High-strength collagen casing for boiled sausages and preparation method of high-strength collagen casing

Abstract

The invention relates to a high-strength collagen casing for boiled sausages and a preparation method of the high-strength collagen casing. Adding ammonium sulfate into a rotating hub, treating the washed split leather in the rotating hub, treating the split leather with citric acid and disodium citrate, and dicing the cow split leather; the cow leather particles and water are prepared into a mixture, the mixture is ground through a high-speed grinding machine, a grinding auxiliary is added during grinding, and the retention rate after grinding is 1t; 5%; the collagen particles swell to form colloid; dispersing with a homogenizer; pumping the collagen colloid into a mixer, and adding a cross-linking agent into the mixer; extruding the mixed colloid by an extruder and then drying; and carrying out spray humidification treatment on the dried casing to adjust the moisture content, so as to obtain a casing winding product. The method has the advantages that effective grinding is carried out under the assistance of a proper grinding aid, so that the fineness of collagen fibers in the collagen grinding preparation process is effectively improved, the grinding frequency can be reduced, the fibers are refined, the strength of the fibers is not damaged, and the comprehensive performance of the casing is improved.

Description

Technical Field

[0001] The invention relates to the technical field of casing preparation, and in particular to a high-strength collagen casing for boiled sausages and a preparation method thereof. Background Art

[0002] The cowhide collagen fibers used in artificial sausage casings are protein molecules composed of triple helical polypeptide chains entangled with each other on a molecular scale. They are then biologically cross-linked with adjacent collagen molecules at specific positions to become higher-level microfibrils, fibrils, fibers, fiber bundles and even fibrous structures visible to the naked eye. This cross-linked hierarchical structure gives collagen a certain mechanical strength, making it a structural support unit of biological tissues.

[0003] The conventional "dry process" is used to prepare high-strength casings, which can be used to prepare boil-resistant sausages. The "dry process" is a casing production process in which the split hide of cattle is directly kneaded into a colloid through acid swelling, and then extruded and dried to form a finished product. The casings prepared by the conventional "wet process" have a better taste, but the production speed is slow and the strength is not high enough. The "wet process" is a casing production process in which the split hide of cattle is ground and pulped after initial acid swelling, and then further acidified and mixed to form a colloid. After the colloid is extruded into a crude casing, it is first soaked in a coagulation liquid for dehydration, and then further dried to form a finished product.

[0004] Although the casings prepared by the existing dry method have high strength, the sausages prepared by using the casings have a poor taste after being boiled; the sausages prepared by the existing wet method have a tender taste, and the fibers can be refined by repeated grinding, but the fibers may be damaged, degraded and broken due to excessive processing, resulting in insufficient casing strength and low production efficiency. Especially in the case of challenging casing tube length and inner diameter, the problems of insufficient strength and low production efficiency are more obvious. The present invention provides a high-strength collagen casing for boiled sausages and a preparation method thereof, which ensures the strength of the casing during sausage production while taking into account the taste of the sausage after boiling. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a high-strength collagen casing for boiled sausages and a preparation method thereof, which can solve the problems in the prior art that casings prepared by a dry method have a poor taste after being boiled in water, and casings prepared by a wet method have insufficient strength and low production efficiency.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: comprising the following steps: S1. Wash the cowhide and separate the cowhide into two layers on a splitting machine; S2, adding ammonium sulfate to the rotating hub, treating the washed split leather in the rotating hub for 2 hours, draining and re-adding ammonium sulfate solution, emptying and washing after rotating for 2 hours, and then treating the split leather with citric acid and disodium citrate, rotating for 16 hours, adjusting the solution pH value every hour to maintain it at 4.6, after the treatment period, washing the split leather for 4 hours, and granulating the treated cow split leather into particles of 0.5-1 cm in size; S3, mixing cowhide particles with water into a mixture, grinding with a high-speed grinder, adding a grinding aid during grinding, the grinding aid being a composite abrasive composed of Tween and Span, the HLB value of the composite abrasive being between 12-16.7, the pH value during grinding being 4-5, the grinding times being 1-3 times, and the cowhide collagen being ground into a pulpy fiber mass after grinding, and the retention rate at a sieve gap of 1 mm after grinding being <5%; S4, mixing the fibrous hydrated collagen from the high-speed grinder with an acidic solution, wherein the acidic solution is a hydrochloric acid-glycerol-water mixture, and the collagen particles swell to form a colloid; S5. After the colloid is stored for 18-24 hours, it is pumped to a homogenizer for dispersion. The homogenizer is equipped with a two-stage valve with a pressure drop of 1500psi at each stage. S6, the obtained collagen colloid is filtered and pumped to a mixer in front of an extruder, and a cross-linking agent, glutaraldehyde, is added to the mixer; S7, the mixed colloid enters the casing track through the extruder for hot air drying, and the casing diameter is adjusted by using extruders with different extrusion diameters; S8. The dried casings are treated with spray humidification to adjust the moisture content, so as to obtain casing winding products that meet the size and strength requirements.

