Processing method of enzymolysis corn protein powder with high protein content

Abstract

The invention discloses a high-protein-content enzymolysis corn protein powder processing method which comprises the following steps: S1, pretreatment: pretreating corn protein powder to obtain low-starch-content wet corn protein powder; s2, enzymolysis: starch in the corn protein powder is removed, the enzymolysis comprises I-segment enzymolysis and II-segment enzymolysis, one compound protease is firstly used for I-segment enzymolysis, and then the other compound protease is used for II-segment enzymolysis; and S3, spray drying: finally, spray drying is performed to generate the sectional type enzymolysis processing corn protein powder of the product, on one hand, the starch content in the corn protein powder is reduced, and the dosage limitation of the corn protein powder in aquatic feed is relieved; on the other hand, the corn protein powder is modified and added, most of prolamin and glutelin in the raw materials are changed into water-soluble protein and small peptide, and the animal utilization rate is greatly increased; in addition, the product can partially replace fish meal, so that feed resources are expanded, dependence on the fish meal is reduced, and the cost of an aquatic feed formula is also reduced.

Description

Technical Field

[0001] The invention belongs to the field of biotechnology, and in particular relates to a method for processing enzymatically hydrolyzed corn gluten powder with high protein content. Background Art

[0002] Corn gluten meal is a by-product of corn kernels after starch is produced by the food industry or purified by the brewing industry. It has a protein content of 60% to 70% and is rich in protein nutrients. Its metabolizable energy is higher than that of corn, and its total amino acid content is higher than that of soybean meal and fish meal. It has a special taste and color, obvious resource advantages, and high feeding value. It is currently widely used in feed production as a protein supplement.

[0003] Although corn gluten meal has a high protein content, its main components are alcohol-soluble protein (68%) and gluten (22%). There is a large area of ​​α-helical structure in the alcohol-soluble protein molecule, which makes it very hydrophobic. Gluten is only soluble in alkaline aqueous solution. The water solubility of the two is poor, and the amino acids are unbalanced. In addition, there is about 14-20% starch in corn gluten meal. These starches are not only firmly combined with corn protein to form a layer-by-layer wrapped complex, resulting in a low degree of hydrolysis of enzymatic hydrolysis, but also limiting its application in high-end aquatic feed. Therefore, in order to improve the water solubility and protein content of corn gluten meal, appropriate treatment methods can be used to remove starch, denature protein, expose the groups inside the corn protein molecule to the surface of the protein molecule, increase the contact points between the enzyme and the protein, make it easier to be enzymatically hydrolyzed, and improve the degree of hydrolysis of enzymatic hydrolysis. The commonly used methods currently include alkali treatment, cooking treatment, and puffing treatment. Although these methods can improve the degree of hydrolysis of enzymatic hydrolysis to a certain extent, the yield of small peptides in its enzymatic hydrolysis products is low, the products are not easily digested and absorbed by animals, and the nutrient utilization rate is low, resulting in great waste.

[0004] Therefore, the present invention provides a method for processing enzymatically hydrolyzed corn gluten powder with high protein content. The produced enzymatically hydrolyzed corn gluten powder with high protein content can replace fish meal in aquatic feed. Summary of the invention

[0005] In view of the problems raised by the above background technology, the purpose of the present invention is to provide a method for processing high-protein enzymatic corn gluten meal, which can produce high-protein enzymatic corn gluten meal that can replace fish meal in aquatic feed.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for processing enzymatically hydrolyzed corn gluten powder with high protein content comprises the following steps:

[0008] S1: pretreatment, obtaining wet corn gluten meal with low starch content by pretreatment of corn gluten meal;

[0009] S2: enzymatic hydrolysis, used to remove starch from corn gluten powder, the enzymatic hydrolysis includes stage I enzymatic hydrolysis and stage II enzymatic hydrolysis, firstly using a composite protease to perform stage I enzymatic hydrolysis, and then using another composite protease to perform stage II enzymatic hydrolysis;

[0010] S3: spray drying, and finally the segmented enzymatic hydrolysis and processing of corn gluten powder to generate the product through spray drying.

[0011] It is further defined that the S1 pretreatment step includes enzymatic hydrolysis, washing and centrifugation of corn gluten meal.

