Gel casing and system and method for its production

Abstract

The present invention relates to a semi-finished gel and a process for producing such semi-finished gel, suitable for use in the preparation of food gel casings, derived from a first natural tissue and a second natural tissue. The present invention further relates to a method for producing a homogeneous collagen-elastin gel, comprising a de-entanglement process in an extrusion system having a de-entanglement device including an interlocking member. The extrusion system further has a food dough extrusion passage and two cooperating jackets arranged coaxially with the food dough extrusion passage, at least one of which is rotatable around a co-extrusion axis, the jackets define an annular band between them having an annular band inlet for introducing the gel, the rotation of at least one of the jackets causes the gel to be oriented, thereby converting the introduced gel into an oriented gel, the annular band has opposing annular band outlets for discharging the oriented gel; the discharged oriented gel is deposited on the food dough coming out of the food dough outlet to form a food having a gel casing.

Description

Technical Field

[0001] The present invention relates to the preparation of a semi-finished gel suitable for use as a food gel casing derived from materials rich in casein and / or elastin, the semi-finished product thus obtained, an extrusion system and method for making a food gel casing from the semi-finished gel, and the food thus obtained.

Background Art

[0002] A typical method of producing sausage involves grinding the protein and mixing it with salt, curing agents (if applicable), spices, flavors, sweeteners, extenders (such as milk solids, starch, grains, etc.) and water before stuffing the ground protein into a tubular gel casing.

[0003] Natural casings can be, for example, the intestines of animals derived from beef cattle, pigs or sheep. However, natural casings have a non-uniform thickness, are not structurally consistent, and may have religious restrictions. Furthermore, natural casings require careful cleaning and preparation, are in short supply, and are relatively expensive.

[0004] Artificial gel casings are generally made of collagen, cellulose and / or plastic. Artificial gel casings derived from animal collagen are generally edible. Collagen gel casings are mainly produced from the collagen in the skin, bones and tendons of beef cattle or pigs. It can also be derived from poultry and fish.

[0005] From US Patent Application Publication No. 2008 / 0317915, an edible gel casing for food products having collagen and polysaccharides, and a method for manufacturing the gel casing are known. Collagen is a fibrous protein preferred for use in gel casings. This document also proposes using another fibrous protein such as keratin or elastin instead of some or all of the collagen.

[0006] The gel for the gel casing is processed extensively. Preferably, collagen is provided as a collagen gel that is co-extruded with food dough. In this context, extrusion is the process of shaping a product by forcing a material to pass through a die. The food dough is extruded through a food dough extrusion passage. The gel is extruded through an annular band provided coaxially with the food dough extrusion passage. The extruded gel deposits on the food dough coming out of the food dough extrusion passage, forming a food product with a gel casing.

[0007] In a continuous co-extrusion process, a single sausage gel casing of variable length is produced, which is then usually cut to a predetermined length while the co-extrusion process is ongoing. Subsequent processing may include, for example, dehydration with a setting solution using a bath, and modification of the product's shape by, for example, winding, smoking, and drying. Typically, the product will require drying or other steps to bring the collagen from solidified but still moist conditions to a stable and handleable state. The gel casing may be tanned with agents such as, for example, formaldehyde, smoke extract, alum, and dialdehyde alaginate.

[0008] U.S. Patent No. 3,622,353 discloses the preparation of collagen-coated sausages. During the production process, collagen is extruded onto the food product in a tubular form. By using a reverse-rotating die, frictional force is applied to the extruded collagen fibers, which is thought to result in the orientation of the collagen fibers in a manner that satisfies the strength of the collagen coating or gel casing in all directions. To achieve the required orientation of the collagen fibers, the document specifies that when using a double (reverse) rotating jacket, the extruder jacket should be rotated at 60 to 120 r.pm (revolutions per minute).

[0009] U.S. Patent Application Publication No. 2016 / 0227793 describes a method for extruding a gel casing of collagen or a collagen-containing mixture, in which two counter-rotating jackets each rotate at a rotational speed of 150–300 r.pm. Due to the two rotatable and cooperating jackets, the collagen (or collagen-containing mixture) is handled in such a way that the orientation of fibrous collagen is affected in a controlled manner. The orientation of fibrous collagen (at least the major component of the collagen-containing mixture) significantly affects the tissue structure of the extruded collagen gel casing (e.g., the morphology of the extracellular matrix (ECM)), which in turn affects various mechanical properties (such as strength and elasticity).

[0010] The amount of gel used in the co-extrusion process is also called the pick-up. The extrusion process may use up to 10 wt% gel relative to the weight of the food dough being extruded to obtain acceptable properties. More gel means more water to evaporate during further processing, resulting in increased time and cost.

[0011] The object of the present invention is to provide a collagen-elastin gel casing having improved properties such as strength, appearance, regeneration properties (reheating), and "snap" and / or "bite" characteristics of natural gel-casing foods.

[0012] This objective is achieved by providing an improved semi-finished gel suitable for use in the preparation of food-grade gel casings.

