A kind of wool keratin and its application

Abstract

The present invention provides a wool keratin and its application. By carrying out refined preparation on the prepared wool keratin, keratins with different effects and different molecular weights can be obtained. The three kinds of keratins prepared by the present invention have different molecular weights. The wool keratin amino acids can easily penetrate into the hair cortex and crosslink with the hydrophilic groups exposed in damaged hair quality to form bonds, playing the roles of moisturizing, strengthening and repairing hair, and are suitable for forked and dry hair. The medium molecular weight wool keratin is rich in proteins and polypeptide fragments, can combine with hair to form a water-insoluble polymer, and form a transparent film with a certain elasticity and strength on the hair surface, thereby improving hair elasticity, consolidating the care effect, enhancing hair luster, and playing the roles of repairing and lubricating hair filaments. The low molecular weight wool keratin contains various free amino acids and protein polypeptide fragments at the same time, acts on hair to endow hair with a moist and smooth touch, and is suitable for hair of ordinary hair quality.

Description

Technical Field

[0001] The invention belongs to the technical field of keratin separation and purification, and particularly relates to wool keratin and application thereof. Background Art

[0002] Keratin is a fibrous protein found throughout the epidermis and hair of humans and animals. It is a crucial structural protein in ectoderm cells, playing a protective role. Protein accounts for 80% to 85% of human hair, of which 80% to 90% is keratin. Hair lacking protein can easily lose its elasticity and luster. Exposure to sunlight, chemical treatments, environmental pollution, and mechanical damage can cause hair scales to warp and break, increase the amount of acidic components that decompose, and lead to a significant loss of keratin.

[0003] By comparing the types of amino acids in proteins extracted from various animals and plants (soybeans, corn, fish collagen, silk, and wool), it is found that keratin extracted from wool has the most similar amino acid composition to human hair. Therefore, using keratin extracted from wool as a nutritional and repairing ingredient for human hair is easier to act on the hair and be absorbed by the hair, achieving the purpose of repairing the hair scales and improving the warping of the hair scales.

[0004] Currently, commonly used methods for extracting wool keratin mostly use acids, alkalis, enzymes, oxidants, reducing agents, high temperature and high pressure extraction, but each method has different drawbacks. For example, high concentrations of strong acids and alkalis can significantly damage keratin, not only breaking up salt bonds but also destroying peptide bonds. This can lead to the loss of keratin's specific functional activity and pose environmental pollution risks when used in industrial production. Enzymatic degradation reactions take too long, generally reaching more than 10 hours, and wool degradation is insufficient. Using only oxidants and reducing agents for keratin extraction results in relatively low subsequent separation efficiency, low product purity, and impracticality for large-scale production. Furthermore, currently, the degradation products of wool keratin are not very effective in hair care. Summary of the Invention

[0005] The purpose of the present invention is to provide a wool keratin and an application thereof, and to obtain keratin with different effects and different molecular weights by refining the prepared wool keratin.

[0006] The present invention first provides a method for preparing keratin with different molecular weights from wool, comprising the following steps:

[0007] 1) Wool pretreatment:

[0008] After washing the wool, soak it in sodium hydroxide solution at 45-55°C, and then grind the wool soaked in the solution into wool powder.

[0009] Among them, as a specific record of an embodiment, the concentration of the sodium hydroxide alkali solution is 0.1-0.5%;

[0010] 2) Degrading wool by high-temperature and high-pressure oxidation method:

[0011] Adding the pulverized wool powder to the hydrogen peroxide solution and treating it under high-temperature and high-pressure conditions to obtain a wool keratin extract;

[0012] Among them, the concentration of the hydrogen peroxide solution is preferably 5%-10%;

[0013] As a specific record of an embodiment, the high-temperature and high-pressure conditions are to carry out the treatment at 110°C-125°C and 0.15 MPa to obtain a wool keratin extract;

[0014] 3) Separation of keratin with different molecular weights:

[0015] Filtering the wool keratin extract to remove large particles suspended in the liquid to obtain a filtrate;

[0016] The filtration, as a specific record of an embodiment, is to separate the keratin liquid through a 500-mesh bag filter, and the separated wool keratin liquid passes through a 1-μm pp cotton filter to remove large particles suspended in the liquid to obtain a filtrate;

[0017] Passing the filtrate through an ultrafiltration membrane column with a cut-off molecular weight of 50 kDa to obtain a mixed wool keratin liquid of medium molecular weight, low molecular weight, and amino acids. Passing the mixed wool keratin liquid through an ultrafiltration membrane column with a cut-off molecular weight of 10 kDa, and the liquid that does not pass through the 10-kDa ultrafiltration membrane column, after drying, is medium molecular weight wool keratin with a molecular weight of 10 kDa-50 kDa;

