CN114891446A - Method for preparing leather gelatin by compounding alkaline method/acid method and enzymatic method - Google Patents
Method for preparing leather gelatin by compounding alkaline method/acid method and enzymatic method Download PDFInfo
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- CN114891446A CN114891446A CN202210495079.4A CN202210495079A CN114891446A CN 114891446 A CN114891446 A CN 114891446A CN 202210495079 A CN202210495079 A CN 202210495079A CN 114891446 A CN114891446 A CN 114891446A
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- 239000010985 leather Substances 0.000 title claims abstract description 127
- 238000000034 method Methods 0.000 title claims abstract description 113
- 108010010803 Gelatin Proteins 0.000 title claims abstract description 73
- 229920000159 gelatin Polymers 0.000 title claims abstract description 73
- 239000008273 gelatin Substances 0.000 title claims abstract description 73
- 235000019322 gelatine Nutrition 0.000 title claims abstract description 73
- 235000011852 gelatine desserts Nutrition 0.000 title claims abstract description 73
- 239000002253 acid Substances 0.000 title claims abstract description 32
- 238000006911 enzymatic reaction Methods 0.000 title claims abstract description 20
- 238000013329 compounding Methods 0.000 title description 5
- 102000004190 Enzymes Human genes 0.000 claims abstract description 34
- 108090000790 Enzymes Proteins 0.000 claims abstract description 34
- 239000000463 material Substances 0.000 claims abstract description 14
- 230000009849 deactivation Effects 0.000 claims abstract description 13
- 238000005520 cutting process Methods 0.000 claims abstract description 10
- 238000002161 passivation Methods 0.000 claims abstract description 10
- 238000009835 boiling Methods 0.000 claims abstract description 7
- 238000001035 drying Methods 0.000 claims abstract description 7
- 239000003292 glue Substances 0.000 claims abstract description 6
- 230000000415 inactivating effect Effects 0.000 claims abstract description 3
- 238000000746 purification Methods 0.000 claims abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 39
- 239000000243 solution Substances 0.000 claims description 18
- 238000010438 heat treatment Methods 0.000 claims description 15
- 102000004882 Lipase Human genes 0.000 claims description 14
- 108090001060 Lipase Proteins 0.000 claims description 14
- 239000004367 Lipase Substances 0.000 claims description 14
- 235000019421 lipase Nutrition 0.000 claims description 14
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 12
- 238000005406 washing Methods 0.000 claims description 9
- 108090000145 Bacillolysin Proteins 0.000 claims description 8
- 108091005658 Basic proteases Proteins 0.000 claims description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 8
- 108091005507 Neutral proteases Proteins 0.000 claims description 8
- 102000035092 Neutral proteases Human genes 0.000 claims description 8
- 108091005804 Peptidases Proteins 0.000 claims description 6
- 239000004365 Protease Substances 0.000 claims description 6
- 102100037486 Reverse transcriptase/ribonuclease H Human genes 0.000 claims description 6
- 238000001914 filtration Methods 0.000 claims description 5
- 206010033675 panniculitis Diseases 0.000 claims description 5
- 210000004304 subcutaneous tissue Anatomy 0.000 claims description 5
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 4
- 239000007864 aqueous solution Substances 0.000 claims description 2
- 230000008859 change Effects 0.000 claims description 2
- 238000005086 pumping Methods 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 23
- 238000004519 manufacturing process Methods 0.000 abstract description 12
- 102000008186 Collagen Human genes 0.000 abstract description 11
- 108010035532 Collagen Proteins 0.000 abstract description 11
- 229920001436 collagen Polymers 0.000 abstract description 11
- 238000002360 preparation method Methods 0.000 abstract description 6
- 238000007710 freezing Methods 0.000 abstract description 5
- 230000008014 freezing Effects 0.000 abstract description 5
- 239000002344 surface layer Substances 0.000 abstract description 2
- 239000003513 alkali Substances 0.000 description 9
- 208000005156 Dehydration Diseases 0.000 description 7
- 230000018044 dehydration Effects 0.000 description 7
- 238000006297 dehydration reaction Methods 0.000 description 7
- 238000010521 absorption reaction Methods 0.000 description 6
- 239000010410 layer Substances 0.000 description 5
- 239000002994 raw material Substances 0.000 description 4
- 210000003491 skin Anatomy 0.000 description 4
- 238000002791 soaking Methods 0.000 description 4
- 210000000988 bone and bone Anatomy 0.000 description 2
- 230000000593 degrading effect Effects 0.000 description 2
- 210000004207 dermis Anatomy 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000007062 hydrolysis Effects 0.000 description 2
- 238000006460 hydrolysis reaction Methods 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 108010076876 Keratins Proteins 0.000 description 1
