Preparation method of soluble ovalbumin pearl polypeptide powder

Abstract

The invention relates to a preparation method of soluble ovalbumin pearl polypeptide powder, which comprises the following steps: 1) mixing egg white protein powder and pearl powder with water, and heating for pretreatment to obtain a pretreated ovalbumin pearl powder solution; 2) cooling the ovalbumin pearl powder solution pretreated in the step 1), and adding keratinase and neutral protease for primary enzymolysis to obtain an ovalbumin pearl powder solution subjected to primary enzymolysis; (3) adding alkaline protease into the ovalbumin pearl powder solution subjected to primary enzymolysis in the step (2) for secondary enzymolysis to obtain an ovalbumin pearl powder solution subjected to secondary enzymolysis; and 4) heating the ovalbumin pearl powder solution subjected to secondary enzymolysis in the step 3), slowly adding lactic acid for acidolysis, cooling, supplementing water in the cooling process, filtering, and freeze-drying feed liquid to obtain the ovalbumin pearl powder. The preparation method provided by the invention greatly improves the content of small-molecule polypeptide and amino acid in the soluble pearl powder.

Description

Technical Field

[0001] The invention relates to a method for preparing soluble egg white protein pearl polypeptide powder. Background Art

[0002] Pearl powder is a precious Chinese medicinal material with the effects of calming the nerves and relieving shock, clearing away heat and detoxifying, improving eyesight and removing cataracts, astringing and promoting tissue regeneration, preserving youth, making the skin shiny and white, and moisturizing the skin.

[0003] Ovalbumin has important physiological functions. It can regulate the nervous system and immune system in the body, enhance physical strength, boost spirits, and restore fatigue caused by excessive work.

[0004] However, the main components of pearl powder, calcium carbonate and keratin, are difficult to dissolve in water and are not easily absorbed by the human body. Pearl powder is processed into water-soluble pearl powder and processed together with egg white protein, so that its insoluble components, calcium carbonate and keratin, become active calcium and trace elements that are soluble in water and can be directly absorbed and utilized by the human body, and the content of amino acids and polypeptides is greatly increased. Because most of its nutrients can be directly absorbed by the human body, it is mostly used for internal treatment and health care, by regulating the endocrine system of the human body, promoting metabolism and enhancing the body's immunity, preventing cardiovascular diseases, and improving heart function.

[0005] The existing pearl powder processing methods all use acid hydrolysis, which uses acid hydrolysis and neutral protease to treat pearl powder. Most of the keratin in it is not converted into soluble protein or polypeptide, and it is difficult to be fully utilized. In addition, acid hydrolysis first has a great interference with the subsequent addition of protease, and the content of polypeptide and amino acid in pearl powder after single processing is very low.

[0006] Therefore, it is necessary to provide a method for significantly increasing the polypeptide and amino acid content of soluble pearl powder. Summary of the invention

[0007] In order to overcome the defects of the prior art, the present invention provides a method for preparing soluble egg white protein pearl polypeptide powder. The method of the present invention greatly increases the polypeptide and amino acid content of the soluble pearl powder, is easy to operate, does not require pre-enzymatic hydrolysis of egg white protein, reduces processing steps, shortens processing time, and saves costs.

[0008] The technical solution of the present invention is as follows:

[0009] The present invention provides a method for preparing soluble egg white protein pearl polypeptide powder, which comprises the following steps:

[0010] 1) mixing egg white protein powder and pearl powder with water, and heating for pretreatment to obtain a pretreated egg white protein pearl powder solution;

[0011] 2) cooling the egg white pearl powder solution pretreated in step 1), and then adding keratinase and neutral protease to perform enzymolysis to obtain an enzymolyzed egg white pearl powder solution;

[0012] 3) adding alkaline protease to the egg white pearl powder solution obtained by the primary enzymatic hydrolysis in step 2) to perform secondary enzymatic hydrolysis to obtain a secondary enzymatic hydrolyzed egg white pearl powder solution;

[0013] 4) heating the egg white protein pearl powder solution obtained by secondary enzymatic hydrolysis in step 3), slowly adding lactic acid for acid hydrolysis, cooling, adding water during the cooling process, filtering, and freeze-drying the solution to obtain the product.

