阅读说明：本技术 可食性肠衣及其制备方法 (Edible casing and preparation method thereof ) 是由 赵换英 宋立国 马龙 李智超 崔浩冉 于 2021-09-16 设计创作，主要内容包括：本发明属于食品加工技术领域,具体的涉及一种可食性肠衣及其制备方法。本发明所述的肠衣胶液,由以下原料组成：豌豆蛋白、海藻酸钠、甘油、辛癸酸甘油酯、谷氨酰胺转移酶、微晶纤维素、木质素、十二烷基硫酸钠和余量水；所述的交联剂包括乳酸钙、葡萄糖酸钙和戊二醛。本发明所述的可食性肠衣,选用豌豆蛋白和海藻酸钠为主要成膜物质,原料来源广泛,价格低廉,具有可降解性和可再生性,添加增塑剂、增强剂、十二烷基硫酸钠和TG酶等,对豌豆蛋白和海藻酸钠进行改性处理,使得制备的可食性肠衣的致敏性低,机械强度高,结构紧密,皮馅结合良好,质量稳定。(The invention belongs to the technical field of food processing, and particularly relates to an edible casing and a preparation method thereof. The casing glue solution provided by the invention comprises the following raw materials: pea protein, sodium alginate, glycerol, caprylic capric glyceride, transglutaminase, microcrystalline cellulose, lignin, sodium dodecyl sulfate and the balance of water; the cross-linking agent comprises calcium lactate, calcium gluconate and glutaraldehyde. The edible casing provided by the invention selects pea protein and sodium alginate as main film forming substances, has wide raw material sources, low price and degradability and renewability, and is modified by adding the plasticizer, the reinforcing agent, sodium dodecyl sulfate, TG enzyme and the like, so that the prepared edible casing has low allergenicity, high mechanical strength, compact structure, good skin and stuffing combination and stable quality.)

1. An edible casing, characterized in that: the sausage casing glue solution comprises the following raw materials in percentage by mass: pea protein 7.5-8.0%, sodium alginate 1.0-1.5%, glycerin 0.5-1.0%, caprylic/capric glyceride 1.5-2.0%, transglutaminase 0.25-0.45%, microcrystalline cellulose 0.5-0.8%, lignin 1.5-2.0%, sodium dodecyl sulfate 0.1-0.3% and balance water; the cross-linking agent comprises calcium lactate, calcium gluconate and glutaraldehyde.

2. An edible casing as claimed in claim 1, wherein: the sausage casing glue solution comprises the following raw materials in percentage by mass: pea protein 8.0%, sodium alginate 1.0%, glycerol 0.8%, caprylic capric acid glyceride 1.7%, transglutaminase (TG enzyme) 0.40%, microcrystalline cellulose 0.5%, lignin 1.5%, sodium dodecyl sulfate 0.3% and balance water.

3. A method of preparing an edible casing as claimed in claim 1, wherein: the method comprises the following steps:

(1) uniformly mixing glycerol, caprylic capric acid glyceride, transglutaminase and water to obtain a mixed solution, adding a mixture of pea protein, sodium alginate, microcrystalline cellulose, lignocellulose and sodium dodecyl sulfate into the mixed solution to form a glue solution, and chopping and mixing to form gel;

(2) extruding and molding the gel prepared in the step (1), spraying the outer wall of the casing with a mixed solution of calcium lactate and calcium gluconate, and spraying the inner wall of the casing with glutaraldehyde; after spraying, washing and drying the casing;

(3) shrinking the dried sausage casing, and dip-coating an oil-soluble solution on the outer wall of the sausage casing in the shrinking process;

(4) curing: firstly, aging at 45-50 ℃ for 0.5-1.0h, and then aging at 53-55 ℃ and relative humidity of 50-55% for 48-55h to prepare the edible casing.

4. A process for preparing an edible casing as claimed in claim 3, wherein: the chopping and mixing temperature in the step (1) is less than or equal to 15 ℃, and the chopping and mixing time is 30-40 min.

5. A process for preparing an edible casing as claimed in claim 3, wherein: stirring and vacuum degassing are carried out after chopping in the step (1), the vacuum degree is 0.1MPa, and the degassing time is 5-7 min.

6. A process for preparing an edible casing as claimed in claim 3, wherein: the extrusion molding speed in the step (2) is 20-50 m/min.