- 102000011782 Keratins Human genes 0.000 description 1
- 241001465754 Metazoa Species 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000004925 denaturation Methods 0.000 description 1
- 230000036425 denaturation Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 210000002615 epidermis Anatomy 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 238000001935 peptisation Methods 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09H—PREPARATION OF GLUE OR GELATINE
- C09H1/00—Pretreatment of collagen-containing raw materials for the manufacture of glue
- C09H1/04—Pretreatment of collagen-containing raw materials for the manufacture of glue of hides, hoofs, or leather scrap
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09H—PREPARATION OF GLUE OR GELATINE
- C09H3/00—Isolation of glue or gelatine from raw materials, e.g. by extracting, by heating
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/74—Recovery of fats, fatty oils, fatty acids or other fatty substances, e.g. lanolin or waxes
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Treatment And Processing Of Natural Fur Or Leather (AREA)
- Preparation Of Compounds By Using Micro-Organisms (AREA)
Abstract
The invention relates to a method for preparing leather gelatin by combining an alkaline method/an acid method and an enzymatic method, which comprises the following steps: step one, cutting a leather material; step two, leather pretreatment; step three, circularly squeezing and carrying out enzymolysis; step four, inactivating enzyme and passivating; step five, post-treatment: the leather after enzyme deactivation and passivation is processed by glue boiling, purification, concentration and drying to obtain the finished product of the gelatin. The method remarkably improves the efficiency of decomposing collagen into gelatin, greatly shortens the production period compared with the traditional alkali-method gelatin preparation, and can finish the whole process within 3-5 days. Meanwhile, the efficiency of decomposing collagen into gelatin is improved, and the sol phenomenon of the thin skin and the surface layer of the skin material is reduced, so that the gelatin yield is improved by more than 8 percent compared with the traditional alkaline method; the quality of the gelatin is also obviously improved, the freezing force of the gelatin prepared by the method can be improved by more than 10 percent due to the characteristics of the gelatin, and the transparency of the gelatin is improved by more than 6 percent.
Description
Technical Field
The invention relates to a preparation process of leather gelatin, in particular to a method for preparing leather gelatin by compounding an alkaline method/an acid method and an enzymatic method.
Background
Gelatin is a product obtained by moderate hydrolysis and thermal denaturation of collagen, the raw materials for producing the gelatin mainly comprise skins and bones of animals, leather-making industry waste materials and the like, and common gelatin in the market is prepared by taking cow leather, cow bone or pig skin as raw materials. The current production methods of gelatin mainly comprise an alkaline method, an acid method, an enzymatic method and the like. The alkaline method and the acid method are traditional production methods, wherein the quality of the alkaline gelatin is better than that of the acid method, but the production period of the alkaline method is longer, generally 15 days. Because the raw materials of the raw hide are different in thickness and difficult to sort, the excessive hydrolysis of the thin raw hide can be caused by pure alkali or acid treatment to generate a sol phenomenon, so that the product yield is reduced (7-8 tons of raw hide are needed for one ton of gelatin product), the dissolved collagen and the fallen subcutaneous tissues (such as grease) enter sewage and are difficult to treat, and the discharged waste liquid has great pollution to the environment.
The gelatin prepared by the enzyme method has low production cost and high product safety, and can gradually replace gelatin produced by an acid method and an alkali method in the fields of medicine, food and the like. Compared with the traditional process for preparing the gelatin by the alkaline method, the production period for preparing the gelatin by degrading the enzyme-catalyzed collagen is greatly shortened, so that foreign gelatin workers pay attention to the research on the enzyme. The research of enzyme method gelatin preparation starts in 1962, people have recognized that gelatin can be prepared by degrading collagen by enzyme, but the enzymolysis degree is difficult to determine quickly, the enzymolysis is easy to cause excessive enzymolysis, the freezing force of a gelatin finished product is reduced seriously, the process control is difficult, and the like, and the defects influence the quality of gelatin, so that the gelatin produced by the enzyme method is difficult to industrialize.
