阅读说明：本技术 一种牦牛毛的角蛋白提取方法 (Method for extracting keratin from yak hair ) 是由 李凤红 王哲 于 2021-08-09 设计创作，主要内容包括：本发明涉及一种牦牛毛的角蛋白提取方法,步骤：先将牦牛毛进行清洗去除表面污物,再放入离心机进行脱水,洗净甩干后的牦牛毛放入预处理液中,调节pH为7-9,于70-100℃温度条件下预处理30-50分钟；将牦牛毛放入离心机进行脱水,洗净甩干后放入柔顺剂中,于25-40℃温度条件下柔顺30-60分钟；将牦牛毛洗净,放入水中浸泡20-30分钟,再清洗甩干后放入烘箱,在40-70℃温度下烘干；将烘干的牦牛毛剪碎成5 mm以内的碎渣,放入溶解液,在温度为155-165℃条件下溶解40-60分钟；溶解完成后加入少量去离子水,对溶液进行真空抽滤,用透析袋对滤液进行48小时透析；将透析后的角蛋白溶液进行真空冷冻干燥24-48小时,得到角蛋白粉末。本发明的牦牛毛溶解率提高至96%以上,提取率可达45%以上。(The invention relates to a method for extracting keratin from yak hair, which comprises the following steps: cleaning yak hair to remove dirt on the surface, then putting the yak hair into a centrifuge for dehydration, putting the cleaned and dried yak hair into pretreatment liquid, adjusting the pH to 7-9, and pretreating for 30-50 minutes at the temperature of 70-100 ℃; placing yak hair into a centrifuge for dewatering, cleaning, spin-drying, placing into a softener, and softening at 25-40 deg.C for 30-60 min; cleaning yak hair, soaking in water for 20-30 min, cleaning, drying, oven drying at 40-70 deg.C; cutting the dried yak hair into crushed slag within 5mm, putting the crushed slag into a dissolving solution, and dissolving for 40-60 minutes at the temperature of 155-165 ℃; after the dissolution is finished, adding a small amount of deionized water, carrying out vacuum filtration on the solution, and dialyzing the filtrate for 48 hours by using a dialysis bag; and (3) carrying out vacuum freeze drying on the dialyzed keratin solution for 24-48 hours to obtain keratin powder. The dissolution rate of the yak hair is improved to more than 96%, and the extraction rate can reach more than 45%.)

1. A method for extracting keratin from yak hair is characterized by comprising the following steps:

the method comprises the following steps:

pretreatment: cleaning yak hair to remove dirt on the surface, then putting the yak hair into a centrifuge for dehydration, putting the cleaned and dried yak hair into pretreatment liquid, adjusting the pH to 7-9, and pretreating for 30-50 minutes at the temperature of 70-100 ℃;

and (3) softening treatment: placing yak hair into a centrifuge for dewatering, cleaning, spin-drying, placing into a softener, and softening at 25-40 deg.C for 30-60 min;

cleaning and drying: cleaning yak hair, soaking in water for 20-30 min, cleaning, drying, oven drying at 40-70 deg.C;

dissolving yak hair: cutting the dried yak hair into crushed slag within 5mm, putting the crushed slag into a dissolving solution, and dissolving for 40-60 minutes at the temperature of 155-165 ℃;

and (3) dialysis: after the dissolution is finished, adding a small amount of deionized water, carrying out vacuum filtration on the solution, and dialyzing the filtrate for 48 hours by using a dialysis bag;

and (3) freeze drying: and (3) carrying out vacuum freeze drying on the dialyzed keratin solution for 24-48 hours to obtain keratin powder.

2. The method for extracting keratin from yak hair according to claim 1, wherein: the pretreatment liquid comprises the following components in parts by weight: 5-10 parts of sodium bisulfite and 90-95 parts of water; the mass ratio of the yak hair to the pretreatment liquid is 1:20-1: 30.

3. The method for extracting keratin from yak hair according to claim 1, wherein: the softener comprises the following components in parts by mass: 6-8 parts of polydimethylsiloxane, 2-3 parts of stearic acid polyoxyethylene ether, 50-55 parts of water, and the mass ratio of yak hair to the solution is 1:20-1: 30.

