阅读说明：本技术 一种利用腌制原皮生产牛皮明胶的方法 (Method for producing oxhide gelatin by using pickled raw skin ) 是由 杜赟 崔�根 潘美针 王璇 邱学如 于 2021-01-14 设计创作，主要内容包括：本发明属于明胶提取技术领域,具体涉及一种利用腌制原皮生产牛皮明胶的方法。该方法通过以下步骤实现：将牛皮脱毛,清洗后脱脂；将脱脂后的牛皮经梯度氯化钠-三乙醇胺水溶液进行搅拌浸泡,浸泡完成后过滤清洗牛皮；将处理后的牛皮加入含有十二烷基硫酸钠的磷酸盐缓冲溶液中,加入酸性蛋白酶及磺化琥珀酸二辛酯钠盐,进行酶解,酶解结束后进行酶钝化；将酶解后的牛皮清洗至中性后,振荡溶胶,过滤得胶液,将胶液离心,收集上清液后冷冻干燥即可。本发明提供的提取方法,能够提高明胶提取率,且提取的明胶纯度高,且符合药用牛皮明胶的相关标准,粒度均一；本发明提供的方法能够缩短酶解时间,但不影响明胶得率。(The invention belongs to the technical field of gelatin extraction, and particularly relates to a method for producing oxhide gelatin by using pickled raw skins. The method is realized by the following steps: removing hair from cow leather, cleaning, and degreasing; stirring and soaking the degreased cowhide in a gradient sodium chloride-triethanolamine aqueous solution, and filtering and cleaning the cowhide after soaking; adding the treated cow leather into a phosphate buffer solution containing sodium dodecyl sulfate, adding acid protease and dioctyl sodium sulfosuccinate for enzymolysis, and performing enzyme passivation after the enzymolysis is finished; cleaning the cow leather after enzymolysis to be neutral, oscillating sol, filtering to obtain glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying. The extraction method provided by the invention can improve the extraction rate of the gelatin, and the extracted gelatin has high purity, meets the relevant standards of medicinal oxhide gelatin and has uniform granularity; the method provided by the invention can shorten the enzymolysis time without influencing the gelatin yield.)

1. A method for producing oxhide gelatin by using pickled raw skins is characterized by comprising the following steps:

(1) cleaning the surface of the raw cowhide after unhairing, cutting the raw cowhide into blocks, and degreasing to obtain degreased cowhide for later use;

(2) stirring and soaking the degreased cowhide in a gradient sodium chloride-triethanolamine aqueous solution for 2-2.5h, filtering after soaking, and washing the cowhide with deionized water;

(3) adding the treated cow leather into phosphate buffer solution containing 0.1-0.3% of lauryl sodium sulfate, adding acid protease and dioctyl sodium sulfosuccinate for enzymolysis, and performing enzyme passivation after the enzymolysis is finished;

(4) cleaning the cow leather after enzymolysis to be neutral, adding distilled water at 60 ℃, oscillating sol for 4h, then filtering to obtain a glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying.

2. The method according to claim 1, wherein in the step (1), the solvent used for degreasing is lauric acid-isopropanol-water in a ratio of 0.8-1: 5: 20; the degreasing time is 3-5 h.

3. The method according to claim 1 or 2, wherein in step (2), the specific gradient of the gradient sodium chloride-triethanolamine aqueous solution is as follows: the first gradient is 2.5-3% sodium chloride aqueous solution; the second gradient is 5.0-5.5% sodium chloride aqueous solution; the third gradient is 8-8.5% sodium chloride aqueous solution; the mass ratio of the sodium chloride to the triethanolamine is 4: 1.

4. The method according to any one of claims 1 to 3, wherein the feed-to-liquid ratio of the cow leather to the sodium chloride-triethanolamine aqueous solution is 1 g/20-25 mL.

5. The method according to claim 1, wherein in the step (3), the ratio of cow leather to phosphate buffer solution containing sodium dodecyl sulfate is 1g:30 mL; the pH value of the phosphate buffer solution is 6.5-6.8.

6. The method according to claim 1 or 6, wherein the amount of the acidic protease added is 1800-2500/g of the weight of the cowhide; the mass concentration of the dioctyl sodium sulfosuccinate in the buffer solution is 0.8%.