[0007] Furthermore, the grinding aid is 100-1000 ppm, the Tween is one of Tween 20, Tween 40, Tween 60, and Tween 80, and the Span is one of Span 20, Span 40, Span 60, and Span 80.

[0008] Furthermore, in step S1, when cleaning the cowhide, water is added to the wooden hub, and then hydrated lime and sodium sulfide are added, the amount of hydrated lime added is 3%-4% of the mass of the cowhide, and the amount of sodium sulfide added is 2.5%-3% of the mass of the cowhide. The hub is run for 15 hours, and then allowed to stand for 9 hours and then drained, and then washed with water for 15 minutes, and then 1.0% of the mass of the cowhide lime water is added, rotated for 5 minutes, and allowed to stand for 1 hour.

[0009] Furthermore, in step S2, when washing the split leather, the split leather is added into a wooden hub, the mass of water in the wooden hub is 1.5-2 times the mass of the split leather, and the cowhide is washed in the hub at a flow rate of 150 liters per minute for 30 minutes; the amount of ammonium sulfate added is 0.5% of the mass of the split leather; after washing for 2 hours, the split leather is emptied and washed for 3 hours at a flow rate of 150 liters per minute; The amount of citric acid added is 0.6%-0.07% of the weight of the split leather, and the amount of disodium citrate added is 0.9%-1% of the weight of the split leather; After the treatment period, the citrate solution was drained and the splits were washed at a flow rate of 150 liters per minute.

[0010] Furthermore, in the step S3, the mass ratio of the cowhide particles to water is 1:2-3; in the step S4, in the acidic solution, the hydrochloric acid concentration is 31%, the volume ratio of hydrochloric acid to glycerol is 9:10, and the mass of glycerol is 6%-7% of the mass of water; in the step S6, dye is added to the mixer to prepare colored casings; in the step S7, the drying speed and degree are controlled by the hot air temperature, humidity, air volume, colloid extrusion and casing winding speed.

[0011] The invention discloses a collagen casing prepared by a method for preparing a high-strength collagen casing for boiled sausages.

