A drying process for large bore ndxc type collagen casing extrusion

Abstract

This invention provides a drying process for extruding large-diameter NDXC type collagen casings, relating to the field of casing preparation technology. The drying process for extruding large-diameter NDXC type collagen casings includes the following steps: washing and drying cowhide, cutting it into pieces to obtain material blocks; subjecting the material blocks to alkali and acid immersion treatments, adding water to form a slurry, and sieving to obtain a slurry; adding a crosslinking agent, chitosan, and glycerol to the slurry, stirring until homogeneous, to obtain collagen aggregates; the crosslinking agent is a compound of glutaraldehyde and sodium alginate oxide; extruding the collagen aggregates through a ring nozzle to form a tubular membrane, spraying with glutaraldehyde, pre-drying, and segmented drying to obtain casings; the pre-drying involves low-temperature drying followed by spraying the surface of the tubular membrane with pure water at 5-7°C.

Description

Technical Field

[0001] This invention relates to the field of sausage casing preparation technology, and more specifically to a drying process for extruding large-diameter NDXC type collagen sausage casings. Background Technology

[0002] Large-diameter collagen casings are key packaging materials for filling coarse-diameter meat products such as red sausages, ham sausages, and luncheon meat. The drying process after extrusion has always been a core bottleneck restricting production capacity and quality.

[0003] From the perspective of existing technology, the main technical challenges in the production of large-diameter collagen casings lie in controlling drying uniformity and quality stability. Improper drying conditions can lead to significant product quality defects; excessively long drying times can cause the casings to become brittle, while excessively high humidity can soften them. Both of these issues directly affect the product's appearance, taste, and performance. During the drying process, uneven moisture distribution can cause differences in transverse and longitudinal properties, with thermal shrinkage exhibiting different characteristics in the transverse and longitudinal directions. This presents a process matching challenge for subsequent filling and processing. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an improved drying process for large-diameter NDXC type collagen casing extrusion: A drying process for extruding large-diameter NDXC type collagen casings includes the following steps: S1. Wash and dry the cowhide, then cut it into pieces to obtain material blocks; S2. The material blocks are subjected to alkali leaching and acid leaching treatment, water is added to make pulp, and the pulp is sieved to obtain slurry; S3. Add cross-linking agent, chitosan and glycerin to the gel, stir well to obtain collagen groups; The crosslinking agent is a compound of glutaraldehyde and sodium alginate oxide; S4. Extrude the collagen clusters through a ring nozzle to form a tubular membrane, spray with glutaraldehyde, pre-dry, and dry in stages to obtain the casing. The pre-drying process involves low-temperature drying followed by spraying the surface of the tubular membrane with pure water at 5-7°C.

[0005] Preferably, the alkaline leaching in step S2 involves immersing the material block in an excess of 0.3 mol / L sodium hydroxide solution for 1-2 days and then washing it with water until neutral. The acid leaching involves immersing the alkaline-treated material block in an excess of 0.3 mol / L hydrochloric acid solution for 4-6 hours and then washing it with water until neutral.

[0006] Preferably, the amount of water added in step S2 is 7-8 times the mass of the material block, and the material is passed through a 40-mesh sieve.

[0007] Preferably, in step S3, the volume ratio of glutaraldehyde to sodium alginate in the crosslinking agent is 1:3-5, the amount of crosslinking agent added is 0.5wt%, the amount of glycerol added is 6wt%, and the amount of chitosan added is 0.4wt%.

[0008] Preferably, the low-temperature drying in step S4 is carried out for 5-6 hours under conditions of relative humidity of 25-30% and temperature of 20-30°C. The segmented drying process involves first drying at 30-45℃ for 12-14 hours, then refrigerating at 2-4℃ for 4-5 hours, and finally drying at room temperature for 13-15 hours under conditions of 50-60% relative humidity and 70-80℃.

[0009] Preferably, the diameter of the annular nozzle in step S4 is 30-50 mm, and after spraying glutaraldehyde, excess glutaraldehyde on the surface of the tubular membrane is washed away.

[0010] This invention provides a drying process for extruding large-diameter NDXC type collagen casings, which has the following advantages compared with the prior art: This method adds a crosslinking agent, which is a compound of glutaraldehyde and sodium alginate, to the adhesive, which can improve the mechanical properties of the casing. At the same time, the drying steps of the casing are controlled. After low-temperature drying, it is sprayed with low-temperature pure water and then dried in stages. Based on the improvement of the crosslinking agent, the membrane shrinkage rate is further improved, and the stability of the casing after boiling is improved. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0012] Unless otherwise specified, all reagents used in the following schemes are commercially available products.