7. A process for preparing an edible casing as claimed in claim 3, wherein: when the inner wall spraying in the step (2) is just sprayed out of the casing head, capillary spraying is adopted at the machine head, glutaraldehyde is sprayed all the time along with the spraying of the casing, and the concentration of the glutaraldehyde is 0.02-0.05%. Cooling the glutaraldehyde solution by a pipeline, wherein the temperature of the cooling water is controlled to be 5-10 ℃;

when the outer wall spraying in the step (2) is just spraying out of the casing head, the casing head adopts radial spraying, mixed liquid of calcium lactate and calcium gluconate is sprayed all the time along with the spraying out of the casing, and the mass concentration of the mixed liquid of calcium salt is 25-30%, wherein: the mass ratio of calcium lactate to calcium gluconate is 2-3: 1.

8. A process for preparing an edible casing as claimed in claim 3, wherein: the mass concentration of the glutaraldehyde in the step (2) is 0.02-0.05%; the drying temperature of the sausage casing in the step (2) is 50-55 ℃, and the drying time is 20-25 min.

9. A process for preparing an edible casing as claimed in claim 3, wherein: the oil-soluble solution in the step (3) is a mixed solution of white oil and glycerol monooleate, wherein the mass ratio of the white oil to the glycerol monooleate is 1: 0.1-0.15.

10. A process for preparing an edible casing as claimed in claim 3, wherein: during the shrinkage in the step (3), the sausage casing is dipped in the oil-soluble solution through the sponge with oil, and the amount of the oil-soluble solution on the sponge is about 100-200 drops per minute.

Technical Field

The invention belongs to the technical field of food processing, and particularly relates to an edible casing and a preparation method thereof.

Background

Edible artificial casings are generally prepared from collagen extracted from animal skin, bones, intestines and tendons, or vegetable proteins such as soybean, peanut and corn. When the sausage casing is eaten, the sausage casing can be eaten together with the sausage casing, can be digested and absorbed by gastric enzymes of a human body, and is beneficial and harmless to the human body. The edible casing is a product which integrates the subjects of physics, chemistry, biology, machinery and the like, has higher technical content and is more complex to produce.

Most of the raw materials of the artificial edible casings on the market at present are collagen, but the collagen has the defects of high price, large pollution generated in the extraction process, sensitization possibility and limitation on the application of halal food. The rising costs, increased consumer safety awareness, and increased demand for halal food products have driven casing manufacturers to find alternatives to collagen casings, such as vegetable casings, and the like. In the prior research at home and abroad, whey protein, chitosan, pectin/gelatin/sodium alginate and other raw materials are used for preparing novel casings, but the raw and auxiliary materials adopted by the casings are not strictly derived from plants and still have potential sensitization.

The research of using cereal protein to make edible casings is relatively deficient. Collagen is a biological high molecular substance with a unique molecular structure, is fibrous protein consisting of linear polypeptides and has a compact supercoiled structure, and cereal protein is an oligomer consisting of different polypeptides and is globular protein. The secondary structure of collagen is the collagen helix, while the secondary structure of vegetable proteins is 5-15% alpha-helix. Because, in the process of preparing sausage casing, collagen is more favorable for forming compact structure to achieve the mechanical strength, water solubility and permeability required by sausage, and cereal protein is influenced by the structure of the cereal protein, although the edible film can be prepared, the cereal protein has lower mechanical strength, is easy to break, is easy to crisp and is easy to dissolve in water, and cannot be used as the sausage casing for sausage. However, the cereal protein can be further improved on the basis of being used as an edible film, so that the cereal protein has improved properties in all aspects and is suitable for being used as a sausage casing.

At present, edible casings in China mostly use collagen as a raw material, and have the problems of complex production process, immature technology, low strength and the like, so that a novel edible casing needs to be explored urgently.

Disclosure of Invention

The purpose of the invention is: an edible casing is provided. The edible casing has low sensitization, high mechanical strength and compact structure; the invention also provides a preparation method thereof.

The edible casing glue solution comprises the following raw materials in percentage by mass: pea protein 7.5-8.0%, sodium alginate 1.0-1.5%, glycerin 0.5-1.0%, caprylic/capric glyceride 1.5-2.0%, transglutaminase 0.25-0.45%, microcrystalline cellulose 0.5-0.8%, lignin 1.5-2.0%, sodium dodecyl sulfate 0.1-0.3% and balance water; the cross-linking agent comprises calcium lactate, calcium gluconate and glutaraldehyde.