[0012] The advantages of the present invention are: effective grinding is performed with the assistance of a suitable grinding aid, and the grinding aid adjusts the HLB value by combination, so as to obtain a better dispersion and stabilization effect on collagen, effectively improve the fineness of collagen fibers in the collagen grinding preparation process, reduce the number of grinding times, and achieve both fiber refinement and fiber strength without damage, thereby improving the comprehensive performance of the casing. On the one hand, the bonding degree of collagen fibers before boiling can be enhanced to meet the tolerance of the casing during high-speed filling and low-temperature cooking in sausage production, and on the other hand, a certain degree of fiber disintegration can be induced during boiling, thereby bringing a crisp and tender taste. Repeated grinding and homogenization under normal conditions will damage the refined fibers. After adding the grinding aid, it has a similar effect to a sealant on the newly formed chemical groups on the fiber surface, effectively inhibiting the re-bonding of the ground fibers through the interaction of chemical groups, improving the grinding efficiency, reducing the side effects of repeated grinding, and maintaining the integrity of the fibers. After drying, the moisture between the fiber molecules is removed, the distance between the newly formed chemical groups of the fibers becomes closer, and the interaction is restored. At the same time, the overall mechanical strength is improved because the number of groups interacting between the ground fibers increases. After secondary cooking such as boiling, the interaction between the chemical groups of the disintegrated fibers is weakened again by the emulsifier, which reduces the strength of the casing and makes the taste tender. Through the pulping and grinding of collagen, the crude fibers are torn apart and ground, and the interactions between the fibers through hydrogen bonds and ionic bonds are fully exerted under swelling. Further homogenization makes the interactions more evenly dispersed in the colloid, and the weak areas are further eliminated, which is beneficial to the orientation of the fibers during subsequent extrusion. The strength that the originally unevenly distributed crude fibers only have in thicker cases is obtained with a thinner thickness. High-speed extrusion gives the fibers a stronger orientation and higher strength. After the thinner casings are made into sausages and steamed, the casing fibers can be more fully restored to the hydrated and swollen state before drying, the hydrogen bonds and ionic bonds are weakened, and the taste becomes tender. DETAILED DESCRIPTION

[0013] In order to make the purpose, technical scheme and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with specific implementation methods. The following examples can enable technicians in this field to understand the present invention more comprehensively, but the present invention is not limited to the scope of the embodiments.

[0014] This specific implementation adopts the following technical solution: a collagen casing is prepared by a preparation method of a high-strength collagen casing for boiled sausages.

[0015] A method for preparing a high-strength collagen casing for boiled sausages comprises the following steps: S1. Washing cowhide: When washing cowhide, add water to the wooden hub, then add hydrated lime and sodium sulfide. The amount of hydrated lime added is 3%-4% of the weight of the cowhide, and the amount of sodium sulfide added is 2.5%-3% of the weight of the cowhide. The hub runs for 15 hours, then stands for 9 hours and then drains the water. Then wash with water for 15 minutes, then add 1.0% of the weight of the cowhide in lime water, rotate for 5 minutes, stand for 1 hour, and separate the washed cowhide into the dermis (second layer of leather) on a leather splitting machine.

[0016] S2, washing the split leather, adding the split leather into a wooden hub, the mass of water in the wooden hub is 1.5-2 times the mass of the split leather, washing the cowhide in the hub at a flow rate of 150 liters per minute for 30 minutes; adding ammonium sulfate into the hub, the amount of ammonium sulfate added is 0.5% of the mass of the split leather, treating the washed split leather in the hub for 2 hours, draining and re-adding ammonium sulfate solution, emptying and washing after 2 hours, washing at a flow rate of 150 liters per minute for 3 hours, and then The split leather is treated with citric acid and disodium citrate, with the citric acid added in an amount of 0.6%-0.07% of the split leather's mass and the disodium citrate added in an amount of 0.9%-1% of the split leather's mass. The leather is washed for 16 hours, and the pH value of the solution is adjusted every hour to maintain it at 4.6. After the treatment period, the citrate solution is drained and the split leather is washed at a flow rate of 150 liters per minute for 4 hours. The cow split leather treated as above is diced into particles of 0.5-1 cm in size.

[0017] S3. Prepare a mixture of cowhide particles and water in a mass ratio of 1:2-3, grind with a high-speed grinder, add a grinding aid during grinding, the grinding aid is a composite abrasive composed of Tween and Span, Tween is one of Tween 20, Tween 40, Tween 60, Tween 80, Span is one of Span 20, Span 40, Span 60, Span 80, the HLB value of the composite abrasive is between 12-16.7, the grinding aid is 100-1000ppm, the pH value during grinding is 4-5, the number of grindings is 1-3 times, and the cowhide collagen forms a slurry of fiber agglomerates after grinding, and the retention rate at a sieve gap of 1mm after grinding is <5%.