[0013] Collagen is a major structural protein in the extracellular matrix found in various connective tissues of the body. As the main component of connective tissue, it is often the most abundant protein in mammals, accounting for 25-35% of the total protein content. Collagen consists of amino acids that bind together to form a triple helix of elongated fibrils known as the collagen helix. It is found mostly in connective tissues such as cartilage, bone, tendons, ligaments, and skin, as well as in the cornea, blood vessels, digestive tract, and intervertebral discs. Elastin is an important component of the extracellular matrix in jawed vertebrates. It is highly elastic and present in connective tissue, allowing many tissues in the body to regain their shape after stretching or contraction. Elastin helps skin return to its original position when poked or pinched. Elastin plays an important role in aiding blood flow and is particularly abundant in large elastic blood vessels such as the aorta. Elastin is also found in the lungs, elastic ligaments, elastic cartilage, skin, and bladder.

[0014] Typically, natural tissues such as skin, the digestive tract, casings, bladder, stomach, arteries and veins, and other organs contain collagen and elastin, albeit in different proportions. For example, the digestive tract usually contains more collagen than elastin, while the bladder usually contains more elastin than collagen. The ratio of collagen to elastin may vary from animal species to animal species. [Overview of the project]

[0015] The inventors have found that a gel containing a combination of elastin and collagen can provide improved properties in food casing gels, particularly when subjected to a combination of chemical unfolding and physical treatment (disentanglement). This gel can be made from a first natural tissue and a second natural tissue, such as beef split and bladder. The first natural tissue is relatively rich in collagen compared to the second natural tissue. The second natural tissue is relatively rich in elastin compared to the first natural tissue.

[0016] Therefore, in a first aspect, the present invention relates to a method for producing a semi-finished gel suitable for use in the preparation of food gel casings, the method for providing a semi-finished gel having collagen and elastin: The process involves providing a first (collagen-rich) natural tissue, such as beef cattle split, and a second (elastin-rich) natural tissue, such as bladder. The ratio of the weight of collagen in the first (collagen-rich) natural tissue to the weight of collagen in the second (elastin-rich) natural tissue is greater than 1. The ratio of the weight of elastin in the second (elastin-rich) natural tissue to the amount of elastin in the first (collagen-rich) natural tissue is greater than 1. The first natural tissue and the second natural tissue are subjected to chemical treatment to provide the first natural tissue gel and the second natural tissue gel, respectively, and the first natural tissue gel and the second natural tissue gel are blended. or A combination of the first natural tissue and the second natural tissue is subjected to chemical treatment.

[0017] "First natural tissue" can be considered "collagen-rich," and as used herein, means a natural tissue containing collagen, such as the digestive tract, the ends of the digestive tract, beef cattle splits, tendons, natural casings, and other animal parts. To this end, "collagen-rich" means the significant presence of collagen such that the natural tissue can function as an effective collagen source for producing a collagen-rich gel. Collagen-rich tissues or products may contain some (trace) amounts of elastin, depending on the tissue. As used herein, "first natural tissue gel" means a gel obtained from the first natural tissue.

[0018] The “second natural tissue” can be considered “elastin-rich,” and as used herein, means natural tissues that contain elastin, such as skin, bladder, stomach, arteries, and veins. In this regard, elastin-rich means the significant presence of elastin such that the natural tissue can function as an effective source of elastin for producing elastin-rich gels. Elastin-rich tissues or products may contain a certain amount (trace amount) of collagen, depending on the tissue. As used herein, “secondary natural tissue gel” refers to a gel obtained from a secondary natural tissue.

[0019] The amount of collagen and / or elastin in natural tissue or gel can be determined by procedures known to those skilled in the art.

[0020] The first natural tissue differs from the second natural tissue in that it contains a higher amount of collagen (in wt%) than the second natural tissue. Therefore, the ratio of the amount of collagen in the first natural tissue to that in the second natural tissue is greater than 1.

[0021] The second natural tissue differs from the first natural tissue in that it contains a higher amount of elastin (in wt%) than the first natural tissue. Therefore, the ratio of the amount of elastin in the first natural tissue to that in the second natural tissue is greater than 1.