Preferably, the edible casing glue solution of the invention comprises the following raw materials in percentage by mass: pea protein 8.0%, sodium alginate 1.0%, glycerol 0.8%, caprylic capric acid glyceride 1.7%, transglutaminase (TG enzyme) 0.40%, microcrystalline cellulose 0.5%, lignin 1.5%, sodium dodecyl sulfate 0.3% and balance water.

According to the edible casing, pea protein and sodium alginate are used as main film forming substances, the mass ratio of the pea protein in a glue solution is controlled to be 7.5-8.0%, and the mass ratio of the sodium alginate in the glue solution is controlled to be 1.0-1.5%, when the addition amount of the pea protein is reduced, the gel property cannot be fully exerted, but when all the pea proteins are selected, the stability of a gel system is poor, so that the strength and elasticity of the prepared edible casing are reduced. The preparation method is characterized in that the pea proteins are modified by using transglutaminase (TG enzyme), the TG enzyme induces the pea proteins to generate new cross-linking, and the network structure of the edible casing is enhanced, the network structure is mainly maintained by depending on hydrogen bonds and hydrophobic action, so that the mechanical strength for preparing the casing is increased, but the defect also exists, the moisture content of the film can be reduced, and therefore, sodium dodecyl sulfate is added, and the oil-soluble solution is dip-coated in the shrinking process. Compared with the prior art that glycerin is used as a plasticizer, the compound of glycerin and caprylic capric glyceride is used as the plasticizer, the compound plasticizer is more convenient to feed, does not stick hands and equipment, and does not stick to a dragging wheel in the process of casing blowing, so that the casing is not easy to crack. The glycerol has influence on the performance of the TG enzyme modified edible casing, the flexibility of the edible casing can be increased, the interface energy of a glue solution system is reduced due to the addition of the caprylic-capric glyceride, the tissue structure of the prepared edible casing is improved, and the water evaporation of the casing can be inhibited; in addition, in the plasticizing system, the sodium dodecyl sulfate can play a synergistic role, and the elongation of the edible casing can be effectively increased. The microcrystalline cellulose and the edible cellulose lignin are compounded for use, so that the toughness of the prepared edible casing is improved, and the edible casing is prevented from cracking in the preparation process.

The preparation method of the edible casing comprises the following steps:

(1) uniformly mixing glycerol, caprylic capric acid glyceride, transglutaminase and water to obtain a mixed solution, adding a mixture of pea protein, sodium alginate, microcrystalline cellulose, lignocellulose and sodium dodecyl sulfate into the mixed solution to form a glue solution, and chopping and mixing to form gel;

(2) extruding and molding the gel prepared in the step (1), spraying the outer wall of the casing with a mixed solution of calcium lactate and calcium gluconate, and spraying the inner wall of the casing with glutaraldehyde; after spraying, washing and drying the casing;

(3) shrinking the dried sausage casing, and dip-coating an oil-soluble solution on the outer wall of the sausage casing in the shrinking process;

(4) curing: firstly, aging at 45-50 ℃ for 0.5-1.0h, and then aging at 53-55 ℃ and relative humidity of 50-55% for 48-55h to prepare the edible casing.

Wherein:

the chopping and mixing temperature in the step (1) is less than or equal to 15 ℃, and the chopping and mixing time is 30-40 min; the chopping mixing temperature is controlled to be less than or equal to 15 ℃, so that the stability of protein is ensured, and the propagation of microorganisms is prevented.

Stirring and vacuum degassing are carried out after chopping in the step (1), the vacuum degree is 0.1MPa, and the degassing time is 5-7min, so that bubbles are removed, and the later-stage film forming is facilitated.

The extrusion molding speed in the step (2) is 20-50 m/min.

When the inner wall spraying in the step (2) is just sprayed out of the casing head, capillary spraying is adopted at the machine head, glutaraldehyde is sprayed all the time along with the spraying of the casing, and the concentration of the glutaraldehyde is 0.02-0.05%. And (3) cooling the glutaraldehyde solution by a pipeline, wherein the temperature of the cooling water is controlled to be 5-10 ℃.

When the outer wall spraying in the step (2) is just spraying out of the casing head, the casing head adopts radial spraying, mixed liquid of calcium lactate and calcium gluconate is sprayed all the time along with the spraying out of the casing, and the mass concentration of the mixed liquid of calcium salt is 25-30%, wherein: the mass ratio of calcium lactate to calcium gluconate is 2-3: 1.