[0014] Preferably, the mass ratio of the egg white protein powder, pearl powder, keratinase, neutral protease, alkaline protease, lactic acid and total water is 30-35:10-15:0.02-0.05:0.6-1:0.6-1:20-22:1100, preferably 30:10:0.02:0.6:0.6:20:1100.

[0015] In the present invention, all proteases, including keratinase, neutral protease and alkaline protease, are sourced from Cangzhou Xiasheng Enzyme Biotechnology Co., Ltd.

[0016] Preferably, in step 1), the heating temperature is 88-95°C, preferably 90°C;

[0017] Preferably, in step 2), the cooling temperature is 45-60°C, preferably 50°C;

[0018] Preferably, in step 2), the time of one enzymatic hydrolysis is 4-6 hours, preferably 4 hours;

[0019] Preferably, in step 3), the secondary enzymatic hydrolysis time is 4-6 h, preferably 4 h;

[0020] Preferably, in step 4), the acid hydrolysis time is 1-3 h, preferably 2 h;

[0021] Preferably, in step 4), the heating temperature is 88-95°C, preferably 90°C;

[0022] Preferably, in step 4), the cooling temperature is room temperature.

[0023] Preferably, the enzymatic hydrolysis in step 2) can be carried out in two steps, that is, first, the egg white pearl powder solution pretreated in step 1) is cooled and then keratinase is added to carry out the first step of enzymatic hydrolysis, and then neutral protease is added to carry out the second step of enzymatic hydrolysis to obtain an enzymatically hydrolyzed egg white pearl powder solution;

[0024] Preferably, the time for the first step of the primary enzymatic hydrolysis and the second step of the primary enzymatic hydrolysis is 4-6 hours, preferably 4 hours, respectively.

[0025] Preferably, the method further comprises the step of adjusting the pH value before adding alkaline protease in step 3), preferably adjusting the pH value to 8.5-10.5, preferably 9.0;

[0026] Preferably, the method further comprises the step of controlling the pH value after adding alkaline protease for secondary enzymolysis in step 3), preferably controlling the pH value to 8.5-10.5, preferably 9.0.

[0027] In a specific embodiment, the method for preparing the soluble egg white protein pearl polypeptide powder of the present invention comprises the following steps:

[0028] 1) 30 g of egg white protein powder and 10 g of pearl powder were mixed with 600 ml of water, and heated to 90° C. for pretreatment to obtain a pretreated egg white protein pearl powder solution;

[0029] 2) cooling the egg white pearl powder solution pretreated in step 1) to 50° C., adding 0.02 g keratinase and 0.6 g neutral protease to perform enzymolysis for 4 h, to obtain an enzymolyzed egg white pearl powder solution;

[0030] 3) adjusting the pH value of the egg white pearl powder solution obtained by the primary enzymatic hydrolysis in step 2) to 9.0, adding 0.6 g of alkaline protease for secondary enzymatic hydrolysis for 4 h, and controlling the pH value to 9.0 with 0.2 M sodium hydroxide to obtain a secondary enzymatic hydrolyzed egg white pearl powder solution;

[0031] 4) The egg white pearl powder solution obtained by secondary enzymatic hydrolysis in step 3) is heated to 90° C., and 20 ml of lactic acid is slowly added for acid hydrolysis for 2 h. After the acid hydrolysis is completed, the solution is cooled to room temperature. During the cooling process, 500 ml of pure water is added. The cooled solution is filtered to obtain a clarified solution, and the solution is freeze-dried to obtain the product.

[0032] In another specific embodiment, the method for preparing the soluble egg white protein pearl polypeptide powder of the present invention comprises the following steps:

[0033] 1) 30 g of egg white protein powder and 10 g of pearl powder were mixed with 600 ml of water, and heated to 90° C. for pretreatment to obtain a pretreated egg white protein pearl powder solution;

[0034] 2) cooling the egg white pearl powder solution pretreated in step 1) to 50° C., adding 0.02 g of keratinase to perform a first step of enzymolysis for 4 h, and then adding 0.6 g of neutral protease to perform a second step of enzymolysis for 4 h, to obtain an egg white pearl powder solution after enzymolysis;

[0035] 3) adjusting the pH value of the egg white pearl powder solution obtained by the primary enzymatic hydrolysis in step 2) to 9.0, adding 0.6 g of alkaline protease for secondary enzymatic hydrolysis for 4 h, and controlling the pH value to 9.0 with 0.2 M sodium hydroxide to obtain a secondary enzymatic hydrolyzed egg white pearl powder solution;

[0036] 4) The egg white pearl powder solution obtained by secondary enzymatic hydrolysis in step 3) is heated to 90° C., and 20 ml of lactic acid is slowly added for acid hydrolysis for 2 h. After the acid hydrolysis is completed, the solution is cooled to room temperature. During the cooling process, 500 ml of pure water is added. The cooled solution is filtered to obtain a clarified solution, and the solution is freeze-dried to obtain the product.