[0018] The liquid passing through the 10-kDa ultrafiltration membrane column is a liquid with a molecular weight below 10 kDa. Then passing this liquid through a nanofiltration membrane column with a cut-off molecular weight of 500 Da, and the liquid that does not pass through this nanofiltration membrane column, after drying, is low molecular weight wool keratin with a molecular weight of 500 Da-10 kDa;

[0019] The permeate passing through the 500-Da nanofiltration membrane column, after drying, is wool keratin amino acids with a molecular weight of 0-500 Da.

[0020] At this time, medium molecular weight wool keratin with a molecular weight of 10 kDa-50 kDa, low molecular weight wool keratin with a molecular weight of 500 Da-10 kDa, and wool keratin amino acid polypeptides with a molecular weight of 0-500 Da are respectively obtained.

[0021] The wool keratin with different molecular weights prepared by the present invention can be used to prepare hair care products;

[0022] In another aspect, the present invention provides a hair care product, which contains any one or several of the above three different molecular weight wool keratins;

[0023] As a specific hair care product, the addition amount of keratin amino acids is 1-20%, the addition amount of low molecular weight wool keratin is 1-20%, and the addition amount of medium molecular weight keratin is 1-5%.

[0024] The three kinds of keratins prepared by the present invention have different molecular weights. Wool keratin amino acids can easily penetrate into the hair cortex and crosslink with the hydrophilic groups exposed in damaged hair quality, playing the role of moisturizing, strengthening and repairing hair, and are suitable for forked and dry hair. Medium molecular weight wool keratin is rich in proteins and polypeptide fragments, which can combine with hair to form a water-insoluble polymer, forming a transparent film with a certain elasticity and strength on the hair surface, thereby improving hair elasticity, consolidating the care effect, enhancing hair luster, and playing the role of repairing and lubricating hair filaments, and is suitable for frizzy and dry hair. While low molecular weight wool keratin contains various free amino acids and protein polypeptide fragments at the same time, which acts on hair to give hair a moist and smooth touch, and is suitable for ordinary hair quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 High performance gel permeation chromatography analysis chart of wool keratin amino acids,

[0026] Figure 2 High performance gel permeation chromatography analysis chart of low molecular weight wool keratin,

[0027] Figure 3 High performance gel permeation chromatography analysis chart of medium molecular weight wool keratin,

[0028] Figure 4 Moisture absorption comparison chart of hair before and after treatment, where note: "##" has a significant difference from the blank group, and "**" has a significant difference from the control group, with statistical significance, P<0.05;

[0029] Figure 5 Moisture retention comparison chart of hair before and after treatment,

[0030] Figure 6 Scanning electron microscope images of hair cuticle repair before and after treatment, where A: ordinary hair conditioner (control group), B: hair conditioner added with 5% keratin amino acids (5% AC group), C: hair conditioner added with 5% low molecular weight keratin (5% LF group), D: hair conditioner added with 5% medium molecular weight keratin (5% MF group);

[0031] Figure 7, Fluorescent calibration penetration maps of hair before and after treatment, where A is keratin amino acids, B is low molecular weight keratin, and C is medium molecular weight keratin. Detailed implementation mode

[0032] The applicant's research found that the keratin extracted from wool contains a large number of various protein fragments, polypeptide long chains, and free amino acids with different molecular weights. By extracting and separating keratin products with different molecular weights from wool and selecting different molecular weights for application according to actual needs, the advantages of keratin with different molecular weights can be better maximized.

[0033] Aiming at the deficiencies in the extraction of wool keratin and the separation and purification technology of keratin with different molecular weights in the prior art, starting from the physical structure and chemical properties of keratin in wool, this invention analyzes and studies the degradation mechanism of keratin in wool. The established method can effectively overcome the disadvantages such as too high reaction pressure in the high-pressure hydrolysis method and too long reaction time in the peroxide method.

[0034] After the wool is degraded by the high-temperature and high-pressure oxidation method in this invention, the wool contains a large number of keratin fragments with different molecular weights. Ultrafiltration membranes and nanofiltration membranes can intercept keratin fragments with different molecular weights to complete the extraction and separation of three kinds of keratin with different molecular weights (keratin amino acids, low molecular weight keratin, and medium molecular weight keratin) in wool; and determine the usage effects of keratin with different molecular weights.