The spraying amount of the mixed solution of calcium lactate and calcium gluconate in the step (2) is enough to ensure that the sausage casing can be completely wrapped and can be replenished for recycling.

The mass concentration of the glutaraldehyde in the step (2) is 0.02-0.05%.

The drying temperature of the sausage casing in the step (2) is 50-55 ℃, and the drying time is 20-25 min.

The oil-soluble solution in the step (3) is a mixed solution of white oil and glycerol monooleate, wherein the mass ratio of the white oil to the glycerol monooleate is 1: 0.1-0.15.

During the shrinkage in the step (3), the sausage casing is dipped in the oil-soluble solution through the sponge with oil, and the amount of the oil-soluble solution on the sponge is about 100-200 drops per minute.

According to the preparation method of the edible casing, the inner wall of the casing is crosslinked by glutaraldehyde, aldehyde groups in the glutaraldehyde and amino groups of protein are subjected to crosslinking reaction, and the performance of a protein-based membrane is improved; the outer wall is modified by a compound of calcium lactate and calcium gluconate, and the addition of organic calcium can greatly slow down the crosslinking speed with sodium alginate, so that the crosslinking is more sufficient, and the strength of the prepared edible casing is enhanced. The oil-soluble solution is dip-coated in the casing shrinkage process, the Glycerol Monooleate (GMO) is added as a nonionic surfactant, the stability is high, the nutritional value is high, the migration of oily components can be inhibited, the surface viscosity is reduced, the toughness of the casing is increased, the mixed liquid of the white oil and the glycerol monooleate has the function of an emulsifier, and the prepared edible casing has good barrier property and mechanical property due to the addition of the emulsifier. After the shrinkage is finished, the casing is aged for a period of time at 45-50 ℃, and then aged at a certain humidity, so that the crosslinking reaction is further promoted, the crosslinking degree is increased, and the mechanical strength of the casing is improved.

Compared with the prior art, the invention has the following beneficial effects:

(1) the edible casing provided by the invention selects pea protein and sodium alginate as main film forming substances, has wide raw material sources, low price and degradability and renewability, and is modified by adding the plasticizer, the reinforcing agent, sodium dodecyl sulfate, TG enzyme and the like, so that the prepared edible casing has low allergenicity, high mechanical strength, compact structure, good skin and stuffing combination and stable quality.

(2) The preparation method of the edible casing has simple process and easily controlled parameters, is suitable for industrialized popularization and production, adopts the cross-linking of the inner wall and the outer wall, dip-coats the oil-soluble solution in the shrinking process, and leads the prepared edible casing to have excellent performance through the curing process.

Detailed Description

The present invention is further described below with reference to examples.

Example 1

The edible casing according to the embodiment 1, the casing glue solution comprises the following raw materials by mass percent: pea protein 8.0%, sodium alginate 1.0%, glycerol 0.8%, caprylic capric acid glyceride 1.7%, transglutaminase (TG enzyme) 0.40%, microcrystalline cellulose 0.5%, lignin 1.5%, sodium dodecyl sulfate 0.3% and balance water; the cross-linking agent comprises calcium lactate, calcium gluconate and glutaraldehyde.

In the edible casing described in this embodiment 1, pea protein and sodium alginate are used as main film forming substances, the mass ratio of the pea protein in the gum solution is controlled to be 8.0%, and the mass ratio of the sodium alginate in the gum solution is controlled to be 1.0%, when the addition amount of the pea protein is reduced, the gel property cannot be fully exerted, but when all the pea proteins are selected, the stability of the gel system is poor, so that the strength and elasticity of the prepared edible casing are reduced. The preparation method is characterized in that the pea proteins are modified by using transglutaminase (TG enzyme), the TG enzyme induces the pea proteins to generate new cross-linking, and the network structure of the edible casing is enhanced, the network structure is mainly maintained by depending on hydrogen bonds and hydrophobic action, so that the mechanical strength for preparing the casing is increased, but the defect also exists, the moisture content of the film can be reduced, and therefore, sodium dodecyl sulfate is added, and the oil-soluble solution is dip-coated in the shrinking process. Compared with the prior art that glycerin is used as a plasticizer, the compound of glycerin and caprylic capric glyceride is used as the plasticizer, the compound plasticizer is more convenient to feed, does not stick hands and equipment, and does not stick to a dragging wheel in the process of casing blowing, so that the casing is not easy to crack. The glycerol has influence on the performance of the TG enzyme modified edible casing, the flexibility of the edible casing can be increased, the interface energy of a glue solution system is reduced due to the addition of the caprylic-capric glyceride, the tissue structure of the prepared edible casing is improved, and the water evaporation of the casing can be inhibited; in addition, in the plasticizing system, the sodium dodecyl sulfate can play a synergistic role, and the elongation of the edible casing can be effectively increased. The microcrystalline cellulose and the edible cellulose lignin are compounded for use, so that the toughness of the prepared edible casing is improved, and the edible casing is prevented from cracking in the preparation process.