The invention aims to improve the efficiency of decomposing collagen into gelatin by combining the prior alkali/acid method and enzyme method gelatin preparation process, and provides a method for preparing leather gelatin by compounding the alkali/acid method and the enzyme method, which has the advantages of short production period, high gelatin quality and yield and small environmental pollution.
Disclosure of Invention
The invention aims to solve the technical problems in the prior art. The invention provides a method for preparing leather gelatin by combining an alkali/acid method and an enzyme method, which adopts a gelatin preparation process combining an alkali/acid peptization process and an enzyme method, increases the surface area by cutting strips and exposes a corium layer to improve the treatment efficiency and uniformity of alkali/acid and enzyme, and further adopts circulating squeezing dehydration and water absorption to promote the enzymolysis consistency, thereby improving the efficiency of collagen decomposition into gelatin, reducing the production period and improving the quality and yield of gelatin.
The technical scheme adopted by the invention for solving the technical problems is as follows: a method for preparing leather gelatin by combining an alkaline method/an acid method and an enzymatic method comprises the following steps:
step one, cutting a leather material: cutting the cleaned whole leather into strips along one direction, wherein the width of each strip is close to the thickness of a thinner leather, parts are kept not to be cut at intervals of 5-20cm during strip cutting, the specific interval size is determined according to the size selectivity of the leather, as the non-cutting parts are left between the strips of the leather, the leather is longitudinally and transversely cut into a plurality of pieces after being cut, each piece is connected with the strips by the non-cutting parts, so that the leather is not chipped, and the filter screens of devices for separating materials from water and the like in the subsequent process cannot be blocked; in addition, after the leather is cut into thin strips, the leather is equivalently homogenized, and the time-consuming and labor-consuming sorting process is omitted; the surface area is greatly improved after slitting, and meanwhile, the dermis layer taking collagen as the main component is directly exposed (the original dermis layer is covered by the epidermis layer taking compact keratin as the main component and the subcutaneous tissue layer taking fat as the main component), so that the subsequent alkali/acid and enzyme treatment efficiency is effectively improved, the treatment time is reduced, the phenomenon that thinner skin materials are excessively treated to be sol is avoided, the yield is improved, and the sewage treatment pressure is reduced;
step two, leather pretreatment: adding the cut leather into a sodium hydroxide solution, adjusting the pH value of the solution to be 13-13.5, keeping the temperature at 15-25 ℃, treating for 2-5 days, washing with water, and adjusting the pH value to the proper pH value required by enzymolysis in the third step;
step three, circular squeezing enzymolysis: transferring the pretreated leather into an enzymolysis container, adding lipase and protease for enzymolysis, and controlling the enzymolysis temperature at 30-55 ℃;
during enzymolysis, the leather and water are pumped out together by a pump, the water is separated after water is filtered, the leather enters a roller press to be pressed and dehydrated, the line pressure of pressing is adjusted to be 20-80kN/m according to the state of the leather, the dehydrated leather returns to an enzymolysis container again to absorb aqueous solution containing enzyme, the circulation is adopted, the uniformity of the surface and the internal enzymolysis speed of the leather can be improved through the circular pressing and dehydration treatment in the enzymolysis process, the enzyme can enter the leather in the process of water absorption after the leather is dehydrated, and the inside and the outside of the leather can be uniformly subjected to enzymolysis; the leather is rubbed in the circulating squeezing dehydration process, fat and other impurities of the subcutaneous tissue are removed under the combined action of the leather and the enzyme, the quality of the gelatin is improved, the leather is subjected to enzymolysis until the strength of the leather is obviously reduced, the surface is smooth and clean, and the leather and water are separated after the subcutaneous tissue is taken out, and then the step four is carried out;
step four, inactivating enzyme and passivating: the leather material with the separated water is quickly heated for enzyme deactivation and passivation treatment, the enzyme deactivation temperature is not lower than 70 ℃, the enzyme deactivation and passivation can be quickly carried out by adopting a solid state heating mode (for example, the microwave can be heated to more than 70 ℃ in about 3 minutes), the phenomenon of glue production in advance possibly caused by heating in water is avoided, the procedures of pH value adjustment, acid/alkali addition during enzyme deactivation, water washing and neutralization can be avoided, and the production cost and time are saved;
step five, post-treatment: the leather after enzyme deactivation and passivation is processed by glue boiling, purification, concentration and drying to obtain the finished product of the gelatin.