7. The method of claim 1, 5 or 6, wherein the enzymatic hydrolysis is carried out at 35-38 ℃ for 28-30 h.

8. The method according to claim 7, wherein in the step (4), the mass ratio of the cow leather to the distilled water is 1: 30.

Technical Field

The invention belongs to the technical field of gelatin extraction, and particularly relates to a method for producing oxhide gelatin by using pickled raw skins.

Background

Gelatin, which is a protein partially hydrolyzed from collagen in connective or epidermal tissues of animals, is a protein having a special amino acid composition and few sulfur-containing amino acids, but has high contents of glycine, alanine, proline and hydroxyproline, the more 67% of the total amino acids, and is nearly colorless or pale yellow in appearance, a transparent, odorless solid, and excellent physical and chemical properties such as formation of reversible gel, cohesiveness, surface activity, etc., and is widely used as a jelly, an emulsifier, a stabilizer, an adhesive, etc. in the food industry.

The raw materials for producing the gelatin mainly comprise skins, bones, muscle tendons and the like of various livestock. At present, the extraction method of gelatin mainly comprises the following steps: (1) the method is suitable for preparing the gelatin by using the aggregate and the pigskin, the raw materials are hard after the acid treatment, and the treatment time is long; (2) the raw material containing collagen is pretreated by lime suspension, sodium hydroxide solution and the like to extract the gelatin, and the method has high utilization rate; (3) the mixed solution of sodium sulfate and sodium hydroxide replaces lime milk to dip the raw material to produce gelatin, which is a common method for producing gelatin by adopting cow leather, but the method is easy to pollute the environment, and when the concentration of the sodium hydroxide is not properly adjusted, collagen fibers are easy to melt, so that the raw material is rotten; (4) the gelatin is extracted by dissolving collagen and performing thermal denaturation through enzyme treatment, the production period of the method is short, the environmental pollution is small, but the local dissolution of the collagen is easily caused in the enzymolysis extraction process, the enzymolysis liquid is sticky, the yield is low, and the like.

Chinese patent CN201811441992.6 provides a method for producing oxhide gelatin by an alkaline process, which improves the extraction efficiency by performing four times of extraction after sodium sulfide treatment, alkali liquor treatment and the like, but the method has long period and complex process. Therefore, the development of a method which can efficiently extract gelatin from cow leather and has high gelatin purity is a problem to be solved urgently.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for producing oxhide gelatin by using pickled raw skins, and the oxhide gelatin extracted by the method has high yield and good quality.

The technical scheme adopted by the invention for realizing the purpose is as follows:

the invention provides a method for producing oxhide gelatin by using pickled raw skins, which comprises the following steps:

(1) cleaning the surface of the unhaired cowhide raw skin, cutting the unhaired cowhide raw skin into blocks, and degreasing to obtain degreased cowhide for later use;

(2) stirring and soaking the degreased cowhide in a gradient sodium chloride-triethanolamine aqueous solution for 2 hours, filtering after soaking, and washing the cowhide with deionized water;

(3) adding the treated cow leather into phosphate buffer solution containing 0.1-0.3% of lauryl sodium sulfate, adding acid protease and dioctyl sodium sulfosuccinate for enzymolysis, and performing enzyme passivation after the enzymolysis is finished;

(4) cleaning the cow leather after enzymolysis to be neutral, adding distilled water at 60 ℃, oscillating sol for 4h, then filtering to obtain a glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying.

Further, in the step (1), the solvent used for degreasing is lauric acid-isopropanol-water, and the ratio of lauric acid-isopropanol-water is 0.8-1: 5: 20; the degreasing time is 3-5 h.

The concrete gradient of the gradient sodium chloride-triethanolamine aqueous solution used by the invention is as follows: the first gradient was 3% aqueous sodium chloride; the second gradient was 5.5% aqueous sodium chloride; the third gradient is 8% sodium chloride aqueous solution; the mass ratio of the sodium chloride to the triethanolamine is 4: 1.

The feed-liquid ratio of the cow leather to the sodium chloride-triethanolamine aqueous solution is 1g:20-25 mL.