The preparation method of the edible casing according to the embodiment 1 comprises the following steps:

(1) uniformly mixing glycerol, caprylic capric acid glyceride, transglutaminase and water to obtain a mixed solution, adding a mixture of pea protein, sodium alginate, microcrystalline cellulose, lignocellulose and sodium dodecyl sulfate into the mixed solution to form a glue solution, and chopping and mixing to form gel;

(2) extruding and molding the gel prepared in the step (1), spraying the outer wall of the casing with a mixed solution of calcium lactate and calcium gluconate, and spraying the inner wall of the casing with glutaraldehyde; after spraying, washing and drying the casing;

(3) shrinking the dried sausage casing, and dip-coating an oil-soluble solution on the outer wall of the sausage casing in the shrinking process;

(4) curing: firstly, aging at 50 ℃ for 0.7h, and then aging at 55 ℃ and a relative humidity of 50% for 50h to prepare the edible casing.

Wherein:

the chopping and mixing temperature in the step (1) is 10 ℃, and the chopping and mixing time is 35 min; the chopping mixing temperature is controlled to be 10 ℃, so that the stability of protein is ensured, and the propagation of microorganisms is prevented.

Stirring and vacuum degassing are carried out after chopping in the step (1), the vacuum degree is 0.1MPa, and the degassing time is 7min, so that bubbles are removed, and the later-stage film forming is facilitated.

The extrusion molding rate in the step (2) was 38 m/min.

When the inner wall spraying in the step (2) is just sprayed out of the casing head, capillary spraying is adopted at the machine head, glutaraldehyde is sprayed all the time along with the spraying of the casing, and the concentration of the glutaraldehyde is 0.04%. And (3) cooling the glutaraldehyde solution by a pipeline, wherein the temperature of the cooling water is controlled at 10 ℃.

The outer wall spraying in the step (2) is that when the casing is just sprayed out of the machine head, the machine head adopts radial spraying, mixed liquid of calcium lactate and calcium gluconate is sprayed all the time along with the spraying of the casing, the mass concentration of the mixed liquid of calcium salt is 25%, wherein: the mass ratio of calcium lactate to calcium gluconate is 2.5: 1.

The spraying amount of the mixed solution of calcium lactate and calcium gluconate in the step (2) is enough to ensure that the sausage casing can be completely wrapped and can be replenished for recycling.

The mass concentration of the glutaraldehyde in the step (2) is 0.04%.

The drying temperature of the sausage casing in the step (2) is 50 ℃, and the drying time is 25 min.

The oil-soluble solution in the step (3) is a mixed solution of white oil and glycerol monooleate, wherein the mass ratio of the white oil to the glycerol monooleate is 1: 0.15.

During the shrinkage in the step (3), the sausage casing is dipped into the oil-soluble solution through the sponge with oil, and the amount of the oil-soluble solution on the sponge is about 140 drops per minute.

In the preparation method of the edible casing described in this embodiment 1, glutaraldehyde is selected for the inner wall of the casing for crosslinking, and aldehyde groups in the glutaraldehyde and amino groups of protein perform a crosslinking reaction, so as to improve the performance of the protein-based membrane; the outer wall is modified by a compound of calcium lactate and calcium gluconate, and the addition of organic calcium can greatly slow down the crosslinking speed with sodium alginate, so that the crosslinking is more sufficient, and the strength of the prepared edible casing is enhanced. In the casing shrinkage process, oil-soluble solution is dip-coated, Glycerol Monooleate (GMO) is added as a nonionic surfactant, the stability is high, the nutritional value is high, the migration of oily components can be inhibited, the surface viscosity is reduced, the toughness of the casing is increased, the oil-soluble solution formed by compounding white oil and glycerol monooleate oil has the function of an emulsifier, and the prepared edible casing has good barrier property and mechanical property due to the addition of the emulsifier. After the shrinkage is finished, the casing is aged at 50 ℃ for a period of time, and then is aged at a certain humidity, so that the crosslinking reaction is further promoted, the crosslinking degree is increased, and the mechanical strength of the casing is improved.