[0018] S4. Mix the fibrous hydrated collagen from the high-speed grinder with an acidic solution, which is a hydrochloric acid-glycerol-water mixture. In the acidic solution, the hydrochloric acid concentration is 31%, the volume ratio of hydrochloric acid to glycerol is 9:10, and the mass of glycerol is 6%-7% of the mass of water. The collagen particles swell to form a colloid.

[0019] S5. After the colloid is stored for 18-24 hours, it is pumped to a homogenizer for dispersion. The homogenizer is equipped with a two-stage valve with a pressure drop of 1500psi at each stage.

[0020] S6. The obtained collagen colloid is filtered and then pumped to a mixer in front of an extruder. A cross-linking agent, glutaraldehyde, and a dye are added to the mixer to prepare a colored casing.

[0021] S7. The mixed colloid enters the casing track through the extruder for hot air drying. The drying speed and degree are controlled by the hot air temperature, humidity, air volume, colloid extrusion and casing winding speed. The casing diameter is adjusted by extruders with different extrusion diameters.

[0022] S8. The dried casings are treated with spray humidification to adjust the moisture content, so as to obtain casing winding products that meet the size and strength requirements.

[0023] Embodiment 1: After cutting, fresh cowhide is washed and soaked in municipal water at 16°C overnight, then fleshed and weighed. 3300 kg of water and 1270 kg of fleshed cowhide are added to a 5 cubic wooden hub, followed by 41.5 kg of hydrated lime and 32 kg of sodium sulfide. The hub is run for 15 hours, then allowed to stand for 9 hours and then drained. It is then washed with municipal water for 15 minutes, 1.0% lime water is added, rotated for 5 minutes, allowed to stand for 1 hour, and the washed cowhide is separated into the dermis (second layer of leather) on a skin splitter. The dermis is further processed to prepare collagen for extrusion.

[0024] 2600 kg of the split hide prepared as above and 5000 liters of water are added to a 16 cubic wooden hub. The cow hide is washed in the hub at a flow rate of 150 liters per minute for 30 minutes. The washed split hide is treated in a hub filled with 5000 liters of water containing 13 kg of ammonium sulfate for 2 hours, drained and the ammonium sulfate solution is added again. After washing for 2 hours, the hub is emptied and washed for 3 hours at a flow rate of 150 liters per minute. After draining, the leather is treated with 5000 liters of water containing 18 kg of aqueous citric acid and 24.5 kg of disodium citrate. The hub is washed for 16 hours, and the pH value of the solution is adjusted every hour to maintain it at 4.6. After the treatment period, the citrate solution is emptied and the split hide is washed for 4 hours at a flow rate of 150 liters per minute. The cow split hide treated as above is diced into particles of about 0.5-1 cm in size.

[0025] A mixture of 110 kg of cowhide particles (30 kg of solids) and 270 liters of 14°C water is ground in a high-speed grinder. A grinding aid is added during grinding. The grinding aid is a composite abrasive composed of Tween 20 and Span 20. The HLB value of the composite abrasive is 16, and the grinding aid is 500 ppm. The pH value during grinding is 4-5. After grinding once, the cowhide collagen forms a slurry of fiber agglomerates. In a stainless steel tank, a solution of 4.5 liters of 31% hydrochloric acid, 5 liters of glycerol and 100 kg of water is prepared. The cowhide slurry from the high-speed grinder and the acid-glycerol-water mixture are pumped into the storage tank at equal flow rates through a mixer. When the fibrous hydrated collagen is mixed with the acidic solution, the collagen particles will swell to form a colloid.