[0012] It is further defined that the enzymatic hydrolysis in S2 uses α-amylase, a small amount of pullulanase and saccharifying enzyme, the α-amylase added in an amount of 50-100 U / g, the pullulanase added in an amount of 20-30 U / g, the saccharifying enzyme added in an amount of 30-50 U / g, the pH is adjusted to 5.0-6.0 by adding 0.8-1.0% sodium hydroxide, the solid-liquid ratio during enzymatic hydrolysis is 1:5-8, the enzymatic hydrolysis temperature is 55-65°C, and the enzymatic hydrolysis time is 6-8h.

[0013] It is further defined that the product after enzymatic hydrolysis in the S2 is filtered or centrifuged to remove the supernatant, and then 10-20 times the amount of water is added to the precipitate, soaking and washing, the soaking time is 5-10 minutes, the water temperature is controlled at 60-80°C, and then filtered or centrifuged to obtain wet corn protein powder, wherein the crude protein content of the wet corn protein powder on a dry basis is ≥80%, and the moisture content is ≥60%.

[0014] It is further defined that the composite protease used in the enzymatic hydrolysis stage I in S2 is a compound of alkaline protease and neutral protease, the alkaline protease is added in an amount of 1000 to 2000 U / g, and the neutral protease is added in an amount of 500 to 1000 U / g.

[0015] It is further defined that the moisture content of the enzymatic hydrolysis material in stage I of S2 is 65-70%, the temperature is 55-60° C., the enzymatic hydrolysis time is 8-12 hours, and sodium hydroxide is added during the enzymatic hydrolysis process to control the pH value of the material at 7.0-8.0.

[0016] It is further defined that the composite protease used in the enzymatic hydrolysis of stage II in S2 is composed of Aspergillus oryzae solid-state fermentation enzyme preparation, acid protease and bromelain.

[0017] It is further defined that the neutral protease activity of the Aspergillus oryzae solid-state fermentation enzyme preparation is 1000-1500 U / g, the addition amount is 0.5-2.0%, the addition amount of acid protease is 1000-2000 U / g, and the addition amount of bromelain is 100-300 U / g.

[0018] It is further defined that the enzymatic hydrolysis temperature of stage II in S2 is 50-55° C., the enzymatic hydrolysis time is 12-16 hours, and the pH is not controlled during the enzymatic hydrolysis process.

[0019] It is further defined that the timing in S2 starts from the addition of the composite protease, and the total duration of the two stages of enzymatic hydrolysis is 18 to 24 hours.

[0020] Beneficial effects of the present invention:

[0021] The present invention provides a method for processing enzymatically hydrolyzed corn gluten powder with a high protein content. According to the above-mentioned method for processing enzymatically hydrolyzed corn gluten powder with a high protein content, the present invention first removes the starch part in the corn gluten powder by enzymatic hydrolysis, "concentrates" to obtain a high-protein corn gluten raw material, and then obtains an enzymatically hydrolyzed corn gluten powder with a high small peptide content and a crude protein content of ≥80% and an acid-soluble protein content of ≥60% through two steps of enzymatic hydrolysis. On the one hand, the present invention reduces the starch content in corn gluten powder and removes the restriction on its dosage in aquatic feed; on the other hand, the corn gluten powder is modified and increased in value, and most of the alcohol-soluble proteins and gluten in the raw material are converted into water-soluble proteins and small peptides, and the animal utilization rate is greatly improved. In summary, the high-protein enzymatic hydrolyzed corn gluten powder product of the present invention can partially replace fish meal, which helps to expand feed resources, reduce dependence on fish meal, and reduce the cost of aquatic feed formulations. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention can be further illustrated by the non-limiting examples given in the accompanying drawings;

[0023] Figure 1 It is a graph showing the proportions of various indicators of corn gluten powder at different enzymatic hydrolysis time periods in an embodiment of a method for processing enzymatic hydrolyzed corn gluten powder with high protein content of the present invention;

[0024] Figure 2 This is a diagram showing pH changes during enzymatic hydrolysis of corn gluten powder according to an embodiment of a method for processing enzymatic hydrolyzed corn gluten powder with high protein content of the present invention;

[0025] Figure 3 It is a graph showing the proportions of various indicators of corn gluten powder at different enzymatic hydrolysis time periods in an embodiment of a method for processing enzymatic hydrolyzed corn gluten powder with high protein content of the present invention;

