Example 2 is that in step (2), the Candida species is inoculated, and the corn steep liquor fermented protein is obtained in powder form.

[0041] Comparative Example 1 The difference from Example 2 is that in step (2), Bacillus coagulans ZC04 is inoculated, and aerobic fermentation is carried out for 20 hours to obtain corn steep liquor. The other steps are the same as those in Example 2.

[0042] The corn steep liquor fermented protein obtained in Example 2, Example 4 and Comparative Example 1 has a aflatoxin content compared to the corn steep liquor in step (1) of Example 2. The degradation rate of aflatoxin is as follows: Figure 7 As shown, the degradation rate of aflatoxin of the brewer's yeast in Example 2 reached 80%, the degradation rate of aflatoxin of the comparative example 1 reached 20%, and the degradation rate of aflatoxin of the candida in Example 4 reached 30%. This shows that the degradation rate of aflatoxin of brewer's yeast is the best.

[0043] The corn steep liquor fermented protein obtained in Example 2, Example 4 and Comparative Example 1 has a degradation rate of zearalenone toxin compared to the zearalenone toxin content in the corn steep liquor in step (1). Figure 8As shown, the degradation rate of aflatoxin of the brewer's yeast in Example 2 can reach 30%, the degradation rate of aflatoxin of the comparative example 1 can reach about 8%, and the degradation rate of aflatoxin of the candida in Example 4 can reach 10%. This shows that the degradation rate of aflatoxin of brewer's yeast is the best.

[0044] The corn steep liquor fermented protein products obtained in Examples 1 to 4 were placed in the air for 5 days, and it was found that the corn steep liquor fermented protein products of each Example absorbed moisture in the air, but no agglomeration occurred.

[0045] In addition, although exemplary embodiments have been described herein, the scope includes any and all embodiments based on the present application with equivalent elements, modifications, omissions, combinations (e.g., various embodiments intersecting schemes), adaptations or changes. The elements in the claims are to be interpreted broadly based on the language adopted in the claims, and are not limited to the examples described in this specification or during the practice of this application, and the examples are to be interpreted as non-exclusive. Therefore, this specification and examples are intended to be considered as examples only, and the true scope and spirit are indicated by the following claims and the full scope of their equivalents.

[0046] The above description is intended to be illustrative rather than restrictive. For example, the above examples (or one or more schemes thereof) may be used in combination with each other. For example, a person of ordinary skill in the art may use other embodiments when reading the above description. In addition, in the above-mentioned specific embodiments, various features may be grouped together to simplify the present application. This should not be interpreted as an intention that a feature of an application that does not require protection is necessary for any claim. On the contrary, the subject matter of the present application may be less than all the features of an embodiment of a particular application. Thus, the following claims are incorporated herein in the specific embodiments as examples or embodiments, wherein each claim is independently a separate embodiment, and it is considered that these embodiments may be combined with each other in various combinations or arrangements. The scope of the present invention should be determined with reference to the appended claims and the full scope of equivalent forms granted by these claims.

[0047] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present application, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A method for producing corn steep liquor fermented protein, characterized in that: The production method comprises: The corn steep liquor is sterilized to obtain the sterilized corn steep liquor; Inoculating a starter into the sterilized corn steep liquor and performing aerobic fermentation to obtain corn steep liquor; The corn steep liquor fermentation liquid is subjected to an air flotation method to obtain an air flotation liquid and a fermentation protein mixture; The flotation liquid is subjected to cation removal to obtain a cation precipitate and a supernatant; The supernatant and the fermented protein mixture are mixed and then dried to obtain corn steep liquor fermented protein.

2. The production method according to claim 1, characterized in that The fermentation agent includes any one or more of yeast, genetically modified yeast, laccase, lipase, oxidase, protease, and cellulase. The genetically modified yeast is a strain expressing any one or more of laccase, lipase, oxidase, protease, and cellulase.

3. The production method according to claim 2, characterized in that: The volume ratio of the inoculated yeast in the sterilized corn steep liquor is greater than or equal to 10%.

4. The production method according to claim 1, characterized in that After sterilization and before inoculation with the starter, the pH of the corn steep liquor was adjusted to 4-6.

5. The production method according to claim 1, characterized in that: During the flotation process, a demulsifier or a flocculant is added to the corn steep liquor; the mass of the demulsifier or the flocculant added is 0.001%-1% of the mass of the corn steep liquor.

6. The production method according to claim 1, characterized in that: The flotation was performed using an air flotation bed, during which air was introduced with a ventilation volume of 0.1-2 VVM.

7. The production method according to claim 1, characterized in that: The aerosol liquid is subjected to cation removal, including: using alkaline solution to adjust the pH of the aerosol liquid to 9-12.

8. The production method according to claim 1, characterized in that: The supernatant and the fermented protein mixture are mixed and then dried to obtain corn steep liquor fermented protein, which comprises: the supernatant and the fermented protein mixture are mixed and then concentrated; and the concentrated mixture is dried to obtain corn steep liquor fermented protein.

9. The production method according to claim 8, characterized in that: The mixture is dried by using a vibrating fluidized bed drying device or a spray drying device to obtain corn steep liquor fermented protein.

10. Corn steep liquor fermented protein obtained by the production method according to any one of claims 1 to 9.

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