[0037] Compared with the prior art, the method of the present invention hydrolyzes egg white protein and pearl powder together, and in addition to conventional neutral proteases, keratinase and alkaline proteases are additionally added to hydrolyze most of the proteases into small-molecule polypeptides and amino acids; then acid hydrolysis is performed to convert calcium carbonate in the pearl powder into active calcium that is easily absorbed by the human body, and during the acid hydrolysis process, large-molecule proteins are further acid-hydrolyzed into small-molecule polypeptides and amino acids, and the proteases are inactivated at the same time.

[0038] The method greatly increases the content of small molecule polypeptides and amino acids in soluble pearl powder, is easy to operate, does not require enzymatic hydrolysis of egg white protein in advance, reduces processing steps, shortens processing time, and saves costs.

[0039] The method of the present invention can greatly increase the protein content of the enzymatic hydrolyzate by adding egg white protein simultaneously, and after enzymatic hydrolysis by keratinase, neutral protease and alkaline protease, the macromolecular protein is enzymatically hydrolyzed into small molecular polypeptides and amino acids, which are more conducive to human body absorption. The simultaneous enzymatic hydrolysis of pearl powder and egg white protein not only shortens the enzymatic hydrolysis time, but also inactivates the enzyme simultaneously during the acid hydrolysis process, killing two birds with one stone.

[0040] The amino acids of the present invention account for 25%-30%, small molecule polypeptides account for 30%-50%, and macromolecular proteins with a molecular weight of more than 3000D account for less than 3%. The above percentages are purity percentages. DETAILED DESCRIPTION

[0041] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies realized based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0042] Embodiment 1:

[0043] 1) Mix 30g egg white protein powder and 10g pearl powder with 600ml water and heat to 90℃ for pretreatment;

[0044] 2) After cooling to 50°C, 0.02 g keratinase and 0.6 g neutral protease were added to carry out enzymatic hydrolysis for 4 h;

[0045] 3) After the first enzymatic hydrolysis was completed, the pH was adjusted to 9.0, and 0.6 g of alkaline protease was added for a second enzymatic hydrolysis for 4 h, and the pH was controlled to 9.0 with 0.2 M sodium hydroxide;

[0046] 4) After the secondary enzymatic hydrolysis is completed, the mixture is heated to 90°C and 20 ml of lactic acid is slowly added for acid hydrolysis for 2 h; after the acid hydrolysis is completed, the mixture is cooled to room temperature and 500 ml of pure water is added during the cooling process; the cooled liquid is filtered to obtain a clarified liquid with a protein content of 10.5 g / L; the liquid is freeze-dried to obtain a soluble polypeptide pearl powder, and the molecular weight distribution of the polypeptide is detected. The results are shown in Table 1:

[0047] Table 1

[0048]

[0049] Embodiment 2:

[0050] 1) Mix 30g egg white protein powder and 10g pearl powder with 600ml water and heat to 90℃ for pretreatment;

[0051] 2) After cooling to 50°C, 0.05 g keratinase and 0.6 g neutral protease were added to carry out enzymatic hydrolysis for 4 h;

[0052] 3) After the first enzymatic hydrolysis was completed, the pH was adjusted to 9.0, and 0.8 g of alkaline protease was added for a second enzymatic hydrolysis for 4 h, and the pH was controlled to 9.0 with 0.2 M sodium hydroxide;

[0053] 4) After the secondary enzymatic hydrolysis is completed, the mixture is heated to 90°C and 20 ml of lactic acid is slowly added for acid hydrolysis for 2 h; after the acid hydrolysis is completed, the mixture is cooled to room temperature and 500 ml of pure water is added during the cooling process; the cooled liquid is filtered to obtain a clarified liquid with a protein content of 10.2 g / L; the liquid is freeze-dried to obtain a soluble polypeptide pearl powder, and the polypeptide molecular weight distribution is detected; the results are shown in Table 2:

[0054] Table 2

[0055]

[0056] Embodiment 3:

[0057] 1) Mix 30g egg white protein powder and 15g pearl powder with 600ml water and heat to 90℃ for pretreatment;

[0058] 2) After cooling to 50°C, 0.03 g keratinase and 0.6 g neutral protease were added to carry out enzymatic hydrolysis for 4 h;

[0059] 3) After the first enzymatic hydrolysis was completed, the pH was adjusted to 9.0, and 0.6 g of alkaline protease was added for a second enzymatic hydrolysis for 4 h, and the pH was controlled to 9.0 with 0.2 M sodium hydroxide;

[0060] 4) After the secondary enzymatic hydrolysis is completed, the mixture is heated to 90°C and 20 ml of lactic acid is slowly added for acid hydrolysis for 2 h; after the acid hydrolysis is completed, the mixture is cooled to room temperature and 500 ml of pure water is added during the cooling process; the cooled liquid is filtered to obtain a clarified liquid with a protein content of 10.7 g / L; the liquid is freeze-dried to obtain a soluble polypeptide pearl powder, and the polypeptide molecular weight distribution is detected; the results are shown in Table 3:

[0061] Table 3

[0062]

[0063] Embodiment 4:

[0064] 1) Mix 35g egg white protein powder and 10g pearl powder with 600ml water and heat to 90°C for pretreatment;

[0065] 2) After cooling to 50°C, 0.02 g keratinase and 0.6 g neutral protease were added to carry out enzymatic hydrolysis for 4 h;

[0066] 3) After the first enzymatic hydrolysis was completed, the pH was adjusted to 9.0, and 0.7 g of alkaline protease was added for a second enzymatic hydrolysis for 4 h, and the pH was controlled to 9.0 with 0.2 M sodium hydroxide;

[0067] 4) After the secondary enzymatic hydrolysis is completed, the mixture is heated to 90°C and 20 ml of lactic acid is slowly added for acid hydrolysis for 2 h; after the acid hydrolysis is completed, the mixture is cooled to room temperature and 500 ml of pure water is added during the cooling process; the cooled liquid is filtered to obtain a clarified liquid with a protein content of 10.3 g / L; the liquid is freeze-dried to obtain a soluble polypeptide pearl powder, and the polypeptide molecular weight distribution is detected; the results are shown in Table 4:

[0068] Table 4

[0069]

[0070] Embodiment 5:

[0071] 1) Mix 30g egg white protein powder and 10g pearl powder with 600ml water and heat to 90℃ for pretreatment;

[0072] 2) After cooling to 50°C, add 0.02 g of keratinase and perform the first step of enzymatic hydrolysis for 4 h;

[0073] 3) After the first step of enzymatic hydrolysis was completed, 0.6 g of neutral protease was added to carry out the second step of enzymatic hydrolysis for 4 h;

[0074] 4) After the first enzymatic hydrolysis was completed, the pH was adjusted to 9.0, and 0.6 g of alkaline protease was added for a second enzymatic hydrolysis for 4 h, and the pH was controlled to 9.0 with 0.2 M sodium hydroxide;

[0075] 5) After the secondary enzymatic hydrolysis is completed, the mixture is heated to 90°C and 20 ml of lactic acid is slowly added for acid hydrolysis for 2 h; after the acid hydrolysis is completed, the mixture is cooled to room temperature and 500 ml of pure water is added during the cooling process; the cooled liquid is filtered to obtain a clarified liquid with a protein content of 9.98 g / L; the liquid is freeze-dried to obtain a soluble polypeptide pearl powder, and the polypeptide molecular weight distribution is detected; the results are shown in Table 5:

[0076] Table 5

[0077]

[0078]

[0079] Embodiment 6:

[0080] 1) Mix 30g egg white protein powder and 10g pearl powder with 600ml water and heat to 90℃ for pretreatment;

[0081] 2) After cooling to 50°C, 0.02 g keratinase and 0.6 g neutral protease were added to perform enzymatic hydrolysis for 6 h;

[0082] 3) After the first enzymatic hydrolysis was completed, the pH was adjusted to 9.0, and 0.6 g of alkaline protease was added for a second enzymatic hydrolysis for 6 h, and the pH was controlled to 9.0 with 0.2 M sodium hydroxide;