Example 2

The edible casing according to the embodiment 2, the casing glue solution comprises the following raw materials by mass percent: 7.5% of pea protein, 1.3% of sodium alginate, 0.5% of glycerol, 1.8% of caprylic/capric glyceride, 0.25% of transglutaminase, 0.6% of microcrystalline cellulose, 1.7% of lignin, 0.2% of sodium dodecyl sulfate and the balance of water; the cross-linking agent comprises calcium lactate, calcium gluconate and glutaraldehyde.

The preparation method of the edible casing according to embodiment 2 comprises the following steps:

(1) uniformly mixing glycerol, caprylic capric acid glyceride, transglutaminase and water to obtain a mixed solution, adding a mixture of pea protein, sodium alginate, microcrystalline cellulose, lignocellulose and sodium dodecyl sulfate into the mixed solution to form a glue solution, and chopping and mixing to form gel;

(2) extruding and molding the gel prepared in the step (1), spraying the outer wall of the casing with a mixed solution of calcium lactate and calcium gluconate, and spraying the inner wall of the casing with glutaraldehyde; after spraying, washing and drying the casing;

(3) shrinking the dried sausage casing, and dip-coating an oil-soluble solution on the outer wall of the sausage casing in the shrinking process;

(4) curing: firstly aging at 45 deg.C for 1.0h, and then aging at 54 deg.C and 52% relative humidity for 52h to obtain edible casing.

Wherein:

the chopping and mixing temperature in the step (1) is 10 ℃, and the chopping and mixing time is 30 min; the chopping mixing temperature is controlled to be 10 ℃, so that the stability of protein is ensured, and the propagation of microorganisms is prevented.

Stirring and vacuum degassing are carried out after chopping in the step (1), the vacuum degree is 0.1MPa, and the degassing time is 5min, so that bubbles are removed, and the later-stage film forming is facilitated.

The extrusion molding rate in the step (2) was 50 m/min.

When the inner wall spraying in the step (2) is just sprayed out of the casing head, capillary spraying is adopted at the machine head, glutaraldehyde is sprayed all the time along with the spraying of the casing, and the concentration of the glutaraldehyde is 0.02%. And (3) cooling the glutaraldehyde solution by a pipeline, wherein the temperature of the cooling water is controlled at 10 ℃.

When the outer wall spraying in the step (2) is just spraying out of the casing head, the casing head is sprayed in a radial shape, mixed liquid of calcium lactate and calcium gluconate is sprayed all the time along with the spraying out of the casing, and the mass concentration of the mixed liquid of calcium salt is 26%, wherein: the mass ratio of calcium lactate to calcium gluconate is 2: 1.

The spraying amount of the mixed solution of calcium lactate and calcium gluconate in the step (2) is enough to ensure that the sausage casing can be completely wrapped and can be replenished for recycling.

The mass concentration of the glutaraldehyde in the step (2) is 0.02%.

The drying temperature of the sausage casing in the step (2) is 52 ℃, and the drying time is 23 min.

The oil-soluble solution in the step (3) is a mixed solution of white oil and glycerol monooleate, wherein the mass ratio of the white oil to the glycerol monooleate is 1: 0.13.

During the shrinkage in the step (3), the sausage casing is dipped into the oil-soluble solution through the sponge with oil, and the amount of the oil-soluble solution on the sponge is about 160 drops per minute.

Example 3

The edible casing according to embodiment 3, the casing glue solution comprises the following raw materials in percentage by mass: 7.7% of pea protein, 1.5% of sodium alginate, 1.0% of glycerol, 1.5% of caprylic/capric glyceride, 0.32% of transglutaminase, 0.7% of microcrystalline cellulose, 1.6% of lignin, 0.3% of sodium dodecyl sulfate and the balance of water; the cross-linking agent comprises calcium lactate, calcium gluconate and glutaraldehyde.