[0026] After being stored for 18 to 24 hours, the colloid is pumped to a homogenizer for dispersion. The homogenizer is equipped with a two-stage valve with a pressure drop of 1500psi at each stage. The homogenized mixture is pumped into a storage tank and degassed in a vacuum. The collagen colloid obtained is filtered and pumped to a mixer in front of an extruder. The strength of the collagen casing is adjusted by adding a cross-linking agent, glutaraldehyde, to the mixer. The amount of glutaraldehyde added is 0.2% of the weight of the collagen. Dyes can also be added to prepare colored casings. The colloid enters the casing track through the extruder for hot air drying. The casing caliber can be adjusted by using extruders with different extrusion calibers. The casing caliber prepared in Example 1 is 28mm. The drying speed and degree can be controlled by hot air temperature, humidity, air volume, and colloid extrusion and casing winding speed. The dried casing is adjusted to have a moisture content by spray humidification treatment to obtain a casing winding product that meets the size and strength requirements.

[0027] Embodiment 2: The other preparation steps of Example 2 are the same as those of Example 1, except that the grinding process is repeated three times.

[0028] Comparative Example 1: The other preparation steps of Comparative Example 1 are the same as those of Example 1, except that no grinding aid is added during the grinding process.

[0029] Comparative Example 2: The other preparation steps of Comparative Example 2 are the same as those of Example 1, except that no grinding aid is added during the grinding process, and the grinding process is repeated three times.

[0030] The casings prepared in Examples 1 and 2 and Comparative Examples 1 and 2 were subjected to the measurement of the average longitudinal breaking strength, and the corresponding casings were used to prepare sausages and then the average texture analyzer puncture force was measured. The measurement results are shown in Table 1.

[0031] Table 1: The average longitudinal breaking force measurement results of the casings prepared in Examples 1 and 2 and Comparative Examples 1 and 2, and the average puncture force measurement results of the corresponding casings after preparing sausages Retention rate measurement: After 200 g of slurry is filtered through a 1 mm slit sieve, the filter residue is collected, dried and weighed, and its percentage of the solid content in the 200 g slurry is calculated. The average value is taken after three measurements.

[0032] Casing-longitudinal breaking strength measurement (SB / T10373-2012): (1) Instrument: Instron tensile testing machine; (2) Sampling: Cut a small strip of 120 mm × 15 mm (length × width) along the longitudinal direction of the casing as a sample, soak it in room temperature water for 5 min, take it out, and dry the surface with absorbent paper; (3) Measurement: Adjust the clamp distance of the tensile testing machine to 100 mm, clamp the casing sample prepared above in the chuck, and perform the tensile test at a speed of 100 mm / min±10 mm / min. If the casing breaks at the chuck, re-sample and test. Measure 10 samples in total, take the arithmetic mean of the 10 measured data, and calculate the mean square error.

[0033] Sausage-Texture Analyzer Puncture Force Measurement: (1) Instrument: TA-XT texture analyzer from Stable Micro Systems; (2) Sampling: Take three sausages with a length of 10-15 cm, equilibrate the temperature and humidity at room temperature, and make a 1 cm puncture point along the upper surface of each sausage; (3) Measurement: Use a 2 mm round needle to move downward from just above the sausage surface at a speed of 1 mm / s to about 1 cm from the surface, and then move downward at a speed of 2 mm / s. Set the trigger force to 15 g. After puncturing, reset the sausage upward at a speed of 10 mm / m / s. Move the sausage sideways for 1 cm and repeat the test 5 times. Change another sausage and repeat the measurement until 18 data are obtained. Take the arithmetic mean and calculate the mean square error.

[0034] From the above measurement results, it can be seen that compared with comparative examples 1 and 2, after adding the grinding aid, embodiments 1 and 2 can achieve the purpose of enhancing the longitudinal breaking resistance of the collagen casing with the same number of grinding times, and the texture analyzer puncture force of the sausage made by the prepared collagen casing is reduced, and the taste of the sausage becomes tender after steaming, and the number of grinding times is small, that is, the collagen casing can have a strong longitudinal breaking resistance, the texture analyzer puncture force of the sausage is reduced, the grinding effect is better, and the comprehensive performance of the casing is improved.