[0083] 4) After the secondary enzymatic hydrolysis is completed, the mixture is heated to 90°C and 20 ml of lactic acid is slowly added for acid hydrolysis for 2 h; after the acid hydrolysis is completed, the mixture is cooled to room temperature, and 500 ml of pure water is added during the cooling process; the cooled liquid is filtered to obtain a clarified liquid with a protein content of 10.0 g / L; the liquid is freeze-dried to obtain a soluble polypeptide pearl powder, and the polypeptide molecular weight distribution is detected; the results are shown in Table 6:

[0084] Table 6

[0085]

[0086]

[0087] Comparative Example 1:

[0088] 1) Mix 10g pearl powder with 100ml water and heat to 90℃;

[0089] 2) Slowly add 20 ml of lactic acid for acid hydrolysis for 2 h;

[0090] 3) After the acid hydrolysis is completed, cool to room temperature and add 450 ml of pure water during the cooling process;

[0091] 4) After cooling to 50°C, 0.6 g of neutral protease was added for enzymatic hydrolysis for 4 h;

[0092] 5) After the enzymatic hydrolysis is completed, heat to 90°C to inactivate the protease;

[0093] 6) The cooled liquid was filtered to obtain a clarified liquid with a protein content of 0.92 g / L;

[0094] 7) The feed solution was freeze-dried to obtain soluble polypeptide pearl powder, and the polypeptide molecular weight distribution was detected; the results are shown in Table 7:

[0095] Table 7

[0096]

[0097] It can be seen that without adding albumin, the protein content of the enzymatic hydrolysate prepared by this method is very low, and 1.1% of the macromolecular protein is not hydrolyzed.

[0098] Comparative Example 2:

[0099] 1) Mix 30g of egg white protein powder with 600ml of water and heat to 90°C for pretreatment;

[0100] 2) After cooling to 50°C, 0.6 g of neutral protease was added to perform enzymatic hydrolysis for 8 h;

[0101] 3) After the first enzymatic hydrolysis was completed, 0.6 g of neutral protease was added for a second enzymatic hydrolysis for 8 h;

[0102] 4) After the secondary enzymatic hydrolysis is completed, the mixture is heated to 90°C to inactivate the enzyme;

[0103] 5) Cooling the mixture to room temperature, filtering the cooled liquid to obtain clarified liquid A;

[0104] 6) 10g pearl powder was mixed with 100ml water and heated to 90℃ for pretreatment;

[0105] 7) After cooling to 50°C, add 0.6 g of neutral protease and perform enzymolysis for 8 h;

[0106] 8) After the first enzymatic hydrolysis was completed, 0.2 g of neutral protease was added for a second enzymatic hydrolysis for 8 h;

[0107] 9) After the secondary enzymatic hydrolysis is completed, heat to 90°C and slowly add 20 ml of lactic acid for acid hydrolysis for 2 hours;

[0108] 10) After the acid hydrolysis is completed, cool to room temperature and add 450 ml of pure water during the cooling process;

[0109] 11) Filter the cooled liquid to obtain clarified liquid B;

[0110] 12) Mixing liquid A and liquid B in equal proportions, with a protein content of 11.3 g / L;

[0111] 13) The mixed liquid was freeze-dried to obtain soluble polypeptide pearl powder, and the molecular weight distribution of the polypeptide was detected; the results are shown in Table 8:

[0112] Table 8

[0113]

[0114] It can be seen that in this method, egg protein and pearl powder are hydrolyzed by neutral protease respectively, and there are still many large molecular proteins in the mixed liquid that have not been hydrolyzed by the enzyme.

[0115] Comparative Example 3:

[0116] 1) Mix 30g egg white protein powder and 10g pearl powder with 600ml water and heat to 90℃ for pretreatment;

[0117] 2) After cooling to 50°C, 0.6 g of neutral protease was added to perform enzymatic hydrolysis for 4 h;

[0118] 3) After the first enzymatic hydrolysis was completed, 0.6 g of neutral protease was added for a second enzymatic hydrolysis for 4 h;

[0119] 4) After the secondary enzymatic hydrolysis is completed, heat to 90°C and slowly add 20 ml of lactic acid for acid hydrolysis for 2 h;

[0120] 5) After the acid hydrolysis is completed, cool to room temperature and add 500 ml of pure water during the cooling process;

[0121] 6) The cooled liquid was filtered to obtain a clarified liquid with a protein content of 11.7 g / L;

[0122] 7) The feed liquid was freeze-dried to obtain soluble polypeptide pearl powder, and the molecular weight distribution of the polypeptide was detected; the results are shown in Table 9:

[0123] Table 9

[0124]

[0125] It can be seen that when keratinase was not added and alkaline protease was replaced by neutral protease, a large amount of macromolecular proteins were not hydrolyzed.