Further, in the step (3), the feed-liquid ratio of the cow leather to the phosphate buffer solution containing 0.3% of sodium dodecyl sulfate is 1g:30 mL; the pH value of the phosphate buffer solution is 6.5-6.8.

Further, the adding amount of the acid protease accounts for 1800-; the mass concentration of the dioctyl sodium sulfosuccinate in the buffer solution is 0.8%.

Further, the enzymolysis is carried out for 28-30h at 35-38 ℃.

Further, in the step (4), the mass ratio of the cow leather to the distilled water is 1: 30.

According to the extraction method provided by the invention, the cowhide is soaked in the sodium chloride solution with a certain gradient concentration, so that the cowhide is subjected to gradient swelling, under the dual actions of triethanolamine and sodium chloride, foreign proteins can not be removed completely, and meanwhile, degreasing is further carried out, so that the extraction rate of subsequent gelatin is improved, and the quality is improved.

The invention has the beneficial effects that:

(1) the extraction method provided by the invention can improve the extraction rate of the gelatin, and the extracted gelatin has high purity, meets the relevant standards of medicinal oxhide gelatin and has uniform granularity;

(2) the method provided by the invention can shorten the enzymolysis time without influencing the gelatin yield.

Detailed Description

The technical solution of the present invention is further explained and illustrated by the following specific examples.

Example 1

(1) Cleaning the surface of the unhaired cowhide raw skin, cutting into blocks, and mixing with lauric acid-isopropanol-water according to a ratio of 1:5: degreasing the degreasing agent consisting of 20 for 3 hours to obtain degreased cowhide for later use;

(2) adding 20mL of gradient sodium chloride-triethanolamine aqueous solution into each 1g of degreased cow leather, stirring and soaking for 2h, wherein the first gradient is 3% sodium chloride aqueous solution; the second gradient was 5.5% aqueous sodium chloride; the third gradient is 8% sodium chloride aqueous solution; the mass ratio of the sodium chloride to the triethanolamine is 4:1, filtering is carried out after soaking is finished, and the cowhide is washed by deionized water;

(3) adding 30mL of phosphate buffer solution containing 0.3% of lauryl sodium sulfate into each g of treated cow leather, adding 2000U/g of acid protease and dioctyl sodium sulfosuccinate (the addition amount is 0.8% of mass concentration in the buffer solution), performing enzymolysis for 28h at 35-38 ℃, and performing enzyme passivation after the enzymolysis is finished;

(4) cleaning the cow leather after enzymolysis to be neutral, adding 30 times of distilled water, oscillating sol for 4h, filtering to obtain a glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying.

Example 2

(1) Cleaning the surface of the unhaired cowhide raw skin, cutting into blocks, and mixing with lauric acid-isopropanol-water according to a ratio of 0.8: 5: degreasing the degreasing agent consisting of 20 for 3 hours to obtain degreased cowhide for later use;

(2) adding 25mL of gradient sodium chloride-triethanolamine aqueous solution into each 1g of degreased cow leather, stirring and soaking, wherein each gradient is soaked for 2 hours, and the first gradient is 2.5% of sodium chloride aqueous solution; the second gradient was 5.5% aqueous sodium chloride; the third gradient was 8.5% aqueous sodium chloride; the mass ratio of the sodium chloride to the triethanolamine is 4:1, filtering is carried out after soaking is finished, and the cowhide is washed by deionized water;

(3) adding 30mL of phosphate buffer solution containing 0.2% of lauryl sodium sulfate into each g of treated cow leather, adding 2500U/g of acid protease and dioctyl sodium sulfosuccinate (the addition amount is 0.8% of the mass concentration in the buffer solution), performing enzymolysis for 30h at 35-38 ℃, and performing enzyme passivation after the enzymolysis is finished;

(4) cleaning the cow leather after enzymolysis to be neutral, adding 30 times of distilled water, oscillating sol for 4h, filtering to obtain a glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying.