[0022] In another embodiment, the present invention also relates to a method for producing a semi-finished gel suitable for use in the preparation of food gel casings, the method comprising: (A)(i) providing a collagen-rich gel by subjecting a collagen-rich feed, such as beef split, to a chemical treatment; (ii) providing an elastin-rich gel by subjecting an elastin-rich feed, such as bladder, to a chemical treatment; and (iii) blending the collagen-rich gel and the elastin-rich gel; or (B) providing a mixture of the collagen-rich feed and the elastin-rich feed, and subjecting the mixture of the collagen-rich feed and the elastin-rich feed to a chemical treatment. As used herein, “collagen-rich feed” means a natural tissue containing collagen, such as the digestive tract, the end of the digestive tract, natural casing, and other parts of animals. In this regard, “collagen-rich” means a significant presence of collagen relative to elastin (i.e., containing more collagen than elastin by weight). Collagen-rich feed or product may contain a certain amount (trace amounts) of elastin depending on the tissue, but the fraction of elastin is smaller than the fraction of collagen. As used herein, “collagen-rich gel” means a gel obtained from a collagen-rich feed. As used herein, “elastin-rich feed” means a natural tissue containing elastin, such as skin, bladder, stomach, arteries, and veins. In this regard, elastin-rich means a significant presence of elastin relative to collagen (i.e., containing more elastin than collagen by weight). Elastin-rich feed or product may contain a certain amount (trace amounts) of collagen depending on the tissue, but the fraction of collagen is smaller than the fraction of elastin. As used herein, “elastin-rich gel” means a gel obtained from an elastin-rich feed.

[0023] As used herein, “supply” means raw materials containing elastin and / or collagen, such as skin, digestive tract, casing, bladder, stomach, arteries and veins, lungs, elastic ligaments, elastic cartilage, beef cattle splits, tendons, and other organs. These raw materials may have varying levels of collagen and / or elastin depending on the species or origin.

[0024] As used herein, “grinding product” refers to the feed that has been ground into even smaller fragments. As used herein, "caustic alkali solution treatment product" typically refers to a product subjected to treatment with a base (caustic alkali solution) at pH > 7. As used herein, “acid-treated product” typically refers to a product treated with an acid at a pH < 7. As used herein, “semi-finished gel” means a gel containing elastin and / or collagen, preferably both. The semi-finished gel may be a gel obtained from a second natural tissue gel and a first natural tissue gel by blending. The semi-finished gel may also be obtained by mixing raw materials containing elastin and / or collagen, which may be processed as described elsewhere herein, to form the semi-finished gel of the present invention. The semi-finished gel of the present invention may also be formed by combining intermediate products containing elastin and / or collagen, such as pulverized products, caustic alkali solution treated products, and / or acid treated products. As used herein, “homogeneous collagen-elastin gel” means a gel that has been subjected to a decomposition treatment to reduce fibrous clumps in the gel, typically a semi-finished gel, thereby converting the semi-finished gel into a homogeneous collagen-elastin gel. As used herein, "orientation gel" or "orientation collagen-elastin gel" means a gel subjected to rotation of at least one of two cooperating jackets that cause gel orientation, thereby converting the introduced gel into an orientation gel. As used herein, "gel casing" refers to a gel casing, gel casing film or gel film applied to a food (such as a sausage). Gel casings are typically subjected to drying, brining or smoking. As used herein, "natural casing" refers to a casing made from the natural digestive tract of animals such as sheep, pigs, and dairy cows.

[0025] The first natural tissue and the second natural tissue (either combined or separately) are subjected to chemical treatment to form a first natural tissue gel, a second natural tissue gel, or a gel containing both elastin and collagen derived from the first natural tissue and the second natural tissue, respectively. The second natural tissue gel and the first natural tissue gel can be blended to form a semi-finished gel. In certain embodiments, the second natural tissue and the first natural tissue are combined (as an intermediate product) before or during the chemical treatment to yield a semi-finished gel. As used herein, the fractional ratio in the semi-finished gel is calculated based on the wt% of the dry matter. In embodiments where the semi-finished gel is based on a blend of a second natural tissue gel and a first natural tissue gel: the relative amounts of elastin and collagen are calculated based on the relative amounts of the second natural tissue gel and the first natural tissue gel in the semi-finished gel. In embodiments where the semi-finished gel is based on a combination of a first natural tissue and a second natural tissue: the relative amounts of elastin and collagen are calculated based on the relative amounts of the second natural tissue and the first natural tissue in the combination. The relative amounts of elastin and collagen are calculated based on the relative amounts of the second natural tissue and the first natural tissue in the combination. In certain embodiments, the amount of the second natural tissue gel can exceed the amount of the first natural tissue gel in the semi-finished gel. In certain embodiments, the value of the ratio of elastin to collagen in the semi-finished gel can be greater than 1 (more elastin than collagen), preferably greater than 1.2, greater than 1.3, greater than 1.5, greater than 2. In certain embodiments, the ratio of the second natural tissue gel to the first natural tissue gel can be selected by weight from 100:0 (rich in elastin only) to 10:90, 80:20, 75:25, 50 / 50, 25 / 75, 90:10, and 0:100 (rich in collagen only). Preferably, the ratios are 10:90, 80:20, 75:25, 50 / 50, 25 / 75, and 90:10. In certain embodiments, the second natural tissue gel is present in the semi-finished gel in amounts exceeding 30 wt%, 40 wt%, 50 wt%, 60 wt%, 65 wt%, 70 wt%, and 75 wt%, and more preferably at least 80 wt%, 85 wt%, and 90 wt%, calculated based on the total amount of the semi-finished gel. In certain embodiments, the second natural tissue gel is present in the semi-finished gel in amounts of 30 wt% to 90 wt%, 40 wt% to 85 wt%, 50 wt% to 80 wt%, 60 wt% to 75 wt%, and 65 wt% to 70 wt%, calculated based on the total amount of the semi-finished gel.