[0126] Comparative Example 4:

[0127] 1) Mix 30g egg white protein powder and 10g pearl powder with 600ml water and heat to 90℃ for pretreatment;

[0128] 2) After cooling to 50°C, 0.6 g of neutral protease was added to perform enzymatic hydrolysis for 4 h;

[0129] 3) After the first enzymatic hydrolysis was completed, the pH was adjusted to 9.0, and 0.6 g of alkaline protease was added for a second enzymatic hydrolysis for 4 h, and the pH was controlled to 9.0 with 0.2 M sodium hydroxide;

[0130] 4) After the secondary enzymatic hydrolysis is completed, heat to 90°C and slowly add 20 ml of lactic acid for acid hydrolysis for 2 h;

[0131] 5) After the acid hydrolysis is completed, cool to room temperature and add 500 ml of pure water during the cooling process;

[0132] 6) The cooled liquid was filtered to obtain a clarified liquid with a protein content of 10.5 g / L;

[0133] 7) The feed liquid was freeze-dried to obtain soluble polypeptide pearl powder, and the polypeptide molecular weight distribution was detected; the results are shown in Table 10:

[0134] Table 10

[0135]

[0136] It can be seen that without the addition of keratinase, more large molecular proteins were not enzymatically hydrolyzed.

[0137] Comparative Example 5:

[0138] 1) Mix 30g egg white protein powder and 10g pearl powder with 600ml water and heat to 90℃ for pretreatment;

[0139] 2) After cooling to 50°C, 0.02 g keratinase and 0.6 g neutral protease were added to carry out enzymatic hydrolysis for 4 h;

[0140] 3) After the first enzymatic hydrolysis was completed, 0.6 g of neutral protease was added for a second enzymatic hydrolysis for 4 h;

[0141] 4) After the secondary enzymatic hydrolysis is completed, heat to 90°C and slowly add 20 ml of lactic acid for acid hydrolysis for 2 h;

[0142] 5) After the acid hydrolysis is completed, cool to room temperature and add 500 ml of pure water during the cooling process;

[0143] 6) The cooled liquid was filtered to obtain a clarified liquid with a protein content of 10.8 g / L;

[0144] 7) The feed solution was freeze-dried to obtain soluble polypeptide pearl powder, and the polypeptide molecular weight distribution was detected; the results are shown in Table 11:

[0145] Table 11

[0146]

[0147] It can be seen that when alkaline protease was replaced by neutral protease, more large molecular proteins were not hydrolyzed.

[0148] Comparative Example 6:

[0149] 1) Mix 30g egg white protein powder and 10g pearl powder with 600ml water and heat to 90℃ for pretreatment;

[0150] 2) After cooling to 50°C, 0.02 g keratinase and 0.6 g neutral protease were added to carry out enzymatic hydrolysis for 4 h;

[0151] 3) After the first enzymatic hydrolysis was completed, 0.6 g of papain was added for a second enzymatic hydrolysis for 4 h;

[0152] 4) After the secondary enzymatic hydrolysis is completed, heat to 90°C and slowly add 20 ml of lactic acid for acid hydrolysis for 2 h;

[0153] 5) After the acid hydrolysis is completed, cool to room temperature and add 500 ml of pure water during the cooling process;

[0154] 6) The cooled liquid was filtered to obtain a clarified liquid with a protein content of 10.8 g / L;

[0155] 7) The feed solution was freeze-dried to obtain soluble polypeptide pearl powder, and the polypeptide molecular weight distribution was detected; the results are shown in Table 12:

[0156] Table 12

[0157]

[0158] It can be seen that when alkaline protease was replaced by papain, more macromolecular proteins were not hydrolyzed.