[0026] Figure 4 This is a diagram showing pH changes during enzymatic hydrolysis of corn gluten powder according to an embodiment of a method for processing enzymatic hydrolyzed corn gluten powder with high protein content of the present invention;

[0027] Figure 5 The present invention is a schematic structural diagram of an embodiment of a method for processing enzymatically hydrolyzed corn gluten powder with high protein content. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0030] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] like Figure 1 As shown, a method for processing enzymatically hydrolyzed corn gluten powder with high protein content of the present invention comprises the following steps:

[0032] S1: pretreatment, obtaining wet corn gluten meal with low starch content by pretreatment of corn gluten meal;

[0033] S2: enzymatic hydrolysis, used to remove starch from corn gluten powder, the enzymatic hydrolysis includes stage I enzymatic hydrolysis and stage II enzymatic hydrolysis, firstly using a composite protease to perform stage I enzymatic hydrolysis, and then using another composite protease to perform stage II enzymatic hydrolysis;

[0034] S3: spray drying, and finally the segmented enzymatic hydrolysis and processing of corn gluten powder to generate the product through spray drying.

[0035] Preferably, the S1 pretreatment step comprises enzymatic hydrolysis, washing and centrifugation of corn gluten meal.

[0036] Preferably, the enzymatic hydrolysis in S2 uses α-amylase, and is compounded with a small amount of pullulanase and saccharifying enzyme, the α-amylase added in an amount of 50-100 U / g, the pullulanase added in an amount of 20-30 U / g, the saccharifying enzyme added in an amount of 30-50 U / g, and the pH is adjusted to 5.0-6.0 by adding 0.8-1.0% sodium hydroxide. The solid-liquid ratio during enzymatic hydrolysis is 1:5-8, the enzymatic hydrolysis temperature is 55-65°C, and the enzymatic hydrolysis time is 6-8h.

[0037] Preferably, the enzymatic hydrolysis product in S2 is filtered or centrifuged to remove the supernatant, and then 10-20 times the amount of water is added to the precipitate, and the precipitate is soaked and washed for 5 to 10 minutes, and the water temperature is controlled at 60 to 80° C., and then filtered or centrifuged to obtain wet corn gluten powder, wherein the crude protein content of the wet corn gluten powder on a dry basis is ≥80%, and the moisture content is ≥60%.

[0038] Preferably, the composite protease used in stage I enzymatic hydrolysis in S2 is compounded by alkaline protease and neutral protease, the alkaline protease is added in an amount of 1000-2000 U / g, and the neutral protease is added in an amount of 500-1000 U / g.

[0039] Preferably, the moisture content of the enzymatic hydrolysis material in stage I of S2 is 65-70%, the temperature is 55-60° C., the enzymatic hydrolysis time is 8-12 h, and sodium hydroxide is added during the enzymatic hydrolysis process to control the pH of the material at 7.0-8.0.

[0040] Preferably, the composite protease used in the stage II enzymatic hydrolysis in S2 is composed of Aspergillus oryzae solid-state fermentation enzyme preparation, acid protease and bromelain.

[0041] Preferably, the neutral protease activity of the Aspergillus oryzae solid-state fermentation enzyme preparation is 1000-1500 U / g, the addition amount is 0.5-2.0%, the addition amount of acid protease is 1000-2000 U / g, and the addition amount of bromelain is 100-300 U / g.

[0042] Preferably, the enzymatic hydrolysis temperature of stage II in S2 is 50-55° C., the enzymatic hydrolysis time is 12-16 h, and the pH is not controlled during the enzymatic hydrolysis process.

[0043] Preferably, the timing in S2 starts from the addition of the composite protease, and the total duration of the two stages of enzymatic hydrolysis is 18 to 24 hours.

[0044] Example 1

[0045] Small-scale experiment on high-protein enzymatic corn gluten meal 1

[0046] 1. Processing method

[0047] (1) Corn gluten meal pretreatment

[0048] Take 10kg corn gluten powder, add 100U / g (dry basis, the same below) of α-amylase, 30U / g of pullulanase, 20U / g of saccharifying enzyme, add 0.8% sodium hydroxide to adjust the pH of the solution to 5.0, add 80kg of water, control the enzymolysis temperature at 60°C, and the enzymolysis time is 8h. After enzymolysis, centrifuge to remove the supernatant, add 200kg of water to the precipitate, soak and wash, the soaking time is 10min, control the water temperature at 68-70°C, and obtain wet corn gluten powder after centrifugation.