In a preferred embodiment of the method for preparing leather gelatin by combining the alkaline method/acid method and the enzymatic method, in the first step, the width of the thin strip is 2-5mm, the length of the uncut part is 1-3mm, and the leather is preferably cut into uniform thin strips with the thickness equivalent to that of thinner leather.
In a preferred embodiment of the method for preparing leather gelatin by combining the alkaline method/acid method and the enzymatic method, in the third step, neutral protease is adopted as the protease, the dosage of the neutral protease is 100-300U/g, the dosage of the lipase is 60-180U/g, and the enzymolysis pH value is 6-9.
In a preferred embodiment of the method for preparing leather gelatin by combining the alkaline method/acid method and the enzymatic method, in the third step, the protease is alkaline protease, the dosage of the alkaline protease is 200-600U/g, the dosage of the lipase is 60-180U/g, and the enzymolysis pH value is 7-10.
In a preferred embodiment of the method for preparing the leather gelatin by the alkaline method/acid method and the enzymatic method, in the third step, the leather continuously enters a tunnel type heating box by a mesh belt conveyor to be subjected to temperature rise treatment, the heating box is subjected to one or more of microwave heating, infrared heating and hot air heating, and the high-temperature enzyme deactivation and passivation time is adjusted by the change of the mesh belt conveying speed.
In any of the above preferred embodiments of the method for preparing leather gelatin by combining alkaline/acid method and enzymatic method provided by the present invention, in the second step, the following steps may be further performed: and (3) adding the cut leather into a hydrochloric acid or sulfuric acid solution, adjusting the pH value of the solution to be 1-2, keeping the temperature at 5-25 ℃, treating for 10-24 hours, washing with water, and adjusting the pH value to the proper pH value required by enzymolysis in the third step.
Compared with the prior art, the method for preparing the leather gelatin by compounding the alkaline method/the acid method and the enzymatic method has the following beneficial effects: the invention obviously improves the efficiency of decomposing collagen into gelatin, greatly shortens the production period compared with the traditional alkali-method gelatin preparation, and can complete the whole process within 3-5 days; meanwhile, the efficiency of decomposing collagen into gelatin is improved, and the sol phenomenon of the thin skin and the surface layer of the skin material is reduced, so that the gelatin yield is improved by more than 8 percent compared with the traditional alkaline method; the quality of the gelatin is also obviously improved, the freezing force of the gelatin prepared by the method can be improved by more than 10 percent due to the characteristics of the gelatin, and the transparency of the gelatin is improved by more than 6 percent.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:
FIG. 1 is a process flow diagram of a method for preparing leather gelatin by combining an alkaline method/an acid method and an enzymatic method provided by the invention;
fig. 2 is a diagram showing changes of the leather in the leather slitting process in the method for preparing leather gelatin by combining the alkaline method/acid method and the enzymatic method.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
Please refer to the process shown in the attached figure 1 of the specification: the leather material is cleaned and cut into thin strips with the width of about 2mm, the strips are kept to be not cut at the length of 2mm at intervals of 10cm, and the strips are longitudinally and transversely cut into leather blocks with the length of about 15 x 15cm, as shown in figure 2.
And (3) adding the cut leather into a sodium hydroxide solution, adjusting the pH value of the solution to 13.4, soaking for 3 days at the temperature of 20 ℃, washing with water, and adjusting the pH value to 9.5-10.
And transferring the leather into an enzymolysis tank I, adding lipase and alkaline protease for enzymolysis, wherein the enzymolysis temperature is 40 ℃, the pH value is controlled to be 7-8, the dosage of the lipase is 120u/g, and the dosage of the alkaline protease is 400 u/g. During enzymolysis, the leather and water are pumped out together by a pump, the leather is conveyed to a double-rod squeezer for dehydration treatment through a water filtering belt, the linear pressure is controlled to be 40kN/m, the water filtered and squeezed and extruded enters a second enzymolysis tank, the dewatered leather also enters the second enzymolysis tank for water absorption, and the leather is extracted from the second enzymolysis tank and is beaten to the first enzymolysis tank after no leather exists in the first enzymolysis tank, so that the leather is circularly squeezed. After 2 hours of treatment, the strength of the leather is obviously reduced, the surface is smooth, and the leather after being pressed and dehydrated is conveyed into a microwave box by a conveyor belt and heated to 90 ℃ to inactivate enzyme for 5 minutes.