[0035] The method for preparing keratin in wool provided by this invention first includes the following steps:

[0036] 1) Wool pretreatment: Wash the wool to remove impurities such as doped wool, soil, and sheep manure. Soak the wool in sodium hydroxide solution at 45 - 55 °C for 2 hours, then wash the wool. Use a centrifuge to remove grease, sweat, etc. on the surface of the wool. Then the wool is pulverized into wool powder about 0.5 - 1.0 cm by a pulverizer.

[0037] As a specific record of the embodiment, the concentration of the sodium hydroxide solution is 0.2%, but sodium hydroxide solutions with other concentrations or other existing alkaline solutions for wool pretreatment can also be used.

[0038] 2) Degrade the wool by the high-temperature and high-pressure oxidation method: Put the pulverized wool powder into a high-temperature pressure cooker, add hydrogen peroxide solution, and react at 110 °C - 125 °C and 0.15 MPa for 30 min - 60 min. Obtain the wool keratin extract and the unreacted residue.

[0039] The concentration of the hydrogen peroxide solution is preferably 5% - 10%, and the input weight ratio of the wool powder to the hydrogen peroxide solution is 1:5 - 1:10;

[0040] 3) Separation of keratin with different molecular weights: The obtained wool keratin extraction solution and the unreacted residue were separated by a 500-mesh bag filter to obtain keratin liquid and the unreacted residue. The separated wool keratin liquid passed through a 1-μm pp cotton filter to remove large particles suspended in the liquid and obtain a filtrate.

[0041] 4) Separation of medium-molecular-weight wool keratin: The filtrate was passed through an ultrafiltration membrane column with a cut-off molecular weight of 50 kDa. At this time, the obtained liquid was a mixed wool keratin solution of medium molecular weight, low molecular weight, and amino acids. This mixed solution was then passed through an ultrafiltration membrane column with a cut-off molecular weight of 10 kDa. The liquid that did not pass through the 10-kDa ultrafiltration membrane column was dried to obtain medium-molecular-weight wool keratin with a molecular weight of 10 kDa - 50 kDa.

[0042] The liquid that passed through the 10-kDa ultrafiltration membrane column was a liquid with a molecular weight below 10 kDa. This liquid was then passed through a nanofiltration membrane column with a cut-off molecular weight of 500 Da. The liquid that did not pass through this nanofiltration membrane column was dried to obtain low-molecular-weight wool keratin with a molecular weight of 500 Da - 10 kDa.

[0043] The permeate that passed through the 500-Da nanofiltration membrane column was dried to obtain wool keratin amino acids with a molecular weight of 0 - 500 Da.

[0044] At this time, medium-molecular-weight wool keratin with a molecular weight of 10 kDa - 50 kDa, low-molecular-weight wool keratin with a molecular weight of 500 Da - 10 kDa, and wool keratin amino acid polypeptides with a molecular weight of 0 - 500 Da were respectively obtained.

[0045] The present invention will be described in detail below in conjunction with the embodiments and the accompanying drawings.

[0046] Example 1: Preparation of wool keratin with different molecular weights

[0047] 1) Wool pretreatment

[0048] The sheep wool was washed to remove dirt and debris, dried, soaked in a 0.2% sodium hydroxide solution at 50°C for 1 h, then the wool treated with the alkali solution was washed to remove the residual alkali solution, and after drying, it was pulverized into 0.5-cm wool powder by a pulverizer.

[0049] 2) Degradation of wool by high-temperature and high-pressure oxidation method:

[0050] 100 kg of the pulverized wool powder was added to 500 L of a 5% hydrogen peroxide solution, and the mixture was put into a high-temperature and high-pressure cooking pot and reacted at 110°C and 0.15 MPa for 30 min to obtain a preliminary degraded solution of wool keratin;

[0051] 3) Separation of keratin with different molecular weights:

[0052] The obtained preliminary degradation solution of wool keratin is separated from dregs and liquid through a bag filter with a mesh size of 500, and the separated liquid is passed through a pp cotton filter with a pore size of 1μm to remove large particles suspended in the liquid, obtaining a filtrate;

[0053] 4) Separation of medium, low molecular weight and amino acid wool keratin:

[0054] The liquid obtained by passing the above filtrate through an ultrafiltration membrane column with a cut-off molecular weight of 50 kDa is a mixed wool keratin solution of medium molecular weight, low molecular weight and amino acids. The mixed wool keratin solution is then passed through an ultrafiltration membrane column with a cut-off molecular weight of 10 kDa. The liquid that does not pass through the ultrafiltration membrane column with a cut-off molecular weight of 10 kDa, after drying, is medium molecular weight wool keratin with a molecular weight range of 10 kDa - 50 kDa;

[0055] The liquid passing through the ultrafiltration membrane column with a cut-off molecular weight of 10 kDa is a liquid with a molecular weight below 10 kDa. Then this liquid is passed through a nanofiltration membrane column with a cut-off molecular weight of 500 Da. The liquid that does not pass through this nanofiltration membrane column, after drying, is low molecular weight wool keratin with a molecular weight range of 500 Da - 10 kDa;

[0056] The permeate passing through the nanofiltration membrane column with a cut-off molecular weight of 500 Da, after drying, is wool keratin amino acids with a molecular weight range of 0 - 500 Da.