The preparation method of the edible casing according to embodiment 3 comprises the following steps:

(1) uniformly mixing glycerol, caprylic capric acid glyceride, transglutaminase and water to obtain a mixed solution, adding a mixture of pea protein, sodium alginate, microcrystalline cellulose, lignocellulose and sodium dodecyl sulfate into the mixed solution to form a glue solution, and chopping and mixing to form gel;

(2) extruding and molding the gel prepared in the step (1), spraying the outer wall of the casing with a mixed solution of calcium lactate and calcium gluconate, and spraying the inner wall of the casing with glutaraldehyde; after spraying, washing and drying the casing;

(3) shrinking the dried sausage casing, and dip-coating an oil-soluble solution on the outer wall of the sausage casing in the shrinking process;

(4) curing: firstly, aging at 48 ℃ for 0.8h, and then aging at 54 ℃ for 53h under the condition that the relative humidity is 53 percent to prepare the edible casing.

Wherein:

the chopping and mixing temperature in the step (1) is 10 ℃, and the chopping and mixing time is 38 min; the chopping mixing temperature is controlled to be 10 ℃, so that the stability of protein is ensured, and the propagation of microorganisms is prevented.

Stirring and vacuum degassing are carried out after chopping in the step (1), the vacuum degree is 0.1MPa, and the degassing time is 6min, so that bubbles are removed, and the later-stage film forming is facilitated.

The extrusion molding rate in the step (2) was 35 m/min.

When the inner wall spraying in the step (2) is just sprayed out of the casing head, capillary spraying is adopted at the machine head, glutaraldehyde is sprayed all the time along with the spraying of the casing, and the concentration of the glutaraldehyde is 0.03%. And (3) cooling the glutaraldehyde solution by a pipeline, wherein the temperature of the cooling water is controlled at 10 ℃.

When the outer wall spraying in the step (2) is just spraying out of the casing head, the casing head is sprayed in a radial shape, mixed liquid of calcium lactate and calcium gluconate is sprayed all the time along with the spraying out of the casing, the mass concentration of the mixed liquid of calcium salt is 28%, wherein: the mass ratio of calcium lactate to calcium gluconate is 3: 1.

The spraying amount of the mixed solution of calcium lactate and calcium gluconate in the step (2) is enough to ensure that the sausage casing can be completely wrapped and can be replenished for recycling.

The mass concentration of the glutaraldehyde in the step (2) is 0.03%.

The drying temperature of the sausage casing in the step (2) is 55 ℃, and the drying time is 20 min.

The oil-soluble solution in the step (3) is a mixed solution of white oil and glycerol monooleate, wherein the mass ratio of the white oil to the glycerol monooleate is 1: 0.12.

During the shrinkage in the step (3), the sausage casing is dipped into oil-soluble solution through the sponge with oil, and the amount of the oil-soluble solution on the sponge is about 170 drops per minute.

Example 4

The edible casing according to embodiment 4, the casing glue solution comprises the following raw materials in percentage by mass: pea protein 8.0%, sodium alginate 1.5%, glycerol 0.8%, caprylic capric acid glyceride 2.0%, transglutaminase 0.43%, microcrystalline cellulose 0.8%, lignin 1.6%, sodium dodecyl sulfate 0.3% and the balance of water; the cross-linking agent comprises calcium lactate, calcium gluconate and glutaraldehyde.

The preparation method of the edible casing according to embodiment 4 comprises the following steps:

(1) uniformly mixing glycerol, caprylic capric acid glyceride, transglutaminase and water to obtain a mixed solution, adding a mixture of pea protein, sodium alginate, microcrystalline cellulose, lignocellulose and sodium dodecyl sulfate into the mixed solution to form a glue solution, and chopping and mixing to form gel;

(2) extruding and molding the gel prepared in the step (1), spraying the outer wall of the casing with a mixed solution of calcium lactate and calcium gluconate, and spraying the inner wall of the casing with glutaraldehyde; after spraying, washing and drying the casing;

(3) shrinking the dried sausage casing, and dip-coating an oil-soluble solution on the outer wall of the sausage casing in the shrinking process;

(4) curing: firstly aging at 50 deg.C for 0.6h, and then aging at 53 deg.C and relative humidity of 54% for 55h to obtain edible casing.

Wherein:

the chopping and mixing temperature in the step (1) is 10 ℃, and the chopping and mixing time is 38 min; the chopping mixing temperature is controlled to be 10 ℃, so that the stability of protein is ensured, and the propagation of microorganisms is prevented.

Stirring and vacuum degassing are carried out after chopping in the step (1), the vacuum degree is 0.1MPa, and the degassing time is 7min, so that bubbles are removed, and the later-stage film forming is facilitated.

The extrusion molding rate in the step (2) is 40 m/min.