[0049] (2) Stage I enzymatic hydrolysis

[0050] The pretreated wet corn protein powder was subjected to pH-controlled enzymatic hydrolysis using a composite protease, wherein the composite protease included alkaline protease and neutral protease, wherein the addition amount of alkaline protease was 1500U / g, the addition amount of neutral protease was 1000U / g, and the moisture content of the enzymatic hydrolysis material was 65%. The enzymatic hydrolysis was performed at 60°C for 10 hours, and during the enzymatic hydrolysis process, 0.8-1.0% sodium hydroxide solution was added to control the pH of the material at about 7.0.

[0051] (3) Stage II enzymatic hydrolysis

[0052] The second enzymolysis was performed using a composite protease composed of Aspergillus oryzae solid fermentation enzyme preparation, acid protease and bromelain. The addition amount of Aspergillus oryzae (neutral protease activity 1000U / g) was 1.5%, the addition amount of acid protease was 1000U / g, and the addition amount of bromelain was 200U / g. The enzymolysis was performed at 55°C for 14h, and the pH was not controlled during the enzymolysis process.

[0053] (4) Spray drying

[0054] The spray drying process starts from the first addition of the composite protease, and the total duration of the two enzymatic hydrolysis stages is 24 hours. The material after enzymatic hydrolysis is directly spray dried. The content of acid-soluble protein, crude protein, starch, crude ash, crude fiber and other nutrients in corn protein raw materials and enzymatically hydrolyzed corn protein is determined.

[0055] Small-scale experiment on high-protein enzymatic corn gluten powder 2

[0056] 1. Processing method

[0057] (1) Corn gluten meal pretreatment

[0058] Take 10kg corn gluten powder, add 50U / g α-amylase (dry basis, the same below), 20U / g pullulanase, 50U / g saccharifying enzyme, add 1.0% sodium hydroxide solution to adjust the pH to 6.0, control the temperature at 60°C, and the enzymolysis time is 8h. After enzymolysis, centrifuge to remove the supernatant, add 100kg water to the precipitate, soak and wash, soak for 10min, control the water temperature at 70°C, and obtain wet corn gluten powder after centrifugation.

[0059] (2) Stage I enzymatic hydrolysis

[0060] The pretreated wet corn protein powder was subjected to pH-controlled enzymatic hydrolysis using a composite protease, wherein the composite protease included alkaline protease and neutral protease, wherein the addition amount of alkaline protease was 1500U / g, the addition amount of neutral protease was 1000U / g, and the moisture content of the enzymatic hydrolysis material was 65%. The enzymatic hydrolysis was performed at 60°C for 10 hours, and during the enzymatic hydrolysis process, 0.8-1.0% sodium hydroxide solution was added to control the pH of the material at about 7.0.

[0061] (3) Stage II enzymatic hydrolysis

[0062] The second enzymolysis was performed using a composite protease composed of Aspergillus oryzae solid fermentation enzyme preparation, acid protease and bromelain. The addition amount of Aspergillus oryzae (neutral protease activity 1000U / g) was 1.5%, the addition amount of acid protease was 1500U / g, and the addition amount of bromelain was 200U / g. The enzymolysis was performed at 55°C for 14h, and the pH was not controlled during the enzymolysis process.

[0063] (4) Spray drying

[0064] The spray drying process starts from the first addition of the composite protease. The total duration of the two enzymatic hydrolysis stages is 24 hours. The material after enzymatic hydrolysis is directly spray dried. The content of acid-soluble protein, crude protein, starch, crude ash, crude fiber and other nutrients in corn protein raw materials and high-protein hydrolyzed corn protein powder was determined.

[0065] 2. Experimental results

[0066] Table 1 Physical and chemical indicators of nutritional components of corn gluten meal before and after small-scale enzymatic hydrolysis and fermentation

[0067]

[0068]

[0069] As shown in Table 1, in small test 1, after the corn gluten meal raw material was enzymatically processed by this process, the crude protein content increased from the original 63.15% to 81.76%; the acid-soluble protein content increased from 2.07% of the raw material to 62.95%, an increase of about 30 times; the water-soluble protein content increased from 2.45% of the raw material to 76.25%, an increase of about 30 times; the starch content decreased from 17.96% of the raw material to 2.56% of the product; and the pepsin digestibility increased from 68.05% of the raw material to 96.72%, an increase of 28.67%.