[0159] Comparative Example 7:

[0160] 1) Mix 30g egg white protein powder and 10g pearl powder with 600ml water and heat to 90℃ for pretreatment;

[0161] 2) After cooling to 50°C, 0.02 g keratinase and 0.6 g neutral protease were added to carry out enzymatic hydrolysis for 4 h;

[0162] 3) After the first enzymatic hydrolysis was completed, the pH was adjusted to 9.0, and 0.55 g of alkaline protease was added for a second enzymatic hydrolysis for 4 h, and the pH was controlled to 9.0 with 0.2 M sodium hydroxide;

[0163] 4) After the secondary enzymatic hydrolysis is completed, heat to 90°C and slowly add 20 ml of lactic acid for acid hydrolysis for 2 h;

[0164] 5) After the acid hydrolysis is completed, cool to room temperature and add 500 ml of pure water during the cooling process;

[0165] 6) The cooled liquid was filtered to obtain a clarified liquid with a protein content of 10.5 g / L;

[0166] 7) The feed liquid was freeze-dried to obtain soluble polypeptide pearl powder, and the polypeptide molecular weight distribution was detected; the results are shown in Table 13:

[0167] Table 13

[0168]

[0169] It can be seen that by reducing the dosage of alkaline protease, more macromolecular proteins were not hydrolyzed by the enzyme.

Claims

1. A method for preparing soluble egg white protein pearl polypeptide powder, the method comprising the following steps: 1) mixing egg white protein powder and pearl powder with water, and heating for pretreatment to obtain a pretreated egg white protein pearl powder solution; 2) cooling the egg white pearl powder solution pretreated in step 1), and then adding keratinase and neutral protease to perform enzymolysis to obtain an enzymolyzed egg white pearl powder solution; 3) adding alkaline protease to the egg white pearl powder solution obtained by the primary enzymatic hydrolysis in step 2) to perform secondary enzymatic hydrolysis to obtain a secondary enzymatic hydrolyzed egg white pearl powder solution; 4) heating the egg white protein pearl powder solution obtained by secondary enzymatic hydrolysis in step 3), slowly adding lactic acid for acid hydrolysis, cooling, adding water during the cooling process, filtering, and freeze-drying the solution to obtain the product.

2. The preparation method according to claim 1, wherein The mass ratio of the egg white protein powder, pearl powder, keratinase, neutral protease, alkaline protease, lactic acid and total water is 30-35:10-15:0.02-0.05:0.6-1:0.6-1:20-22:1100, preferably 30:10:0.02:0.6:0.6:20:1100.

3. The preparation method according to claim 1 or 2, wherein In step 1), the heating temperature is 88-95°C, preferably 90°C.

4. The preparation method according to any one of claims 1 to 3, wherein In step 2), the cooling temperature is 45-60°C, preferably 50°C.

5. The preparation method according to any one of claims 1 to 4, wherein In step 2), the time of one enzymatic hydrolysis is 4-6 hours, preferably 4 hours.

6. The preparation method according to any one of claims 1 to 5, wherein In step 3), the secondary enzymatic hydrolysis time is 4-6 h, preferably 4 h.

7. The preparation method according to any one of claims 1 to 6, wherein In step 4), the acid hydrolysis time is 1-3 h, preferably 2 h.

8. The preparation method according to any one of claims 1 to 7, wherein In step 4), the heating temperature is 88-95°C, preferably 90°C; Preferably, in step 4), the cooling temperature is room temperature.

9. The preparation method according to any one of claims 1 to 8, wherein The enzymatic hydrolysis of step 2) is carried out in two steps, namely, firstly, the egg white pearl powder solution pretreated in step 1) is cooled and then keratinase is added to carry out the first step of enzymatic hydrolysis, and then neutral protease is added to carry out the second step of enzymatic hydrolysis to obtain an enzymatically hydrolyzed egg white pearl powder solution; Preferably, the time for the first step of the primary enzymatic hydrolysis and the second step of the primary enzymatic hydrolysis is 4-6 hours respectively, preferably 4 hours respectively.

10. The preparation method according to any one of claims 1 to 9, wherein The method further comprises the step of adjusting the pH value before adding alkaline protease in step 3), preferably adjusting the pH value to 8.5-10.5, preferably 9.0; Preferably, the method further comprises the step of controlling the pH value after adding alkaline protease for secondary enzymolysis in step 3), preferably controlling the pH value to 8.5-10.5, preferably 9.0.

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