[0013] Preparation of sodium alginate oxide: Take a 5% sodium alginate solution, add anhydrous ethanol at a volume ratio of 1:3, add sodium periodate solution (dissolve sodium periodate at a mass ratio of 1:3 with 50 ml of deionized water), let stand for 24 h, then wash with anhydrous ethanol until a white solid precipitates, dissolve the white solid with deionized water to prepare a 5% sodium alginate oxidized solution.

[0014] Example 1: A drying process for large-diameter NDXC type collagen casing extrusion: S1. Wash and dry 10kg of cowhide, cut it into pieces to obtain material blocks; S2. Soak the material blocks in an excess of 0.3 mol / L sodium hydroxide solution for 1 day, wash with water until neutral, soak the alkali-treated material blocks in an excess of 0.3 mol / L hydrochloric acid solution for 4 hours, wash with water until neutral, add 7 times the mass of pure water of the material blocks to make a pulp, and pass it through a 40-mesh sieve to obtain a slurry. S3. Add 0.5wt% of crosslinking agent (glutaraldehyde to sodium alginate volume ratio of 1:3) to the total mass of the gel, add 0.4wt% of chitosan and 6wt% of glycerol, stir well to obtain collagen aggregates. S4. Extrude the collagen clusters through a 30mm diameter annular nozzle to form a tubular membrane. Spray with glutaraldehyde and dry at 30% relative humidity and 20℃ for 6 hours. Spray the surface of the tubular membrane with pure water at 5℃ for 10 seconds, then dry at 30℃ for 12 hours. After that, refrigerate at 2℃ for 4 hours. After returning to room temperature, dry at 50% relative humidity and 80℃ for 15 hours to obtain the casing.

[0015] Example 2: A drying process for large-diameter NDXC type collagen casing extrusion: S1. Wash and dry 10kg of cowhide, cut it into pieces to obtain material blocks; S2. Soak the material blocks in an excess of 0.3 mol / L sodium hydroxide solution for 2 days, wash with water until neutral, soak the alkali-treated material blocks in an excess of 0.3 mol / L hydrochloric acid solution for 6 hours, wash with water until neutral, add 7 times the mass of pure water of the material blocks to make a pulp, and pass it through a 40-mesh sieve to obtain a slurry. S3. Add 0.5wt% of crosslinking agent (glutaraldehyde to sodium alginate volume ratio of 1:5) to the total mass of the gel, add 0.4wt% of chitosan and 6wt% of glycerol, stir well to obtain collagen aggregates. S4. Extrude the collagen clusters through a 50mm diameter annular nozzle to form a tubular membrane. Spray with glutaraldehyde and dry at 25% relative humidity and 30℃ for 5 hours. Spray the surface of the tubular membrane with pure water at 7℃ for 20 seconds, then dry at 45℃ for 12 hours. After that, refrigerate at 4℃ for 5 hours. After returning to room temperature, dry at 60% relative humidity and 70℃ for 13 hours to obtain the casing.

[0016] Comparative Example 1: This comparative example uses the same drying process as Example 1, except for step S3, which is as follows: S3. Add 0.5wt% of crosslinking agent (glutaraldehyde to sodium alginate volume ratio of 1:6) to the total mass of the gel, add 0.4wt% of chitosan and 6wt% of glycerol, stir well to obtain collagen aggregates.

[0017] Comparative Example 2: S4. The collagen molecules are extruded through a 30mm diameter annular nozzle to form a tubular film. Glutaraldehyde is sprayed onto the film, and it is dried for 6 hours at a relative humidity of 30% and a temperature of 20℃. Then, it is dried at 30℃ for 12 hours, followed by refrigeration at 2℃ for 4 hours. After returning to room temperature, it is dried for 15 hours at a relative humidity of 50% and a temperature of 80℃ to obtain the casing.

[0018] Comparative Example 3: S4. Extrude the collagen clusters through a 30mm diameter annular nozzle to form a tubular membrane. Spray with glutaraldehyde and dry for 6 hours at a relative humidity of 30% and a temperature of 20℃. Spray the surface of the tubular membrane with pure water at 5℃ for 10 seconds, then dry at 30℃ for 12 hours. After returning to room temperature, dry at a relative humidity of 50% and a temperature of 80℃ for 15 hours to obtain the casing.

[0019] Comparative Example 4: S4. The collagen molecules are extruded through a 30mm diameter annular nozzle to form a tubular film. Glutaraldehyde is sprayed onto the film, and it is dried at 30℃ for 12 hours. Then, it is refrigerated at 2℃ for 4 hours. After returning to room temperature, it is dried at 80℃ with a relative humidity of 50% for 15 hours to obtain the casing.