When the inner wall spraying in the step (2) is just sprayed out of the casing head, capillary spraying is adopted at the machine head, glutaraldehyde is sprayed all the time along with the spraying of the casing, and the concentration of the glutaraldehyde is 0.05%. And (3) cooling the glutaraldehyde solution by a pipeline, wherein the temperature of the cooling water is controlled at 10 ℃.

When the outer wall spraying in the step (2) is just spraying out of the casing head, the casing head is sprayed in a radial shape, mixed liquid of calcium lactate and calcium gluconate is sprayed all the time along with the spraying out of the casing, the mass concentration of the mixed liquid of calcium salt is 28%, wherein: the mass ratio of calcium lactate to calcium gluconate is 2: 1.

The spraying amount of the mixed solution of calcium lactate and calcium gluconate in the step (2) is enough to ensure that the sausage casing can be completely wrapped and can be replenished for recycling.

The mass concentration of the glutaraldehyde in the step (2) is 0.05%.

The drying temperature of the sausage casing in the step (2) is 55 ℃, and the drying time is 23 min.

The oil-soluble solution in the step (3) is a mixed solution of white oil and glycerol monooleate, wherein the mass ratio of the white oil to the glycerol monooleate is 1: 0.10.

During the shrinkage in the step (3), the sausage casing is dipped into the oil-soluble solution through the sponge with oil, and the amount of the oil-soluble solution on the sponge is about 200 drops per minute.

Comparative example 1

The edible casing of comparative example 1 was prepared in the same manner as in example 1, except that the casing glue solution was prepared from the following raw materials in percentage by mass: 9.0% of pea protein, 0.8% of glycerol, 1.7% of caprylic/capric glyceride, 0.40% of transglutaminase (TG enzyme), 0.5% of microcrystalline cellulose, 1.5% of lignin, 0.3% of sodium dodecyl sulfate and the balance of water; the cross-linking agent is glutaraldehyde. In the preparation of the casing, the casing is crosslinked by spraying it with glutaraldehyde alone.

Comparative example 2

The edible casing of comparative example 2 was prepared in the same manner as in example 1, except that the casing glue solution was prepared from the following raw materials in mass percent: 9.0% of sodium alginate, 0.8% of glycerol, 1.7% of caprylic/capric glyceride, 0.5% of microcrystalline cellulose, 1.5% of lignin, 0.3% of sodium dodecyl sulfate and the balance of water; the cross-linking agent comprises calcium lactate and calcium gluconate. When preparing the sausage casing, the sausage casing is sprayed and crosslinked only by adopting the mixed solution of calcium lactate and calcium gluconate.

Comparative example 3

The edible casing of comparative example 3 was prepared in the same manner as in example 1, except that the casing glue was prepared from the following raw materials in mass percent: pea protein 8.0%, sodium alginate 1.0%, glycerol 0.8%, transglutaminase (TG enzyme) 0.40%, microcrystalline cellulose 0.5%, lignin 1.5% and balance water; the cross-linking agent comprises calcium lactate, calcium gluconate and glutaraldehyde.

Comparative example 4

The edible casing glue solution of the comparative example 4 has the same raw material and proportion as those of the edible casing glue solution of the example 1, and the only difference is that the preparation method is different, the oil-soluble solution of the invention described in the example 1 is not dipped on the outer wall of the casing in the shrinking process of the step (3), and the curing treatment is not performed after the shrinking process is finished.

The edible casings prepared in examples 1-4 and comparative examples 1-4 were subjected to performance tests, and the results are shown in table 1 below:

TABLE 1 edible casing Performance test results of examples 1-4 and comparative examples 1-4

The casing shrinkage process is not dipped with oil-soluble solution, so that the casing is dried and the sausage is easy to burst in the filling and cooking processes; in addition, the casing is put into a packaging bag for vacuum packaging after shrinkage, and then is subjected to curing treatment, so that the strength of the casing can be improved, and the mechanical strength of the prepared casing is reduced if the casing is not subjected to curing treatment.

Remarking: applying the test conditions: the filling speed of the stuffing is set to be 450 knots/minute, the stuffing enters a smoking furnace after filling, the smoking furnace adopts the process of drying at 60 ℃ for 20 minutes, the first step is steaming at 70 ℃ for 20 minutes, and the second step is steaming at 80 ℃ for 25 minutes; the next day after freezing overnight, the experiment of table baking, water boiling and frying is carried out.