[0026] In certain embodiments, the first natural tissue is present in the semi-finished gel at amounts of less than 50 wt%, 45 wt%, 40 wt%, 35 wt%, and 30 wt%, calculated based on the total amount of the mixture of the first and second natural tissues, and more preferably at amounts of less than 20 wt%, 15 wt%, and 10 wt%. In certain embodiments, the first natural tissue gel is present in the semi-finished gel in amounts of 10 wt% to 50 wt%, 15 wt% to 45 wt%, 20 wt% to 40 wt%, and 25 wt% to 35 wt%, calculated based on the total amount of the semi-finished gel.

[0027] The first natural tissue gel and / or the second natural tissue gel may be obtained by a chemical treatment, such as a chemical process that results in the unfolding of protein chains. The process sequence may have the following steps, which are: (a) a step of grinding the first natural tissue and / or the second natural tissue to provide a grinding product; (b) optionally, the step of subjecting the pulverized product of step (a) to a caustic alkali solution treatment to provide a caustic alkali solution treatment product, (c) optionally a step of mincing the product of step (a) or (b) to obtain a minced product; (d) optionally an acidification step of the product of step (a), (b), or (c) for obtaining an acid treatment product, (e) an aqueous dispersion step of the product of step (a), (b), (c), or (d), which is optionally combined with a milling process, (f) The step of obtaining a semi-finished gel suitable for use in the preparation of food gel casings.

[0028] Grinding the feed serves to enhance the surface. Preferably, the grinding step results in a ground product having an average dimension of 0.5–3 cm. Surface enlargement facilitates subsequent treatments aimed at denaturing / unfolding protein chains. Caustic alkali solution treatment is a treatment using a solution of a strong base such as sodium hydroxide or potassium hydroxide. Typically, an aqueous solution of a strong base with a molar concentration of 0.1–2 is used. Treatment with a strong base serves to denaturate / unfold proteins in the ground feed. Caustic alkali solution treatment may be carried out at a high temperature and / or for a period of 4–100 hours, preferably 10–75 hours, and more preferably 20–50 hours. Following treatment with a strong base, the surface of the caustic alkali solution treated product may be further enlarged by mincing it into a minced product which may preferably have an average dimension of 0.1–0.4 cm. The minced product can be subjected to acidification treatment in an acidic aqueous solution, more preferably an acid selected from the group consisting of lactic acid, acetic acid, hydrochloric acid, and mixtures thereof. Typically, an aqueous solution of acid with a molar concentration of 0.1 to 2 is used. The acidification treatment can be carried out at a high temperature and / or for a period of 4 to 100 hours, preferably 10 to 75 hours, more preferably 20 to 50 hours. Typically, acidification restores the isoelectric point of the relevant proteins. The acid-treated product may further be subjected to dispersion in an aqueous solution to produce a semi-finished gel, and optionally to milling and / or homogenization. Through this chemical unfolding process, the feed (first natural tissue, second natural tissue) or intermediate products (ground product, caustic alkali solution treatment product, minced product, acid treatment product) may be processed in separate flows, or the flows may be combined at any stage. Thus, embodiments in which the first natural tissue and the second natural tissue, or the intermediate products resulting therefrom, may be combined prior to one or more of the grinding step, caustic alkali solution treatment step, mincing step, acidification step, dispersion step, or milling step. In embodiments, one or more washing treatments may be performed independently between individual steps of the process sequence. There is a preferred embodiment in which the first natural tissue gel and the second natural tissue gel are formed in separate process sequences. This allows each process sequence to be optimized for a specific product, thereby improving the quality of the resulting first natural tissue gel and / or second natural tissue gel. The first natural tissue gel and the second natural tissue gel may be combined in an additional step in which the gels are blended or mixed. Combining the individual gels before obtaining the semi-finished gels allows for adjustment of the collagen / elastin ratio to accommodate desired variations in the final product, such as food casings. The formation of a semi-finished gel by combining the first natural tissue gel and the second natural tissue gel is preferably done by a mixing or blending step under "relatively low shear," i.e., in a state where the collagen or elastin protein chains are not sheared or broken. Suitable machinery for blending can be provided by industrial-scale low-shear mixers, such as those available from Glass Maschinenbau Germany. Suggestive examples are the VSM / F and VSM / C mixers.

[0029] The result of the method of the present invention is a semi-finished gel suitable for use in the preparation of food gel casings.

[0030] Accordingly, in one embodiment, the present invention relates to a semi-finished gel suitable for use as a food gel casing, which is preferably obtainable by the method of the present invention.