[0057] At this time, medium molecular weight wool keratin with a molecular weight range of 10 kDa - 50 kDa, low molecular weight wool keratin with a molecular weight range of 500 Da - 10 kDa, and wool keratin amino acids with a molecular weight range of 0 - 500 Da are respectively obtained.

[0058] 5) Weigh the dried products of the above-mentioned medium molecular weight wool keratin, low molecular weight wool keratin, and wool keratin amino acids, and calculate that the yield of medium molecular weight wool keratin is 24.56%, the yield of low molecular weight wool keratin is 32.83%, and the yield of wool keratin amino acids is 12.83%.

[0059] 6) High performance gel permeation chromatography is used to detect the molecular weights of the prepared medium molecular weight wool keratin, low molecular weight wool keratin, and wool keratin amino acids. The weight average molecular weight of wool keratin amino acids is 0.19 kDa, and the dispersion coefficient is 0.72( Figure 1 ). The weight average molecular weight of low molecular weight wool keratin is 1.96 kDa, and the dispersion coefficient is 2.19( Figure 2 ). The weight average molecular weight of medium molecular weight wool keratin is 26.7 kDa, and the dispersion coefficient is 2.32( Figure 3 ).

[0060] Example 2: Hair care efficacy test of keratin with different molecular weights

[0061] Perform hair care efficacy tests on the keratin amino acids, low molecular weight keratin, and medium molecular weight keratin prepared in Example 1 above.

[0062] The test methods are as follows: Use water (blank group), ordinary hair conditioner (control group), hair conditioner with 5% keratin amino acids added (AC group), hair conditioner with 5% low molecular weight keratin added (LF group), and hair conditioner with 5% medium molecular weight keratin added (MF group) to conduct tests on real hair for in vitro soaking, washing, weighing, scanning electron microscopy imaging, and tensile strength. Among the control group, AC group, LF group, and MF group, the other components are the same except for the addition of keratin fragments with different molecular weights.

[0063] 1. Analysis of hair hygroscopicity test

[0064] Hair treated with water and hair treated with different hair conditioners can absorb moisture from the air, but the water absorption rate of the former is significantly lower than that of the latter. With the addition of different molecular weight fragments of keratin in the hair conditioner, the water absorption rate of the hair also varies. The water absorption rate of hair treated with 5% keratin amino acids, low molecular weight keratin, and medium molecular weight keratin reached over 10% at 12 h, meeting the requirement of 10%-15% water content for healthy hair, and their water absorption rates are better than those of hair treated with ordinary hair conditioner. The water absorption rate of hair treated with a hair conditioner containing 5% low molecular weight keratin for 12 h is better than that of other molecular weight fragments, and the water absorption rate of hair treated with a hair conditioner containing 5% medium molecular weight keratin for 24 h is better than that of hair treated with hair conditioners of other molecular weight fragments. And low molecular weight keratin performs better in terms of hygroscopicity.

[0065] 2. Analysis of hair moisturizing test

[0066] The water loss rate of hair treated with water reaches 4.5% after being placed in a dry environment for 24 h. With the addition of different molecular weight fragments of keratin in the hair conditioner, the water loss rate of the hair decreases. The water loss rate of hair treated with hair conditioners containing different molecular weight fragments of keratin for 12 h or 24 h is lower than that of hair treated with ordinary hair conditioner, and the water loss rate of hair treated with a hair conditioner containing 5% medium molecular weight keratin for 12 h or 24 h is lower than that of hair treated with hair conditioners of other molecular weight fragments. Thus, it can be seen that hair conditioners added with different molecular weight fragments of keratin have good moisturizing functions for hair, and medium molecular weight keratin performs better in terms of moisturizing.