[0070] The results of small-scale experiment 2 were similar to those of small-scale experiment 1. After enzymatic hydrolysis, the crude protein content of the raw material increased from 63.93% to 82.03%; the acid-soluble protein content increased from 2.02% to 61.58%; the water-soluble protein content increased from 2.51% to 76.84%; the starch content decreased from 18.48% to 2.09%; and the pepsin digestibility increased to 97.79% compared with 67.75% of the raw material.

[0071] like Figure 1 The results are shown for corn gluten meal samples taken at different enzymatic hydrolysis time points, in which the digestibility of acid-soluble protein, water-soluble protein and pepsin has been greatly improved, while the crude protein content is almost unaffected.

[0072] like Figure 2 The figure shows the pH changes of corn gluten meal at different time periods during the enzymatic hydrolysis process. During the first stage of enzymatic hydrolysis, the pH value of the material rapidly drops from the initial 10.2 to about 7.0 after 6 hours of enzymatic hydrolysis. During the second stage of enzymatic hydrolysis, the pH value of the material slowly drops to about 6.0 after 24 hours of enzymatic hydrolysis.

[0073] The above results indicate that the processing method of high-protein enzymatic corn gluten powder effectively reduces the starch content in corn gluten powder, significantly increases the content of water-soluble and acid-soluble proteins, and greatly improves the digestibility and utilization rate of corn gluten powder.

[0074] Example 2

[0075] Small-scale experiment on high-protein enzymatic corn gluten meal

[0076] 1. Experimental Methods

[0077] (1) Corn gluten meal pretreatment

[0078] Take 500 kg of corn gluten powder, add 50 U / g of α-amylase (dry basis, the same below), 20 U / g of pullulanase, and 50 U / g of saccharifying enzyme, add 1.0% sodium hydroxide solution to adjust the pH to 6.0, control the temperature at 60°C, and the enzymolysis time is 8 hours. After enzymolysis, centrifuge to remove the supernatant, add 7500 kg of water to the precipitate, soak and wash, soak for 10 minutes, control the water temperature at 70°C, and obtain wet corn gluten powder after centrifugation.

[0079] (2) Stage I enzymatic hydrolysis

[0080] The pretreated wet corn protein powder was enzymatically hydrolyzed with a composite protease, which included alkaline protease and neutral protease, wherein the addition amount of alkaline protease was 1500U / g, the addition amount of neutral protease was 1000U / g, and the moisture content of the enzymatic material was 65%. The enzymatic hydrolysis was carried out at 60°C for 10 hours, and sodium hydroxide solution was added during the enzymatic hydrolysis process to control the pH of the material between 7.0 and 7.5.

[0081] (3) Stage II enzymatic hydrolysis

[0082] The second enzymolysis was performed using a composite protease composed of Aspergillus oryzae solid fermentation enzyme preparation, acid protease and bromelain. The addition amount of Aspergillus oryzae (neutral protease activity 1000U / g) was 1.5%, the addition amount of acid protease was 1000U / g, and the addition amount of bromelain was 200U / g. The enzymolysis was performed at 55°C for 14h, and the pH was not controlled during the enzymolysis process.

[0083] (4) Spray drying

[0084] The spray drying process starts from the first addition of the composite protease, and the total duration of the two enzymatic hydrolysis stages is 24 hours. The material after enzymatic hydrolysis is directly spray dried. The content of acid-soluble protein, crude protein, starch, crude ash, crude fiber and other nutrients in corn protein raw materials and enzymatically hydrolyzed corn protein is determined.

[0085] 1. Experimental results

[0086] Table 2 Physical and chemical indicators of nutritional components of corn gluten meal before and after pilot enzymatic fermentation

[0087]

[0088]

[0089] As shown in Table 2, after the corn gluten meal was hydrolyzed by this process, the acid-soluble protein content increased to 60.43%, which was about 30 times higher than the raw material content of 2.07%, the crude protein content increased from 63.15% of the raw material to 82.16%, the water-soluble protein content increased from 2.45% to 76.84%, which was about 30 times higher than the raw material content, and the pepsin digestibility increased by 28.05% to 96.13% compared with the raw material. The results are similar to those in Example 1, indicating that the enzymatic hydrolysis process is relatively stable.