And finally, obtaining the gelatin finished product through the processes of boiling, concentrating and drying.
Example two
Referring to the process shown in figure 1 of the specification: the leather material is cleaned and cut into thin strips with the width of about 2mm, the strips are kept to be not cut at the length of 3mm at intervals of 10cm, and the strips are cut into leather blocks with the length of 15 x 15cm in the longitudinal and transverse directions, as shown in figure 2.
Adding the cut leather into a sodium hydroxide solution, adjusting the pH value of the solution to 13.4, soaking for 3 days at the temperature of 20 ℃, washing with water, and adjusting the pH value to 7-8.
Transferring the leather into an enzymolysis tank I, adding lipase and neutral protease for enzymolysis, wherein the enzymolysis temperature is 45 ℃, the pH value is controlled to be 7-8, the dosage of the lipase is 100u/g, and the dosage of the neutral protease is 200 u/g. During enzymolysis, the leather and water are pumped out together by a pump, the leather is conveyed to a double-rod squeezer for dehydration treatment through a water filtering belt, the linear pressure is controlled at 60kN/m, the water filtered and squeezed and extruded enters a second enzymolysis tank, the dewatered leather also enters the second enzymolysis tank for water absorption, and the leather is extracted from the second enzymolysis tank and is beaten to the first enzymolysis tank after no leather exists in the first enzymolysis tank, so that the leather is circularly squeezed. After 2 hours of treatment, the strength of the leather is obviously reduced, the surface is smooth, and the leather after being pressed and dehydrated is conveyed into a microwave box by a conveyor belt and heated to 80 ℃ to inactivate enzyme for 8 minutes.
And finally, obtaining the finished product of the gelatin through the processes of glue boiling, concentration and drying.
EXAMPLE III
Please refer to the process shown in the attached figure 1 of the specification: the leather material is cleaned and cut into thin strips with the width of about 3mm, the strips are kept to be not cut at the length of 2mm at intervals of 12cm, and the strips are cut into leather blocks with the length of 20 x 15cm in the longitudinal and transverse directions, as shown in the attached figure 2.
Adding the cut leather into a hydrochloric acid solution, adjusting the pH value of the solution to 1.0, soaking for 12 hours at the temperature of 20 ℃, washing with water, and adjusting the pH value to 9-10.
And transferring the leather into an enzymolysis tank I, adding lipase and alkaline protease for enzymolysis, wherein the enzymolysis temperature is 40 ℃, the pH value is controlled to be 9-10, the dosage of the lipase is 150u/g, and the dosage of the alkaline protease is 400 u/g. During enzymolysis, the leather and water are pumped out together by a pump, the leather is conveyed to a double-rod squeezer for dehydration treatment through a water filtering belt, the linear pressure is controlled at 60kN/m, the water filtered and squeezed and extruded enters a second enzymolysis tank, the dewatered leather also enters the second enzymolysis tank for water absorption, and the leather is extracted from the second enzymolysis tank and is beaten to the first enzymolysis tank after no leather exists in the first enzymolysis tank, so that the leather is circularly squeezed. After 2 hours of treatment, the strength of the leather is obviously reduced, the surface is smooth, and the leather after being pressed and dehydrated is sent into an infrared heating box by a conveyor belt to be heated to 80 ℃ for deactivation of enzyme and passivation for 8 minutes.
And finally, obtaining the gelatin finished product through the processes of boiling, concentrating and drying.
Example four
Please refer to the process shown in the attached figure 1 of the specification: the leather material is cleaned and cut into thin strips with the width of about 3mm, the strips are kept to be not cut at the length of 2mm at intervals of 15cm, and the strips are cut into leather blocks with the length of 20 x 20cm in the longitudinal and transverse directions, as shown in the attached figure 2.
Adding the cut leather into a hydrochloric acid solution, adjusting the pH value of the solution to 1.0, soaking for 12 hours at the temperature of 20 ℃, washing with water, and adjusting the pH value to 7-8.