[0035] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a high-strength collagen casing for boiled sausages, characterized in that: The following steps are involved: S1. Wash the cowhide and separate the cowhide into two layers on a splitting machine; S2, adding ammonium sulfate to the rotating hub, treating the washed split leather in the rotating hub for 2 hours, draining and re-adding ammonium sulfate solution, emptying and washing after rotating for 2 hours, and then treating the split leather with citric acid and disodium citrate, rotating for 16 hours, adjusting the solution pH value every hour to maintain it at 4.6, after the treatment period, washing the split leather for 4 hours, and granulating the treated cow split leather into particles of 0.5-1 cm in size; S3, mixing cowhide particles with water into a mixture, grinding with a high-speed grinder, adding a grinding aid during grinding, the grinding aid being a composite abrasive composed of Tween and Span, the HLB value of the composite abrasive being between 12-16.7, the pH value during grinding being 4-5, the grinding times being 1-3 times, and the cowhide collagen being ground into a pulpy fiber mass after grinding, and the retention rate at a sieve gap of 1 mm after grinding being <5%; S4, mixing the fibrous hydrated collagen from the high-speed grinder with an acidic solution, wherein the acidic solution is a hydrochloric acid-glycerol-water mixture, and the collagen particles swell to form a colloid; S5. After the colloid is stored for 18-24 hours, it is pumped to a homogenizer for dispersion. The homogenizer is equipped with a two-stage valve with a pressure drop of 1500psi at each stage. S6, the obtained collagen colloid is filtered and pumped to a mixer in front of the extruder, and a cross-linking agent glutaraldehyde is added to the mixer; S7, the mixed colloid enters the casing track through the extruder for hot air drying, and the casing diameter is adjusted by using extruders with different extrusion diameters; S8. The dried casings are treated with spray humidification to adjust the moisture content, so as to obtain casing winding products that meet the size and strength requirements.

2. The method for preparing a high-strength collagen casing for boiled sausage according to claim 1, characterized in that: The grinding aid is 100-1000ppm, the Tween is one of Tween 20, Tween 40, Tween 60 and Tween 80, and the Span is one of Span 20, Span 40, Span 60 and Span 80.

3. The method for preparing a high-strength collagen casing for boiled sausage according to claim 1, characterized in that: In the step S1, when washing the cowhide, water is added to the wooden hub, and then hydrated lime and sodium sulfide are added, the amount of hydrated lime added is 3%-4% of the weight of the cowhide, and the amount of sodium sulfide added is 2.5%-3% of the weight of the cowhide. The hub is run for 15 hours, and then allowed to stand for 9 hours and then drained, and then washed with water for 15 minutes, and then 1.0% of the weight of the cowhide in lime water is added, rotated for 5 minutes, and allowed to stand for 1 hour.

4. The method for preparing a high-strength collagen casing for boiled sausage according to claim 1, characterized in that: In the step S2, when washing the split leather, the split leather is added into a wooden hub, the mass of water in the wooden hub is 1.5-2 times the mass of the split leather, and the cowhide is washed in the hub at a flow rate of 150 liters per minute for 30 minutes; the amount of ammonium sulfate added is 0.5% of the mass of the split leather; after washing for 2 hours, the split leather is emptied and washed for 3 hours at a flow rate of 150 liters per minute; The amount of citric acid added is 0.6%-0.07% of the weight of the split leather, and the amount of disodium citrate added is 0.9%-1% of the weight of the split leather; After the treatment period, the citrate solution was drained and the splits were washed at a flow rate of 150 liters per minute.

5. The method for preparing a high-strength collagen casing for boiled sausage according to claim 1, characterized in that: In the step S3, the mass ratio of cowhide particles to water is 1:2-3; in the step S4, in the acidic solution, the concentration of hydrochloric acid is 31%, the volume ratio of hydrochloric acid to glycerol is 9:10, and the mass of glycerol is 6%-7% of the mass of water; in the step S6, dye is added to the mixer to prepare colored casings; in the step S7, the drying speed and degree are controlled by hot air temperature, humidity, air volume, colloid extrusion and casing winding speed.

6. Collagen casings prepared by the method for preparing high-strength collagen casings for boiled sausages according to claim 1.

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