Example 3

(1) Cleaning the surface of the unhaired cowhide raw skin, cutting into blocks, and mixing with lauric acid-isopropanol-water according to a ratio of 0.9: 5: degreasing the degreasing agent consisting of 20 for 3 hours to obtain degreased cowhide for later use;

(2) adding 20mL of gradient sodium chloride-triethanolamine aqueous solution into each 1g of degreased cow leather, stirring and soaking for 2h, wherein the first gradient is 3% sodium chloride aqueous solution; the second gradient was 5.0% aqueous sodium chloride; the third gradient was 8.5% aqueous sodium chloride; the mass ratio of the sodium chloride to the triethanolamine is 4:1, filtering is carried out after soaking is finished, and the cowhide is washed by deionized water;

(3) adding 30mL of phosphate buffer solution containing 0.25% of lauryl sodium sulfate into each g of treated cow leather, adding 1800U/g of acid protease and dioctyl sodium sulfosuccinate (the addition amount is 0.8% of the mass concentration in the buffer solution), performing enzymolysis for 30h at 35-38 ℃, and performing enzyme passivation after the enzymolysis is finished;

(4) cleaning the cow leather after enzymolysis to be neutral, adding 30 times of distilled water, oscillating sol for 4h, filtering to obtain a glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying.

Comparative example 1

(1) Cleaning the surface of the raw cowhide after unhairing, cutting the raw cowhide into blocks, and degreasing for 3 hours by using a degreasing agent consisting of lauric acid-isopropanol-water according to a ratio of 1:5:20 to obtain degreased cowhide for later use;

(2) adding 20mL of sodium chloride-triethanolamine aqueous solution into every 1g of degreased cow leather, stirring and soaking for 6 hours, wherein the concentration of the sodium chloride aqueous solution is 3%, the mass ratio of the sodium chloride to the triethanolamine is 4:1, filtering after soaking, and washing the cow leather with deionized water; (3) adding 30mL of phosphate buffer solution containing 0.3% of lauryl sodium sulfate into each g of treated cow leather, adding 2000U/g of acid protease and dioctyl sodium sulfosuccinate (the addition amount is 0.8% of mass concentration in the buffer solution), performing enzymolysis for 28h at 35-38 ℃, and performing enzyme passivation after the enzymolysis is finished;

(4) cleaning the cow leather after enzymolysis to be neutral, adding 30 times of 60 ℃ distilled water, oscillating the sol for 4 hours, then filtering to obtain a glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying.

Comparative example 2

(1) Cleaning the surface of the raw cowhide after unhairing, cutting the raw cowhide into blocks, and degreasing for 3 hours by using a degreasing agent consisting of lauric acid-isopropanol-water according to a ratio of 1:5:20 to obtain degreased cowhide for later use;

(2) adding 20mL of sodium chloride-triethanolamine aqueous solution into every 1g of degreased cow hide, stirring, soaking for 6h, wherein the concentration of the sodium chloride aqueous solution is 5.5%, and the mass ratio of sodium chloride to triethanolamine is 4:1, filtering after soaking, and washing the cow hide with deionized water; (3) adding 30mL of phosphate buffer solution containing 0.3% of lauryl sodium sulfate into each g of treated cow leather, adding 2000U/g of acid protease and dioctyl sodium sulfosuccinate (the addition amount is 0.8% of mass concentration in the buffer solution), performing enzymolysis for 28h at 35-38 ℃, and performing enzyme passivation after the enzymolysis is finished;

(4) cleaning the cow leather after enzymolysis to be neutral, adding 30 times of 60 ℃ distilled water, oscillating the sol for 4 hours, then filtering to obtain a glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying.

Comparative example 3

(1) Cleaning the surface of the raw cowhide after unhairing, cutting the raw cowhide into blocks, and degreasing for 3 hours by using a degreasing agent consisting of lauric acid-isopropanol-water according to a ratio of 1:5:20 to obtain degreased cowhide for later use;

(2) adding 20mL of sodium chloride-triethanolamine aqueous solution into every 1g of degreased cow leather, stirring and soaking for 6 hours, wherein the concentration of the sodium chloride aqueous solution is 8%, the mass ratio of the sodium chloride to the triethanolamine is 4:1, filtering after soaking, and washing the cow leather with deionized water; (3) adding 30mL of phosphate buffer solution containing 0.3% of lauryl sodium sulfate into each g of treated cow leather, adding 2500U/g of acid protease and dioctyl sodium sulfosuccinate (the addition amount is 0.8% of the mass concentration in the buffer solution), performing enzymolysis for 30h at 35-38 ℃, and performing enzyme passivation after the enzymolysis is finished;

(4) cleaning the cow leather after enzymolysis to be neutral, adding 30 times of 60 ℃ distilled water, oscillating the sol for 4 hours, then filtering to obtain a glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying.