[0090] Figure 3 and Figure 4 These are the measurement results of corn gluten meal samples taken at different enzymatic hydrolysis time points, and their changing trends are similar to those in Example 1.

[0091] Example 3

[0092] Effects of different proportions of high-protein proteolytic corn gluten meal replacing corn gluten meal on growth performance and antioxidant indexes of yellow-feathered laying hens

[0093] 1. Materials

[0094] 300 healthy one-day-old yellow-feathered laying hens were selected and divided into three treatments, with 100 chicks in each treatment. The chicks were reared in a free-range manner with rice husks spread on the ground, 24-hour light, free access to food and water, and vaccinated according to the normal immunization procedure. The experimental period was 21 days.

[0095] CK: uses corn-soybean meal as the main protein raw material, and the formula contains 10% corn gluten meal;

[0096] M1: high protein hydrolyzed corn gluten meal replaces 3% corn gluten meal;

[0097] M2: Highly enzymatically hydrolyzed corn gluten meal replaces 6% corn gluten meal.

[0098] 2. Sample Preparation

[0099] Highly proteolytic corn protein powder prepared in Example 2

[0100] 3. Determination indicators and methods

[0101] The feed intake of each replicate chick was recorded daily, and the fasting body weight was measured on the 1st, 11th, and 21st days for calculating the average daily gain (ADG), average daily feed intake (ADFI), and feed / meat ratio (F / G).

[0102] The levels of superoxide dismutase (SOD), total antioxidant capacity (T-AOC), catalase (CAT) and malondialdehyde (MDA) were determined by enzyme-linked immunosorbent assay.

[0103] 4.Basic feed formula and ingredients

[0104] The basic feed formula is shown in Table 3.

[0105] Table 3 Basic feed formula and ingredients (%)

[0106]

[0107]

[0108] 5. Results and Analysis

[0109] (1) Effect of high protein hydrolyzed corn gluten meal replacing corn gluten meal on the growth performance of yellow-feathered laying hens

[0110] As shown in Table 4, at the 0-11d, 12-21d, and 0-21d stages, the average daily weight gain of the chicks in the M1 and M2 groups was higher than that of the control group. At the 0-21d stage, the average daily weight gain of the M1 and M2 treatment groups was increased by 3.44% and 3.57% respectively compared with the CK group, which was significantly different. The average daily feed intake and feed-to-meat ratio of the M1 and M2 treatment groups in the three stages were not significantly different from those of the CK group, indicating that the high proteolytic corn gluten meal of the present invention can replace 3% and 6% of the corn gluten meal in the yellow-feathered laying hen feed, and can increase the average daily weight gain of the chicks without affecting the average daily feed intake and feed-to-meat ratio.

[0111] As shown in Table 5, superoxide dismutase, total antioxidant capacity and catalase in the M1 and M2 treatment groups were improved compared with the CK group, and the catalase content was significantly increased. The M1 and M2 treatment groups increased by 1.34% and 5.47% respectively compared with the CK group. The malondialdehyde content in the M1 and M2 treatment groups was significantly reduced compared with the CK group, which was reduced by 1.30% and 1.47% respectively. The results showed that high proteolytic corn protein powder can improve the serum antioxidant capacity of yellow-feathered laying hens and effectively reduce the formation of lipid peroxides in the body.

[0112] Table 4 Effects of different proportions of high-protein enzymatic hydrolyzed corn gluten meal replacing corn gluten meal on the growth performance of yellow-feathered laying hens

[0113]

[0114]

[0115] Note: Significant differences among groups (p=0.05) are indicated by a and b, and no significant differences are indicated if not indicated, the same below.

[0116] Table 5 Effects of different proportions of high-protein protein hydrolyzed corn gluten meal replacing corn gluten meal on antioxidant indexes of yellow-feathered laying hens

[0117]

[0118] Example 4

[0119] Effects of different proportions of high-protein corn gluten meal replacing fish meal on the growth performance of Penaeus monodon

[0120] 1. Materials and Sample Preparation

[0121] 900 healthy and vigorous Penaeus monodon shrimps weighing about 5 g were selected and divided into three treatments (CK, T1, T2). Three cages were set up for each treatment, and 100 Penaeus monodon shrimps were raised in each cage. The content of fish meal and high-protein corn gluten meal added to each treatment was as follows.