Transferring the leather into an enzymolysis tank I, adding lipase and neutral protease for enzymolysis, wherein the enzymolysis temperature is 45 ℃, the pH value is controlled to be 7-8, the dosage of the lipase is 100u/g, and the dosage of the neutral protease is 200 u/g. During enzymolysis, the leather and water are pumped out together by a pump, the leather is conveyed to a double-rod squeezer for dehydration treatment through a water filtering belt, the linear pressure is controlled at 50kN/m, the water filtered and squeezed and extruded enters a second enzymolysis tank, the dewatered leather also enters the second enzymolysis tank for water absorption, and the leather is extracted from the second enzymolysis tank and is beaten to the first enzymolysis tank after no leather exists in the first enzymolysis tank, so that the leather is circularly squeezed. After 3 hours of treatment, the strength of the leather is obviously reduced, the surface is smooth, and the leather after being pressed and dehydrated is sent into a hot air box by a conveyor belt to be heated to 90 ℃ for 5 minutes of enzyme deactivation and passivation.
And finally, obtaining the finished product of the gelatin through the processes of glue boiling, concentration and drying.
The comparison of the above examples with conventional alkaline and conventional acid processes is shown in the following table:
| categories | Consumption of raw materials (t) | Freeze power (Bloom g) | En's viscosity (E degree) | Transparency (mm) |
| Traditional alkaline process | 8.0 | 246 | 8.1 | 414 |
| Example one | 7.1 | 283 | 9.6 | 468 |
| Example two | 7.2 | 294 | 9.3 | 459 |
| Traditional acid process | 7.2 | 252 | 4.6 | 426 |
| Practice to | 6.9 | 291 | 5.8 | 465 |
| Example four | 6.8 | 298 | 6.2 | 471 |
As can be seen from the above table: by adopting the method for preparing the gelatin, the consumption of the leather is reduced, and is particularly obvious compared with the traditional alkaline method, and the consumption can reach more than 10 percent; the quality of the gelatin is also obviously improved, the viscosity, the freezing force and the transparency of the gelatin prepared by the method are improved to different degrees, and the process quality stability is good; meanwhile, the problem that the quality of the gelatin is affected because the freezing force of a finished gelatin product is seriously reduced because the enzymolysis degree is difficult to quickly determine and excessive enzymolysis is easily caused in the single enzyme method is solved.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention. The invention relates to the technical field of elevators, in particular to a special friction liner for a kilometer deep well.
Claims (6)
1. A method for preparing leather gelatin by combining an alkaline method/an acid method and an enzymatic method is characterized by comprising the following steps: the method comprises the following steps:
step one, cutting a leather material: cutting the cleaned whole leather into strips along one direction, wherein the width of each strip is close to the thickness of the thinner leather, the parts are not cut at intervals of 5-20cm during the cutting, and the leather is longitudinally and transversely cut into a plurality of pieces after being cut;
step two, leather pretreatment: adding the cut leather into a sodium hydroxide solution, adjusting the pH value of the solution to be kept between 13 and 13.5, keeping the temperature between 15 and 25 ℃, treating for 2 to 5 days, washing with water, and adjusting the pH value to the proper pH value required by enzymolysis in the third step;
step three, circular squeezing enzymolysis: transferring the pretreated leather into an enzymolysis container, adding lipase and protease for enzymolysis, and controlling the enzymolysis temperature at 30-55 ℃;
pumping out the leather and water together by using a pump during enzymolysis, separating the water from the leather after water filtration, allowing the leather to enter a roller press for squeezing and dewatering treatment, adjusting the line pressure of squeezing to be 20-80kN/m according to the state of the leather, returning the leather to an enzymolysis container after dewatering to absorb an enzyme-containing aqueous solution, circulating in such a way, and separating the leather from the water after the leather is subjected to enzymolysis treatment until the strength of the leather is obviously reduced, the surface is smooth and clean, and subcutaneous tissues are removed;
step four, inactivating enzyme and passivating: rapidly heating the leather material with the water separated out to perform enzyme deactivation and passivation treatment, wherein the enzyme deactivation temperature is not lower than 70 ℃;
step five, post-treatment: the leather after enzyme deactivation and passivation is processed by glue boiling, purification, concentration and drying to obtain the finished product of the gelatin.
2. The method for preparing leather gelatin by the combination of the alkaline method/acid method and the enzymatic method according to claim 1, which is characterized in that: in the first step, the width of the thin strip is 2-5mm, and the length of the part which is not cut off is 1-3 mm.
3. The method for preparing leather gelatin by the combination of the alkaline method/acid method and the enzymatic method according to claim 1, which is characterized in that: in the third step, the protease adopts neutral protease, the dosage of the neutral protease is 100-300U/g, the dosage of the lipase is 60-180U/g, and the enzymolysis pH value is 6-9.