4. The method for extracting keratin from yak hair according to claim 3, wherein: the preparation method of the softener comprises the following steps: mixing polydimethylsiloxane, stearic acid polyoxyethylene ether and water in proportion, putting the mixture into an oven, standing the mixture at the temperature of between 50 and 70 ℃ for 10 to 20 minutes to fully dissolve the stearic acid polyoxyethylene ether, uniformly stirring the mixture for 2 minutes, cooling the mixture to room temperature, and uniformly stirring the mixture to obtain the emulsified softener.

5. The method for extracting keratin from yak hair according to claim 1, wherein: the dissolving solution comprises the following components in parts by weight: 1-3 parts of sodium bisulfite and 27-33 parts of urea, and the mixture is molten under the temperature of 155-165 ℃; the mass ratio of the yak hair to the dissolving solution is 1: 9-12.

Technical Field

The invention relates to the technical field of yak hair resource utilization, in particular to a method for extracting keratin from yak hair.

Background

The yaks are special rare species in China, the number of the yaks in China is about 95% of the total number of the yaks in the world, most of the yaks are distributed in the Qinghai-Tibet plateau area with the altitude of more than 3000 m, and the yaks are cold-resistant because the surfaces of the yaks are covered with thick yak hair. The average annual yak hair production of each yak is about 2kg, wherein the fluff which can be used for spinning only accounts for about 30 percent, and the remainder is coarse yak hair. The diameter of the coarse hair of the yaks is distributed between 70 and 150 mu m, which is 2 to 5 times of that of the hair of common animals (such as wool and the like), and the length of the coarse hair of the yaks is 2 to 3 times of that of common textile raw materials such as wool and the like. The thickness of the scale layer is about 200-600 nm, and the structure is in a imbricate shape. Keratin is the main protein constituting yak hair, has two space structures of alpha-helix and beta-fold, and contains more than twenty amino acids. The highest content of the proteins is cystine, so that the disulfide bond content is higher, the keratin has higher stability and is difficult to dissolve in water, and the dissolution rate of the yak hair keratin by a general protein extraction method is lower. This also makes the mechanical strength of the yak coarse hair high. The characteristics of rigidity, hardness, small crimpness, poor cohesion and the like make the application of the fiber in the aspect of spinning difficult, most of coarse wool is treated as waste, which is a great waste of resources, but keratin can be extracted from the fiber, the fiber is used for the fields of producing feed, pesticide, cosmetics and the like, and the waste of resources is reduced. At present, keratin is mainly extracted from wool, the price of yak coarse hair is lower than that of wool, and the keratin is extracted from the yak coarse hair, so that the keratin extraction cost is reduced. However, the mechanical strength of crude yak hair is high, and the existing method has low dissolution rate and extraction rate of keratin extracted from crude yak hair.

Disclosure of Invention

The purpose of the invention is as follows: the invention provides a method for extracting keratin from yak hair, and aims to solve the problems of low dissolving rate and low extraction rate of keratin in yak hair in the prior art.

The technical scheme is as follows:

a method for extracting keratin from yak hair comprises the following steps:

pretreatment: cleaning yak hair to remove dirt on the surface, then putting the yak hair into a centrifuge for dehydration, putting the cleaned and dried yak hair into pretreatment liquid, adjusting the pH to 7-9, and pretreating for 30-50 minutes at the temperature of 70-100 ℃;

and (3) softening treatment: placing yak hair into a centrifuge for dewatering, cleaning, spin-drying, placing into a softener, and softening at 25-40 deg.C for 30-60 min;

cleaning and drying: cleaning yak hair, soaking in water for 20-30 min, cleaning, drying, oven drying at 40-70 deg.C;

dissolving yak hair: cutting the dried yak hair into crushed slag within 5mm, putting the crushed slag into a dissolving solution, and dissolving for 40-60 minutes at the temperature of 155-165 ℃;

and (3) dialysis: after the dissolution is finished, adding a small amount of deionized water, carrying out vacuum filtration on the solution, and dialyzing the filtrate for 48 hours by using a dialysis bag;

and (3) freeze drying: and (3) carrying out vacuum freeze drying on the dialyzed keratin solution for 24-48 hours to obtain keratin powder.