[0122] CK: uses fish meal as the main protein raw material;

[0123] T1: high protein hydrolyzed corn gluten meal replaces 5% fish meal;

[0124] T2: Highly enzymatically hydrolyzed corn gluten meal replaces 10% of fish meal.

[0125] 2. Preparation of high protein hydrolyzed corn gluten powder

[0126] The highly proteolytic corn protein powder prepared in Example 2 was used.

[0127] 3. Determination indicators and methods

[0128] The number of dead Penaeus monodon in each cage was cleaned and recorded every day, and the survival rate was calculated. The weight of each shrimp was measured, and the weight gain rate, specific growth rate and feed efficiency were calculated.

[0129] 4.Basic feed formula and ingredients

[0130] The basic feed formula is shown in Table 6.

[0131] Table 6 Formula and composition of basic feed for Penaeus monodon (%)

[0132]

[0133] 5. Results and Analysis

[0134] The effects of replacing different proportions of fish meal with high protein hydrolyzed corn gluten meal on the survival rate and growth indicators of Penaeus monodon are shown in Table 7.

[0135] Table 7 Survival rate and growth index of Penaeus monodon in each group

[0136]

[0137] As shown in Table 7, the survival rates of Penaeus monodon in the CK group, T1 and T2 treatment groups were 99%, 98.0% and 98.5% respectively, and there was no significant difference in survival rate among the groups. The weight gain rate and specific growth rate of the T2 treatment group were slightly lower than those of the CK group, but there was no significant difference. There was no significant difference in feed coefficient between the T1 and T2 treatment groups compared with the CK group. This shows that replacing 5% or 10% of fish meal with the high proteolytic corn protein powder of the present invention has no significant effect on the growth index of Penaeus monodon, and this product can be used to replace part of fish meal in feeding to reduce feed costs.

[0138] Example 5

[0139] Effects of different proportions of high-protein proteolytic corn gluten meal replacing fish meal on growth performance of large yellow croaker

[0140] 1. Materials

[0141] Healthy yellow croakers with similar body weight were selected and divided into three treatments (CK, T1, T2). Three cages were set up in each treatment, and 50 yellow croakers were raised in each cage. The content of fish meal and highly enzymatically hydrolyzed corn protein added to each treatment was as follows.

[0142] CK: uses fish meal as the main protein raw material, and the formula contains 35% fish meal;

[0143] T1: high protein hydrolyzed corn gluten meal replaces 5% fish meal;

[0144] T2: Highly enzymatically hydrolyzed corn gluten meal replaces 10% of fish meal.

[0145] 2. Preparation of high protein hydrolyzed corn gluten powder

[0146] The high protein hydrolyzed corn protein meal prepared in Example 2.

[0147] 3. Determination indicators and methods

[0148] The number of dead large yellow croakers in each cage was cleaned and recorded every day, and the survival rate was calculated. The weight of each fish was measured, and the weight gain rate, specific growth rate and feed efficiency were calculated.

[0149] 4.Basic feed formula and ingredients

[0150] The basic feed formula is shown in Table 7.

[0151] Table 7 Formula and composition of basic feed for large yellow croaker (%)

[0152]

[0153]

[0154] 5. Results and Analysis

[0155] The effects of replacing different proportions of fish meal with high protein hydrolyzed corn protein on the survival rate and growth indicators of large yellow croaker are shown in Table 8.

[0156] Table 8 Survival rate and growth index of large yellow croaker in each group

[0157]

[0158] As shown in Table 8, in the conventional large yellow croaker feed formula, replacing 5% or 10% of fish meal with the high protein hydrolyzed corn protein powder of the present invention has no significant difference in the survival rate, weight gain rate, specific growth rate and feed efficiency of large yellow croaker, indicating that the product of the present invention can replace part of the fish meal in the use of large yellow croaker feed, reduce the feed cost, and has no significant effect on the growth indicators of large yellow croaker.