[0067] 3. Cuticle repair test

[0068] Results analysis showed that the surface of hair treated with ordinary hair conditioner was evenly covered with tile-like scales. The scale openings were large, the ends were defective, exposing the inner cortex, and the hair was rough and had poor luster. For the hair treated with 5% keratin amino acid hair conditioner (5% AC group), the scale openings were smaller and more uniform than those of the untreated hair. For the hair treated with 5% low molecular weight keratin hair conditioner (5% LF group), the scale openings were even smaller, and the scale length was shorter and more uniform. For the hair treated with 5% medium molecular weight keratin hair conditioner (5% MF group), the scales closely adhered to the hair shaft, the scale length was short, and it was plump and shiny. Comprehensive analysis showed that keratin with different molecular weights had good repair effects on hair, but as the molecular weight increased, it was more likely to form a protective film on the hair surface and close the hair scales. Medium molecular weight keratin had a better effect on repairing hair scales.

[0069] 4. Hair permeability test (using fluorescence FITC calibration)

[0070] The results showed that the fluorescence intensity signal of keratin amino acids inside the hair was significantly greater than that of low molecular weight keratin and medium molecular weight keratin, and the signal of medium molecular weight keratin was weak. It can be seen that keratin amino acids had strong permeability, and their polypeptides and amino acids could penetrate through the hair cortex to supplement the nutrients lost by the hair and achieve the repair effect. However, the penetration effect of medium molecular weight keratin in the hair strands was not ideal, and it did not have much effect on supplementing the nutrients of the hair strands through penetration.

[0071] 5. Hair strength test

[0072] Table 1: Comparison table of tensile strength after hair treatment

[0073]

[0074] The results showed that hair strands were prone to brittle fracture under external stimuli. The strength of hair treated with keratin of different molecular weights was improved, and medium molecular weight keratin had a more obvious effect on improving hair strength.

[0075] In summary, keratin extracted from wool achieved the purpose of repairing hair in two aspects. On the one hand, it supplemented the required amino acids, polypeptides and other nutrients inside the hair strands, and on the other hand, it formed a protective film on the hair surface to repair the hair scales. Keratin amino acids had strong permeability to hair, and their polypeptides and amino acids could achieve the purpose of repairing hair scales by supplementing the required amino acids, polypeptides and other nutrients inside the hair strands. Medium molecular weight keratin was more likely to form a film on the hair surface, making the hair not easily brittle and preventing further damage to the hair. Low molecular weight keratin could not only play the role of supplementing the nutrients of the hair strands, but also form a protective film on the surface, but the effect was not as good as using keratin amino acids and medium molecular weight keratin alone.

Claims

1. A preparation method for preparing keratin with different molecular weights from wool, characterized in that, The different molecular weight keratin refers to medium molecular weight wool keratin with a molecular weight of 10 kDa - 50 kDa, low molecular weight wool keratin with a molecular weight of 500 Da - 10 kDa, and wool keratin amino acid polypeptides with a molecular weight of 0 - 500 Da. The preparation method includes the following steps: 1) Wool pretreatment: After washing the wool, soak it in a sodium hydroxide solution at 45 - 55 °C, and then crush the soaked wool into wool powder; The concentration of the sodium hydroxide solution is 0.1% - 0.5%; 2) Degrading wool by high temperature and high pressure oxidation method: Add the crushed wool powder into a hydrogen peroxide solution and treat it under high temperature and high pressure conditions to obtain a wool keratin extract; The concentration of the hydrogen peroxide solution is 5% - 10%, and the high temperature and high pressure conditions are treatment at 110 °C - 125 °C and 0.15 MPa to obtain the wool keratin extract; 3) Separation of different molecular weight keratin: Filter the wool keratin extract to remove large particles suspended in the liquid to obtain a filtrate, and pass the filtrate through an ultrafiltration membrane column with a cut-off molecular weight of 50 kDa to obtain a mixed wool keratin solution, Pass the mixed wool keratin solution through an ultrafiltration membrane column with a cut-off molecular weight of 10 kDa again, and dry the retentate to obtain medium molecular weight wool keratin with a molecular weight of 10 kDa - 50 kDa; Pass the mixed wool keratin solution through an ultrafiltration membrane column with a cut-off molecular weight of 10 kDa to obtain a permeate with a molecular weight below 10 kDa. Then pass the permeate through a nanofiltration membrane column with a cut-off molecular weight of 500 Da, and dry the retentate to obtain low molecular weight wool keratin with a molecular weight of 500 Da - 10 kDa; while dry the permeate to obtain wool keratin amino acids with a molecular weight of 0 - 500 Da; The filtration is to separate the keratin liquid through a 500-mesh bag filter, and the separated wool keratin liquid passes through a 1-µm pp cotton filter to obtain a filtrate.

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