[0031] The formation of fibrous clumps in semi-finished collagen-elastin gels is a result of the gel's composition and typically occurs over time. This affects the storage life of the semi-finished collagen-elastin gel. The size of such fibrous clumps can vary generally between 0.1 and 5 mm, and particularly between 0.3 and 2 mm. Fibrous clumps are clusters of protein fibers that are too large and undesirable to be included in a gel deposited as a gel casing, resulting in a tangled or matted appearance. At the molecular level, such fibrous clumps resemble a plate of spaghetti or tangled hair (see Figure 5 for a schematic diagram). When fibrous clumps are present in the gel when deposited as a gel casing on food dough, undesirable pores and irregularities are likely to occur in the gel casing. This casing will have lower mechanical strength. Since the collagen clumps will be darker in color, uneven color formation in the fumigation solution may occur due to the fibrous clumps.

[0032] The inventors also solved this problem by subjecting the semi-finished gel to a de-corrosion treatment.

[0033] Accordingly, in a further embodiment, the present invention also relates to a method for making a gel casing for food, the method comprising the steps of providing a semi-finished gel and subjecting the semi-finished gel to a decomposition treatment to provide a homogeneous collagen-elastin gel.

[0034] By subjecting the semi-finished gel to a de-corrosion treatment, clumping and lumps are reduced, forming a homogeneous collagen-elastin gel. Between the cohesive jackets, the protein (collagen / elastin) chains are further oriented or straightened, forming an oriented collagen-elastin gel. The resulting product has excellent properties and is particularly advantageous when used as a gel casing for food applications.

[0035] In particular, it has been found that when the innovative gel casings described above are applied, the properties of the resulting products are even better compared to those obtained with known gel casings.

[0036] Since homogeneous collagen-elastin gels tend to tangle over time, it is preferable that the detangling process be performed immediately before orientation and immediately before the oriented collagen-elastin gel is introduced onto the food. It is preferable that there be a period of no more than 2 hours, and particularly less than 30 minutes, between the detangling process and the production of the food by encasing the food dough. In an extrusion system for continuous production of food having a collagen-elastin gel casing, the detangling occurs before the operation of the cooperating jacket.

[0037] This objective is further achieved by providing the extrusion system described in claim 16.

[0038] Advantageously, the innovative gel and extrusion system allows for the acquisition of desired product characteristics with relatively small amounts of gel casing. In some embodiments, the innovative extrusion process may use approximately 4–5 wt% of the innovative gel casing relative to the food dough being extruded (also known as the "pickup"). Less gel casing means less water is evaporated during the process, which can reduce time / energy and the amount of gel casing used.

[0039] The innovative gel casing has been found to produce an even wider range of products, including sausage reheating in hot water, roller grilling, or pan-frying, as well as barbecue cooking.

[0040] An innovative extrusion system for the continuous production of food products with collagen-elastin gel casings is: - It has a food dough extrusion passage that defines a co-extrusion axis, and this food dough extrusion passage has a food dough inlet and an opposing food dough outlet; - It has two cooperating jackets arranged coaxially with the food dough extrusion passage, at least one of which is rotatable around the co-extrusion axis, and these jackets define an annular band between them having an annular band inlet for introducing the gel, the rotation of at least one of the jackets causes the gel to be oriented, thereby converting the introduced gel into an oriented gel, and the annular band has opposing annular band outlets for discharging the oriented gel; the discharged oriented gel deposits on the food dough coming out of the food dough outlet to form a food having a gel casing; - The device has an adjacent series upstream detangulation device, which has: a detangulation device inlet for a semi-finished gel; interlock members, which define a labyrinth between them, and at least one of the interlock members is movable to perform mechanical processing on the semi-finished gel in the labyrinth to reduce fibrous clumps in the gel, thereby converting the semi-finished gel into a homogeneous collagen-elastin gel; and a detangulation device outlet for a homogeneous collagen-elastin gel, which is introduced between two cooperating jackets to be converted into an oriented collagen-elastin gel.

[0041] An innovative detangulation device is provided to reduce fibrous clumps in a gel before its extrusion, thereby forming a homogeneous collagen-elastin gel. A semi-finished gel with fibrous clumps flows through a labyrinth between two interlocking members. The detangulation device has at least one movable interlocking member that performs continuous mechanical treatment, particularly high shear treatment, on the semi-finished gel, thereby "loosening" the (long) collagen and elastin fibers and knots in the gel, reducing fibrous clumps in the gel, and producing a substantially homogeneous gel free of fibrous clumps. The mechanical treatment causes dispersion of fibrous clumps in the gel, resulting in a substantially homogeneous gel free of fibrous clumps. This results in better extrusion, better film-forming ability, and better gel casing properties (particularly its texture, e.g., a higher "bite" value).

[0042] In embodiments, the interlocking member of the detangulation device has rows of projections (24, 25, 26), such as toothed projections or sawtoothed edges. Embodiments in which the interlocking member has one or more rows of projections, for example, two or three, are conceivable. Such rows of tines or teeth for the interlock generate a detangulation labyrinth that improves the mechanical handling of the semi-finished gel.