[0159] In summary, the present invention reduces the starch content in corn gluten meal on the one hand, thereby removing the restriction on its usage in aquatic feed; on the other hand, the corn gluten meal is modified and increased in value, and most of the alcohol-soluble proteins and gluten in the raw materials are converted into water-soluble proteins and small peptides, thereby greatly improving the animal utilization rate; in addition, the high-protein hydrolyzed corn gluten meal product of the present invention can partially replace fish meal, thereby helping to expand feed resources, reduce dependence on fish meal, and reduce the cost of aquatic feed formulations.

[0160] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A method for processing enzymatically hydrolyzed corn gluten powder with high protein content, characterized in that: The steps include: S1: pretreatment, obtaining wet corn gluten meal with low starch content by pretreatment of corn gluten meal; S2: enzymatic hydrolysis, used to remove starch from corn gluten powder, the enzymatic hydrolysis includes stage I enzymatic hydrolysis and stage II enzymatic hydrolysis, firstly using a composite protease to perform stage I enzymatic hydrolysis, and then using another composite protease to perform stage II enzymatic hydrolysis; S3: spray drying, and finally the segmented enzymatic hydrolysis and processing of corn gluten powder to generate the product through spray drying.

2. A method for processing enzymatically hydrolyzed corn gluten powder with high protein content according to claim 1, characterized in that: The S1 pretreatment step includes enzymatic hydrolysis, washing and centrifugation of corn gluten powder.

3. The method for processing enzymatically hydrolyzed corn gluten powder with high protein content according to claim 1, characterized in that: The enzymatic hydrolysis in S2 uses α-amylase, a small amount of pullulanase and saccharifying enzyme, the α-amylase added in an amount of 50-100 U / g, the pullulanase added in an amount of 20-30 U / g, the saccharifying enzyme added in an amount of 30-50 U / g, and the pH is adjusted to 5.0-6.0 by adding 0.8-1.0% sodium hydroxide. The solid-liquid ratio during enzymatic hydrolysis is 1:5-8, the enzymatic hydrolysis temperature is 55-65°C, and the enzymatic hydrolysis time is 6-8h.

4. The method for processing enzymatically hydrolyzed corn gluten powder with high protein content according to claim 1, characterized in that: The enzymatic hydrolysis product in S2 is filtered or centrifuged to remove the supernatant, and then 10-20 times of water is added to the precipitate, soaking and washing, the soaking time is 5-10 minutes, the water temperature is controlled at 60-80° C., and then filtered or centrifuged to obtain wet corn gluten powder, wherein the crude protein content of the wet corn gluten powder on a dry basis is ≥80%, and the moisture content is ≥60%.

5. The method for processing enzymatically hydrolyzed corn gluten powder with high protein content according to claim 1, characterized in that: The composite protease used in the enzymatic hydrolysis of stage I in S2 is compounded by alkaline protease and neutral protease, the alkaline protease addition amount is 1000-2000U / g, and the neutral protease addition amount is 500-1000U / g.

6. The method for processing enzymatically hydrolyzed corn gluten powder with high protein content according to claim 1, characterized in that: The material of stage I enzymolysis in S2 has a moisture content of 65-70%, a temperature of 55-60° C., and an enzymolysis time of 8-12 hours. During the enzymolysis process, sodium hydroxide is added to control the pH value of the material at 7.0-8.

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7. The method for processing enzymatically hydrolyzed corn gluten powder with high protein content according to claim 1, characterized in that: The composite protease used in the stage II enzymatic hydrolysis in S2 is composed of Aspergillus oryzae solid-state fermentation enzyme preparation, acid protease and bromelain.

8. The method for processing enzymatically hydrolyzed corn gluten powder with high protein content according to claim 7, characterized in that: The neutral protease activity of the Aspergillus oryzae solid-state fermentation enzyme preparation is 1000-1500 U / g, the addition amount is 0.5-2.0%, the addition amount of the acid protease is 1000-2000 U / g, and the addition amount of the bromelain is 100-300 U / g.

9. The method for processing enzymatically hydrolyzed corn gluten powder with high protein content according to claim 1, characterized in that: The enzymatic hydrolysis temperature of stage II in S2 is 50-55° C., the enzymatic hydrolysis time is 12-16 hours, and the pH is not controlled during the enzymatic hydrolysis process.

10. The method for processing enzymatically hydrolyzed corn gluten powder with high protein content according to claim 1, characterized in that: In S2, the timing starts from the addition of the composite protease, and the total duration of the two stages of enzymatic hydrolysis is 18 to 24 hours.

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