Comparative example 4

(1) Cleaning the surface of the raw cowhide after unhairing, cutting the raw cowhide into blocks, and degreasing for 3 hours by using a degreasing agent consisting of lauric acid-isopropanol-water according to a ratio of 1:5:20 to obtain degreased cowhide for later use;

(2) adding 20mL of gradient sodium chloride-triethanolamine aqueous solution into each 1g of degreased cow leather, stirring and soaking for 2h, wherein the first gradient is 3% sodium chloride aqueous solution; the second gradient was 5.5% aqueous sodium chloride; the third gradient is 8% sodium chloride aqueous solution; the mass ratio of the sodium chloride to the triethanolamine is 4:1, filtering is carried out after soaking is finished, and the cowhide is washed by deionized water; (3) adding 30mL of phosphate buffer solution containing 0.3% of lauryl sodium sulfate into each g of treated cow leather, adding 2000U/g of acid protease, performing enzymolysis at 35-38 ℃ for 30h, and performing enzyme passivation after the enzymolysis is finished;

(4) cleaning the cow leather after enzymolysis to be neutral, adding 30 times of 60 ℃ distilled water, oscillating the sol for 4 hours, then filtering to obtain a glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying.

Comparative example 5

(1) Cleaning the surface of cowhide, cutting into blocks, degreasing for 3h by adopting an isopropanol-water degreasing agent according to a ratio of 6:20 to obtain degreased cowhide for later use;

(2) adding 20mL of 10% sodium chloride aqueous solution into each 1g of degreased cow leather, stirring, soaking for 6h, filtering after soaking, and washing the cow leather with deionized water;

(3) adding 30mL of phosphate buffer solution containing 0.3% of lauryl sodium sulfate into each g of treated cow leather, adding 2000U/g of acid protease, performing enzymolysis at 35-38 ℃ for 30h, and performing enzyme passivation after the enzymolysis is finished;

(4) cleaning the cow leather after enzymolysis to be neutral, adding 30 times of 60 ℃ distilled water, oscillating the sol for 4 hours, then filtering to obtain a glue solution, centrifuging the glue solution, collecting supernatant, and freeze-drying.

Effects of the embodiment

Firstly, after gelatin in pickled cowhide is extracted in the examples and the comparative examples, the extraction rate of the gelatin is counted, meanwhile, the extracted gelatin is subjected to gel strength detection, a texture analyzer is used for detecting the gel strength, a gelatin water solution with the concentration of 6.67% (w/v) is prepared, then the gelatin water solution is placed at 10 ℃ for 16 hours to form a sample with the diameter of 4.0cm and the height of 5.0cm, then a probe with the diameter of 12.7mm is adopted, the testing distance is 4.0mm, the testing speed is 0.5mm/s, five groups of parallel tests are set, and the maximum pressure (g) which can be born by the prepared sample is the gel strength;

the gelatin extraction rate was calculated as follows:

the extraction rate of cow hide gelatin (the mass of the finished product of gelatin after freeze drying/dry weight of fresh cow hide) is 100%;

the specific results are shown in table 1.

TABLE 1

(II) the viscosity of the oxhide gelatin prepared in the examples and the comparative examples is detected: preparing 38% gelatin water solution, keeping the temperature at 40 ℃ by adopting a viscometer, pulling out a wood plug at a bottom hole of the suspension viscometer, recording the time when the suspension viscometer bears 200mL of the gelatin solution in a bottle, and dividing the used time by 51 seconds to obtain the viscosity value, wherein the specific result is shown in Table 2.

TABLE 2

Thirdly, the bovine hide gelatin prepared in example 1 and comparative examples 1 to 5 was subjected to the detection of the contents of fat and collagen according to GB6783-2001, and the specific results are shown in Table 3.

TABLE 3