4. The method for preparing leather gelatin by the combination of the alkaline method/acid method and the enzymatic method according to claim 1, which is characterized in that: in the third step, the protease adopts alkaline protease, the dosage of the alkaline protease is 200-600U/g, the dosage of the lipase is 60-180U/g, and the enzymolysis pH value is 7-10.
5. The method for preparing leather gelatin by the combination of the alkaline method/acid method and the enzymatic method according to claim 1, which is characterized in that: in the third step, leather materials continuously enter a tunnel type heating box by adopting a mesh belt conveying device for heating treatment, the heating box adopts one or more of microwave heating, infrared heating and hot air heating for combination, and the high-temperature enzyme deactivation and passivation time is adjusted by the change of the mesh belt conveying speed.
6. The method for preparing leather gelatin by the combination of the alkaline method/acid method and the enzymatic method according to any one of claims 1 to 5, which is characterized in that: in the second step, the following steps may be further performed: adding the cut leather into a hydrochloric acid or sulfuric acid solution, adjusting the pH value of the solution to be kept at 1-2, keeping the temperature at 5-25 ℃, treating for 10-24 hours, washing with water, and adjusting the pH value to the proper pH value required by enzymolysis in the third step.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210495079.4A CN114891446A (en) | 2022-05-07 | 2022-05-07 | Method for preparing leather gelatin by compounding alkaline method/acid method and enzymatic method |
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| CN1048232A (en) * | 1990-08-14 | 1991-01-02 | 王润成 | The cladding enzyme process prepares the processing method of edible Gelatinum oxhide |
| CN1059082A (en) * | 1991-09-19 | 1992-03-04 | 王润成 | Chromed tanned leather waste material enzyme process prepares the process of edible gelatin |
| WO2007119467A1 (en) * | 2006-03-23 | 2007-10-25 | Cosmed Pharmaceutical Co., Ltd. | Percutaneous absorption promoting agent and percutaneous absorption preparation using the same |
| CN103333939A (en) * | 2013-03-21 | 2013-10-02 | 新疆艾萨尔生物科技股份有限公司 | Method for preparing gelatin from bone collagen fibers by alkali-enzyme composite degradation |
| CN108676502A (en) * | 2018-04-12 | 2018-10-19 | 山东双圆生物科技有限公司 | A method of preparing gelatin using compound bio organic acid and compound biological enzyme |
| CN109329886A (en) * | 2018-10-29 | 2019-02-15 | 海南职业技术学院 | A kind of production method of edible glue |
| CN109354624A (en) * | 2018-12-06 | 2019-02-19 | 河北省微生物研究所 | The method that cattle hide gelatin is prepared using enzymatic treatment |
| CN112457781A (en) * | 2020-12-19 | 2021-03-09 | 河北省微生物研究所 | Method for extracting gelatin from leather waste leather scraps by enzymolysis |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1048232A (en) * | 1990-08-14 | 1991-01-02 | 王润成 | The cladding enzyme process prepares the processing method of edible Gelatinum oxhide |
| CN1059082A (en) * | 1991-09-19 | 1992-03-04 | 王润成 | Chromed tanned leather waste material enzyme process prepares the process of edible gelatin |
| WO2007119467A1 (en) * | 2006-03-23 | 2007-10-25 | Cosmed Pharmaceutical Co., Ltd. | Percutaneous absorption promoting agent and percutaneous absorption preparation using the same |
| CN103333939A (en) * | 2013-03-21 | 2013-10-02 | 新疆艾萨尔生物科技股份有限公司 | Method for preparing gelatin from bone collagen fibers by alkali-enzyme composite degradation |
| CN108676502A (en) * | 2018-04-12 | 2018-10-19 | 山东双圆生物科技有限公司 | A method of preparing gelatin using compound bio organic acid and compound biological enzyme |
| CN109329886A (en) * | 2018-10-29 | 2019-02-15 | 海南职业技术学院 | A kind of production method of edible glue |
| CN109354624A (en) * | 2018-12-06 | 2019-02-19 | 河北省微生物研究所 | The method that cattle hide gelatin is prepared using enzymatic treatment |
| CN112457781A (en) * | 2020-12-19 | 2021-03-09 | 河北省微生物研究所 | Method for extracting gelatin from leather waste leather scraps by enzymolysis |
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