[0020] Detection: 1. Mechanical property testing The collagen casings prepared in Examples 1-2 and Comparative Examples 1-4 were cut into strips of 1cm × 5cm as test samples. After soaking in deionized water for 2 minutes, the samples were removed and clamped at both ends with an A / MTG probe, with an initial distance of 30mm between the upper and lower clamps. The tensile strength (TS) and elongation at break (EAB) of the test samples were calculated. The test results are shown in Table 1. Table 1 Mechanical property testing As can be seen from the data in Table 1, the mechanical property test results of Example 1 are better. Although the elongation at break in Comparative Example 1 is better than that in Example 2, its tensile strength is lower than that in Examples 1-2, and is 39.13% lower than that in Example 1.

[0021] 2. Membrane shrinkage rate determination The collagen casings prepared in Examples 1-2 and Comparative Examples 1-4 were cut into strips of 4cm×8cm as test samples. After boiling in boiling water for 2 minutes, they were taken out, and the residual moisture on the surface was gently absorbed with filter paper. The length (L) and width (d) after boiling were measured. The heat shrinkage rate of the transverse (TD) and longitudinal (MD) was calculated according to formulas (1) and (2). Three parallel samples were taken for each group, and the average value was taken.

[0022] TD = 4 - d / 4 × 100% (1) MD = 8 - L / 8 × 100% (2) Table 2. Measurement of membrane shrinkage rate As can be seen from the data in Table 2, the lateral and longitudinal shrinkage rates of Example 1 are both good.

[0023] 4. Sensory testing The collagen casings prepared in Examples 1-2 and Comparative Examples 1-4 were used as test samples, and their color and odor were scored. Ten randomly selected evaluators were invited to score the color and odor of the treated samples, using a 10-point scale. The average score was taken, and the scoring principles are shown in Table 3 below: Table 3 Sensory Rating Table The specific results are shown in Table 4: Table 4 Sensory Evaluation As can be seen from the data in Table 4, the color and odor of Example 1 are in line with market expectations. Although the color and odor of Comparative Examples 2-4 are also good, the mechanical properties and boiling resistance of Comparative Examples 2-4 are not as good as those of Example 1, based on the data in Tables 1 and 2.

[0024] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drying process for large bore NDXC type collagen casing extrusion, characterized in that, The drying process includes the following steps: S1. Wash and dry the cowhide, then cut it into pieces to obtain material blocks; S2. The material blocks are subjected to alkali leaching and acid leaching treatment, water is added to make pulp, and the pulp is sieved to obtain slurry; S3. Add cross-linking agent, chitosan and glycerin to the gel, stir well to obtain collagen groups; The crosslinking agent is a compound of glutaraldehyde and sodium alginate oxide; S4. The collagen clusters are extruded through a ring nozzle to form a tubular membrane, which is then sprayed with glutaraldehyde. The tubular membrane is pretreated and dried in sections to obtain the casing. The tubular membrane pretreatment involves low-temperature drying followed by spraying the surface of the tubular membrane with pure water at 5-7°C.

2. The drying process according to claim 1, characterized in that, The alkaline leaching in step S2 involves immersing the material blocks in an excess of 0.3 mol / L sodium hydroxide solution for 1-2 days, followed by washing with water until neutral. The acid leaching involves immersing the alkaline-treated material blocks in an excess of 0.3 mol / L hydrochloric acid solution for 4-6 hours, followed by washing with water until neutral.

3. The drying process of claim 1, wherein, The amount of water added in step S2 is 7-8 times the mass of the material block, and it is passed through a 40-mesh sieve.

4. The drying process of claim 1, wherein, In step S3, the volume ratio of glutaraldehyde to sodium alginate in the crosslinking agent is 1:3-5. Based on the total mass of the adhesive, the amount of crosslinking agent added is 0.5wt%, the amount of glycerol added is 6wt%, and the amount of chitosan added is 0.4wt%.

5. The drying process of claim 1, wherein, The low-temperature drying described in step S4 is carried out under conditions of relative humidity of 25-30% and temperature of 20-30℃ for 5-6 hours, followed by pure water spraying for 10-20 seconds. The segmented drying process involves first drying at 30-45℃ for 12-14 hours, then refrigerating at 2-4℃ for 4-5 hours, and finally drying at room temperature for 13-15 hours under conditions of 50-60% relative humidity and 70-80℃.

6. The drying process of claim 1, wherein, The diameter of the annular nozzle mentioned in step S4 is 30-50mm. After spraying glutaraldehyde, excess glutaraldehyde on the surface of the tubular membrane is washed away.

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