The pretreatment liquid comprises the following components in parts by weight: 5-10 parts of sodium bisulfite and 90-95 parts of water; the mass ratio of the yak hair to the pretreatment liquid is 1:20-1: 30.

The softener comprises the following components in parts by mass: 6-8 parts of polydimethylsiloxane, 2-3 parts of stearic acid polyoxyethylene ether, 50-55 parts of water, and the mass ratio of yak hair to the solution is 1:20-1: 30.

The viscosity of the polydimethylsiloxane is preferably 100CS, and the type of polyoxyethylene stearate is preferably SG-6.

The preparation method of the softener comprises the following steps: mixing polydimethylsiloxane, stearic acid polyoxyethylene ether and water in proportion, putting the mixture into an oven, standing the mixture at the temperature of between 50 and 70 ℃ for 10 to 20 minutes to fully dissolve the stearic acid polyoxyethylene ether, uniformly stirring the mixture for 2 minutes, cooling the mixture to room temperature, and uniformly stirring the mixture to obtain the emulsified softener.

The dissolving solution comprises the following components in parts by weight: 1-3 parts of sodium bisulfite and 27-33 parts of urea, and the mixture is molten under the temperature of 155-165 ℃; the mass ratio of the yak hair to the dissolving solution is 1: 9-12.

Has the advantages that: the method comprises the steps of carrying out pretreatment and softening treatment, adding sodium bisulfite into a dissolving solution to prevent reduction of hydrogen bonds and disulfide bonds, and under the same condition, compared with the yak hair raw hair which is not subjected to pretreatment and softening treatment, the dissolution rate is improved to more than 96% from 90.67%, and the extraction rate can reach more than 45%.

Drawings

FIG. 1 shows the elongation at break distribution of yak hair;

FIG. 2 is the fracture strength distribution of yak hair;

FIG. 3 is a graph of elongation at break-breaking strength of yak hair;

FIG. 4 is a comparison graph of the surface of filter paper after suction filtration of raw hair and treated yak hair;

fig. 5 is an infrared spectrogram of yak hair keratin.

Detailed Description

The invention is described in more detail below with reference to the accompanying drawings.

The low dissolution rate of yak hair is mainly due to excessive disulfide bonds and hydrogen bonds among molecular chains of yak hair. The method pretreats yak hair to break partial disulfide bonds and hydrogen bonds, reduces the crystallinity of the yak hair, and increases the solubility of keratin. Softening yak hair, reducing surface tension of liquid on yak hair, and increasing keratin dissolution rate. Sodium bisulfite is added into the solution to separate out a small amount of sulfur dioxide with strong reducibility under the condition of high temperature, so as to prevent partial broken hydrogen bonds from being oxidized again in the dissolving process, and simultaneously, vacuum freeze drying is used, so that the broken hydrogen bonds are prevented from being oxidized again under the common drying condition.

Example 1

1.8g of sodium bisulfite and 28.2g of deionized water were weighed to prepare a pretreatment solution, and the pH was adjusted to 8. Weighing 1g of yak hair, setting the oil bath temperature to be 90 ℃, immersing the yak hair into the pretreatment liquid, and carrying out oil bath at the constant temperature of 90 ℃ for 40 minutes. After the pretreatment is finished, cleaning yak hair with clear water, putting the yak hair into a centrifuge, setting the rotating speed to be 1000R/min, keeping for 5 minutes, and separating most of water. Then 3g of polydimethylsiloxane (100CS), 26g of water and 1g of stearic acid polyoxyethylene ether are weighed, sealed and placed in an environment at 60 ℃ for 10 minutes to dissolve the stearic acid polyoxyethylene ether. Then, the mixture is taken out and uniformly stirred, cooled to room temperature and then stirred to form viscous emulsion. And (3) putting the dehydrated yak hair into a softener, and softening for 50 minutes at the temperature of 30 ℃. And finally, cleaning the yak hair, soaking the yak hair in water for 25 minutes, cleaning residues on the surface of the yak hair, then putting the yak hair in an oven, setting the temperature at 60 ℃, and standing for 10 minutes to dry the yak hair. Weighing 0.1g of sodium bisulfite and 2.7g of urea, placing for 15 minutes at 160 ℃ to enable the mixture to be molten, shearing dried yak hair into crushed slag within 5mm, weighing 0.3g of yak hair, placing into a dissolving solution, and dissolving at 155 ℃ for 60 minutes. After dissolution was complete, 5ml of deionized water was added, the solution was vacuum filtered, and 0.0120g of insoluble material was filtered off, calculated as dissolution rate 96.0%. The filtrate was dialyzed with a dialysis bag for 48 hours. Finally, the dialyzed keratin solution was vacuum freeze-dried at-45 ℃ for 24 hours to obtain 0.1300g keratin powder, the extraction rate was calculated to be 45.14%.