[0043] In the embodiment, more than one interlocking member is movable. Advantageously, two interlocking members are relatively movable, improving the mechanical handling of the semi-finished gel.

[0044] In an embodiment, the detangulation device has an interlocking member positioned coaxially with the co-extrusion axis. The movable interlocking member or both interlocking members are rotatable around the co-extrusion axis. Advantageously, the detangulation device has two relatively movable interlocking members, for example, two counter-rotatable interlocking members.

[0045] If coaxially arranged interlock members are used, it is conceivable that the protrusions of the interlock members may be in series with the co-extrusion shaft, perpendicular to the co-extrusion shaft, or oriented in any other way relative to the co-extrusion shaft.

[0046] A cooperating jacket is provided adjacent to and downstream of the detangulation device, and the rotation of at least one jacket causes the orientation of fibers in the semi-finished gel, forming an oriented collagen-elastin gel. Collagen and elastin have fibrous properties, and due to the extrusion of collagen, the collagen fibers in the resulting extruded gel casing tend to be oriented, and in particular, aligned. The rotating jacket surface applies shear forces to the fibers in the gel, and the shearing of the fibers on the jacket surface manipulates their alignment. These shear forces are smaller than the forces generated by the interlocking members in the labyrinth: these forces are not sufficient to overcome the detangulation forces of the proteins and detangle the fibrous mass.

[0047] Two cooperating jackets are arranged coaxially with the food dough extrusion passage, and at least one of the jackets is rotatable around the co-extrusion axis. In embodiments, both jackets are rotatable, preferably in opposite directions.

[0048] In the embodiment, a single drive unit is provided to control the rotational speed of the rotatable jacket and to control the movement of at least one movable interlock member of the detangulation device. Advantageously, two drive units are provided: - One drive unit controls the rotational speed of one of the rotatable jackets and controls the movement of one of the two movable interlocking members of the detangulation device; - The second drive unit controls the rotational speed of the other of the rotatable jackets and controls the movement of the other of the two movable interlock members of the uncoupling device.

[0049] In one embodiment, at least one of the interlocking members of the detangulation device is integrally formed with the jacket upstream of the annular inlet into which a homogeneous collagen-elastin gel is introduced. In such an embodiment, at least one of the jackets has an upstream interlocking member of the upstream detangulation device of the extrusion system and a downstream portion that defines the annular inlet. Preferably, both interlocking members of the detangulation device are integrally formed with the jacket upstream of the annular inlet.

[0050] The projections of such integrally formed interlocking members may be arranged coaxially with the food dough extrusion passage or perpendicular to it.

[0051] In embodiments, the jacket has a conical portion defining part of the annular band, such that the annular band includes an acute angle of 30-60° with the co-extrusion axis. This creates a longer pathway for gel than for food dough. This is advantageous in embodiments where time is required to generate the oriented collagen-elastin gel in the annular band. In embodiments, the jacket has a cylindrical portion defining part of the annular band, such that the annular band is parallel to the co-extrusion axis. It is conceivable that the jacket has a conical portion at the annular band inlet and a downstream cylindrical portion at the annular band outlet.

[0052] In embodiments, at least one of the jackets has a profiled surface portion in the annular band. For example, the surface structure and roughness may affect the shear force transmitted to the gel. In embodiments, a flow-guiding profile is provided having rising and falling jacket surface portions, which also have an effect on the gel flow and the resulting gel casing.

[0053] In the embodiment, at least one of the jackets is replaceable. By replacing the jackets, the contact surfaces of the inner and / or outer jackets may change, while different contact surfaces will also have different effects on the gel fluid flowing along the surface. [Examples]

[0054] Collagen-rich gels are prepared by crushing the ends of thawed and shaken short casings, treating them in 0.3 M NaOH for 40 hours, washing them, mincing them to an average size of 2 mm, acid treating them in lactic acid for 48 hours, and then performing colloid milling to obtain a dispersion. Elastin-rich gels are prepared in a similar manner, starting from dissected bladder.

[0055] The blended gel and its blend are extruded onto food dough using an extrusion system in which the gel is subjected to a de-entanglement treatment. The resulting encapsulated food is brined, dried, and smoked using a standardized protocol, for example, as disclosed in International Publication No. 2021 / 096358. The food properties of heat-treated food having the gel casing according to the present invention have been found to be better than those of products having known gel casings. [Brief explanation of the drawing]

[0056] The present invention will be further illustrated with reference to the drawings.

[0057] [Figure 1] Figure 1 is a side view of the innovative extrusion system. [Figure 2] Figures 2a and 2b are detailed diagrams of the extrusion system shown in Figure 1. [Figure 3] Figures 3a and 3b are detailed views of the interlocking members of the extrusion system shown in Figures 1 and 2. [Figure 4] Figure 4 is a more detailed cross-sectional view of the extrusion system shown in Figures 1-3. [Figure 5] Figures 5a-5c are schematic diagrams of semi-finished gels, homogeneous collagen-elastin gels, and oriented collagen-elastin gels. [Modes for carrying out the invention]

[0058] Figure 1 schematically illustrates the extrusion system 1 according to the present invention for the continuous production of food products having a collagen-elastin gel casing, schematically indicated by the reference numeral "10" on the right side of Figure 1. The co-extruded food product 10 coming out of the innovative extrusion system 1 is further transported. In subsequent processes, for example, crosslinking occurs, forming a solid protective layer. This system is particularly suitable for the production of co-extruded food products, especially sausages.

[0059] The extrusion system 1 has a co-extruder for forming continuous food dough strands 3, and on its outside there is a gel layer 4 substantially uniformly distributed on the strands 3.

[0060] Food dough 3, for example, meat dough or sausage dough, is supplied into the food dough inlet 5a of the food dough extrusion passage 5, as indicated by the arrow in the left portion of the figure. The food dough extrusion passage 5 defines the co-extrusion axis A, as shown in Figures 2 and 4. The food dough extrusion passage 5 has an opposing food dough outlet 5b.

[0061] As shown in Figures 2 and 4, two co-extrusion jackets 28, 29 are arranged coaxially with the food dough extrusion passage 5. At least one of the jackets 28, 29 is rotatable around the co-extrusion axis A. The jackets define an annular band 41 between them, which has an annular band inlet 41a for introducing a liquid coating material, in this case gel E2. Rotation of at least one of the jackets causes the gel to be oriented, thereby transforming the introduced gel, such as gel E2 depicted in Figure 5b, into an oriented gel E3 as depicted in Figure 5c. In particular, the rotation generates shear forces on the fibers in the gel, causing them to be oriented. In embodiments with counter-rotating jackets, the shear forces in the outer region of the gel cause a counter-alignment with the fibers in the inner region of the gel, creating a network of oriented fibers. The annular band has opposing annular band outlets 41b for discharging the oriented gel as a thin layer into a continuous strand 3 (which deposits on the food dough 3 coming out of the food dough outlet 5b to form a food having a gel casing).

[0062] In the illustrated embodiment, the jackets 28, 29 have conical portions that define the angular portion 41' of the annular band, such that the angular portion of the annular band includes an acute angle of 30 to 60° with respect to the co-extrusion axis. Adjacent to the annular band exit 41b, the jacket has a parallel portion that defines the annular band portion 41'' parallel to the co-extrusion axis A.

[0063] The innovative extrusion system 1 further includes a detangling device 9. In the illustrated embodiment, the detangling device 9 is adjacent to the cooperating jackets 28, 29, in series with the cooperating jackets 28, 29, and provided upstream of the cooperating jackets 28, 29.

[0064] In Figures 2a and 2b, it is visible that the extrusion system 1 is equipped with a supply aperture 21 for supplying the gel, in this case the semi-finished gel E1 shown in Figure 5a. Due to the composition of the gel, fibrous entanglement occurs over time, particularly during storage. In the disclosed embodiment shown in Figure 2b, it can be seen that a detangler inlet 19a for the semi-finished gel is provided behind the aperture 21. Two rings 22, 23 are positioned substantially concentrically around a central axis A. During operation, the rings are arranged to rotate, for example, in opposite directions. The rotation rate may be, for example, on the order of 200 revolutions per minute.

[0065] In Figures 3a and 3b, the rings 22 and 23 are shown in a perspective view with them removed. Interlocking members 24, 25, 26 and the rim 27, implemented in the form of teeth that lean against each other, are visible. Here, the teeth are embodied as rectangular projections resembling a chest wall with gunports. Other configurations, such as triangular projections and / or gunported edges with gaps, are also conceivable. The interlocking members 24, 25, 26 define a labyrinth 40 between them. In the illustrated embodiment, the rings 22 and 23 are detachably connected to jackets 28 and 29. In the embodiment, the jackets rotate in opposite directions, with jacket 28 (shown in shaded in Figure 2b) rotating in a first direction and jacket 29 (shown with a checkerboard pattern in Figure 2b) rotating in the opposite direction. Jackets 28 and 29 are driven by external drive means (not shown) and rotate within the housing 30. Preferably, the device is made of stainless steel.

[0066] Figure 4 shows a cross-sectional view of an enlarged section of the extrusion system 1 shown in Figure 2b. This illustrates how the gel E1 is fed into the detangler inlet 9a via the channel 6 and the supply opening 21, and then fed into the annular inlet between the cooperating jackets via a labyrinth 40 formed between interlocking members of counter-rotating rings 22, 23, each fitted with teeth 24, 25, 26. The movement of at least one of the interlocking members exerts mechanical treatment on the semi-finished gel E1 in the labyrinth, reducing the fibrous clumps FC in the gel, thereby converting the semi-finished gel into a homogeneous collagen-elastin gel E2 as shown in Figure 5b. The mechanical treatment involves very high shear forces that cause detangler. These shear forces exceed the forces of the jackets and cause the orientation of fibers in the gel.