Example 2

Sodium hydrogen sulfite 2.7g and deionized water 27.3g were weighed to prepare a pretreatment solution, and the pH was adjusted to 9. Weighing 1.5g of yak hair, setting the oil bath temperature at 100 ℃, immersing the yak hair into the pretreatment liquid, and carrying out constant-temperature oil bath at 100 ℃ for 30 minutes. After the pretreatment is finished, cleaning yak hair with clear water, putting the yak hair into a centrifuge, setting the rotation speed to be 1500R/min, keeping for 5 minutes, and separating most of water. Then 4g of polydimethylsiloxane (100CS), 25g of water and 1.5g of stearic acid polyoxyethylene ether are weighed, sealed and placed in an environment at 70 ℃ for 10 minutes to dissolve the stearic acid polyoxyethylene ether. Then, the mixture is taken out and uniformly stirred, cooled to room temperature and then stirred to form viscous emulsion. And (3) putting the dehydrated yak hair into a softener, and softening for 30 minutes at 40 ℃. And finally, cleaning the yak hair, soaking the yak hair in water for 30 minutes, cleaning residues on the surface of the yak hair, then putting the yak hair in an oven, setting the temperature at 45 ℃, and standing for 15 minutes to dry the yak hair. Weighing 0.3g of sodium bisulfite and 3.0g of urea, placing for 15 minutes at 160 ℃ to enable the mixture to be molten, shearing the dried yak hair into crushed slag within 5mm, weighing 0.3g of yak hair, placing into a dissolving solution, and dissolving for 50 minutes at 160 ℃. After dissolution was complete, 5ml of deionized water was added, the solution was vacuum filtered, and 0.0115g of insoluble material was filtered off, calculated as dissolution rate 96.2%. The filtrate was dialyzed with a dialysis bag for 48 hours. Finally, the dialyzed keratin solution was vacuum freeze-dried at-45 ℃ for 30 hours to obtain 0.1360g of keratin powder, the extraction rate was calculated to be 47.14%.

Example 3

3g of sodium bisulfite and 27g of deionized water are weighed to prepare a pretreatment solution, and the pH is adjusted to 7. Weighing 1.2g of yak hair, setting the oil bath temperature to be 70 ℃, immersing the yak hair into the pretreatment liquid, and carrying out oil bath at the constant temperature of 70 ℃ for 50 minutes. After the pretreatment is finished, cleaning yak hair with clear water, putting the yak hair into a centrifuge, setting the rotation speed at 1200R/min, keeping for 5 minutes, and separating most of water. Then 3g of polydimethylsiloxane (100CS), 25g of water and 1g of stearic acid polyoxyethylene ether are weighed, sealed and placed in an environment at 50 ℃ for 20 minutes to dissolve the stearic acid polyoxyethylene ether. Then, the mixture is taken out and uniformly stirred, cooled to room temperature and then stirred to form viscous emulsion. And (3) putting the dehydrated yak hair into a softener, and softening for 60 minutes at the temperature of 25 ℃. And finally, cleaning the yak hair, soaking the yak hair in water for 20 minutes, cleaning residues on the surface of the yak hair, then putting the yak hair in an oven, setting the temperature at 40 ℃, and standing for 20 minutes to dry the yak hair. Weighing 0.2g of sodium bisulfite and 2.8g of urea, placing the mixture for 15 minutes at 165 ℃ to enable the mixture to be molten, shearing the dried yak hair into crushed slag within 5mm, weighing 0.3g of yak hair, placing the yak hair into a dissolving solution, and dissolving for 40 minutes at 165 ℃. After dissolution was complete, 5ml of deionized water was added, the solution was vacuum filtered and 0.0109g of insoluble material were filtered off, the calculated dissolution rate was 96.37%. The filtrate was dialyzed with a dialysis bag for 48 hours. Finally, the dialyzed keratin solution was vacuum freeze-dried at-45 ℃ for 40 hours to obtain 0.1385g of keratin powder, the extraction rate was calculated to be 47.91%.

Example 4

Weighing 2g of sodium bisulfite and 28g of deionized water to prepare a pretreatment solution, and adjusting the pH to 7.5. Weighing 1g of yak hair, setting the oil bath temperature to be 80 ℃, immersing the yak hair into the pretreatment liquid, and carrying out oil bath at the constant temperature of 80 ℃ for 40 minutes. After the pretreatment is finished, cleaning yak hair with clear water, putting the yak hair into a centrifuge, setting the rotation speed to be 1500R/min, keeping for 5 minutes, and separating most of water. Then 4g of polydimethylsiloxane (100CS), 25g of deionized water and 1g of stearic acid polyoxyethylene ether are weighed, sealed and placed in an environment at 60 ℃ for 15 minutes to dissolve the stearic acid polyoxyethylene ether. Then, the mixture is taken out and uniformly stirred, cooled to room temperature and then stirred to form viscous emulsion. And (3) putting the dehydrated yak hair into a softener, and softening for 45 minutes at the temperature of 35 ℃. And finally, cleaning the yak hair, soaking the yak hair in water for 30 minutes, cleaning residues on the surface of the yak hair, then putting the yak hair in an oven, setting the temperature at 50 ℃, and standing for 15 minutes to dry the yak hair. Weighing 0.15g of sodium bisulfite and 2.85g of urea, placing for 15 minutes at 160 ℃ to enable the mixture to be molten, shearing dried yak hair into crushed slag within 5mm, weighing 0.3g of yak hair, placing into a dissolving solution, and dissolving for 45 minutes at 160 ℃. After dissolution was complete, 5ml of deionized water was added, the solution was vacuum filtered and 0.00765g of insoluble material were filtered off, the calculated dissolution rate was 97.45%. The filtrate was dialyzed with a dialysis bag for 48 hours. Finally, the dialyzed keratin solution was vacuum freeze-dried at-45 ℃ for 36 hours to obtain 0.1328g of keratin powder, the extraction rate was calculated to be 45.42%.

The soft and smooth yak hair obtained in example 1 and the untreated yak hair were selected to be 30 pieces each, and the elongation at break and the breaking strength of the yak hair were measured using a YG-020 type electron intensity machine (tencel textile instruments ltd., york city), and the distribution of the elongation at break of the fiber was as shown in fig. 1, and the distribution of the breaking strength was as shown in fig. 2.

From the yak hair obtained after softening in example 1 and the untreated yak hair, 1 yak hair each having similar elongation at break and fineness was selected, and a fracture elongation-fracture strength curve graph was prepared, as shown in fig. 3.

The attached figures 1 and 2 show that compared with the yak hair raw hair, the modified yak hair has more quantity distributed in the high breaking elongation range and less quantity distributed in the high breaking strength range; as shown in the attached figure 3, the yield point of the modified yak hair is moved forward, and the yield strength is reduced. This is because the degree of crystallinity is reduced, the intermolecular stress is reduced, the flexibility is improved, and the resistance to molecular slip is reduced, so that the strength is reduced, the elongation at break is increased, and the yield strength is reduced. Indicating that part of the hydrogen bonds are destroyed by sodium bisulfite under high temperature conditions.

In order to observe the dissolving effect more visually, the yak hair after dissolving is subjected to vacuum filtration by using 625-mesh filter paper, and the attached figure 4 is a comparison graph of the surface of the filter paper after the filtration of the raw hair and the treated yak hair, so that less insoluble substances are filtered out by the treated yak hair, and the higher dissolving rate is shown.

The infrared spectrum test of the extracted protein powder is carried out, and the attached figure 5 shows that the protein powder has obvious characteristics of an amide I band (1633.22), an amide II band (1515.31) and an amide III band (1234.46), and is a typical protein spectrum.