[0067] In the ring zones 41', 41'', the introduced homogeneous collagen-elastin gel E2 is converted into oriented collagen-elastin gel E3. This oriented collagen-elastin gel is discharged through the ring zone outlet 41b and deposits on the food dough 3 coming out of the food dough outlet, forming a food product with a gel casing.

[0068] The typical size of the ring band 41 is approximately 0.35 mm, but this depends on the desired thickness of the layer of coating material being manufactured.

Claims

1. A method for producing a semi-finished gel suitable for use in the preparation of food gel casings, the method comprising providing the semi-finished gel having collagen and elastin: The process involves providing a first (collagen-rich) natural tissue, such as beef cattle split, and a second (elastin-rich) natural tissue, such as a bladder. The ratio of the weight of collagen in the first (collagen-rich) natural tissue to the amount of collagen in the second (elastin-rich) natural tissue exceeds 1. The ratio of the weight of elastin in the second (elastin-rich) natural tissue to the amount of elastin in the first (collagen-rich) natural tissue exceeds 1. The first natural tissue and the second natural tissue are subjected to chemical treatment to provide a first natural tissue gel and a second natural tissue gel, respectively, and the first natural tissue gel and the second natural tissue gel are blended. or The combination of the first natural tissue and the second natural tissue is subjected to chemical treatment. The aforementioned method.

2. The method according to claim 1, further comprising a physical dissociation treatment for providing a homogeneous collagen-elastin gel.

3. The method according to any of the preceding claims, wherein the ratio of the second natural tissue gel to the first natural tissue gel, or the ratio of the second natural tissue to the first natural tissue, when blending can be selected from 100:0 to 10:90, 80:20, and 75:

25.

4. (A) The second natural tissue gel is present in an amount exceeding 50 wt%, 60 wt%, 65 wt%, 70 wt%, and 75 wt%, and more preferably at least 80 wt%, 85 wt%, and 90 wt%, calculated based on the total amount of the semi-finished gel; (B) The second natural tissue is present in amounts exceeding 50 wt%, 60 wt%, 65 wt%, 70 wt%, and 75 wt%, and more preferably at least 80 wt%, 85 wt%, and 90 wt%, calculated based on the total amount of the combination of the first natural tissue and the second natural tissue. The method according to any of the prior claims.

5. The chemical treatment is a process sequence having the following steps, where the steps are: (a) the step of grinding the first natural tissue and / or the second natural tissue to provide a grinding product; (b) optionally, the step of subjecting the pulverized product of step (a) to a caustic alkali solution treatment to provide a caustic alkali solution treatment product, (c) optionally a step of mincing the product of step (a) or (b) to obtain a minced product; (d) optionally an acidification step of the product of step (a), (b), or (c) for obtaining an acid treatment product, and (e) A step of providing an aqueous dispersion of the product of step (a), (b), (c), or (d), (f) The step of obtaining the semi-finished gel suitable for use in the preparation of food gel casings, The method according to any of the prior claims.

6. The method according to any of the preceding claims, wherein step (a) yields a pulverized product having an average dimension of 0.1 to 5 cm, preferably 0.5 to 3 cm.

7. The method according to any one of the preceding claims, wherein step (b) is carried out in an aqueous solution of a strong base, preferably 0.1 to 1.0 M of a strong base.

8. The method according to claim 7, wherein step (b) is carried out in an aqueous solution of a strong base for a period of 4 to 100 hours.

9. The method according to any of the preceding claims, wherein step (c) provides a minced product having an average dimension of 0.1 to 0.4 cm.

10. The method according to any of the preceding claims, wherein step (d) uses an acid selected from the group consisting of lactic acid, acetic acid, hydrochloric acid, and mixtures derived therefrom.

11. The method according to any of the preceding claims, wherein the dispersed product in step (c) is subjected to milling and / or homogenization.

12. The method according to any of the preceding claims, wherein the first natural tissue gel and the second natural tissue gel are formed in separate steps.

13. The method according to any one of the preceding claims, wherein the first natural tissue gel and the second natural tissue gel are combined to form the semi-finished gel.

14. A semi-finished gel suitable for use as a food gel casing, obtainable by the methods of claims 1 to 13.

15. A method for producing an oriented collagen-elastin gel suitable for forming a food having a gel casing, the method being: - The step of providing a semi-finished gel as defined in claim 15, - The process includes the step of subjecting the semi-finished gel to a de-entanglement treatment in the extrusion system (1) described in claim 16 to provide an oriented collagen-elastin gel (E3), The aforementioned method.

16. An extrusion system (1) for the continuous production of a food product (10) having a collagen-elastin gel casing, wherein the system is: - It has a food dough extrusion passage (5) that defines a co-extrusion shaft (A), and the food dough extrusion passage (5) has a food dough inlet (5a) and an opposing food dough outlet (5b); - The apparatus has two cooperating jackets (28, 29) arranged coaxially with the food dough extrusion passage (5), at least one of which is rotatable around the co-extrusion axis, the jackets having annular inlets (41a) for introducing gel (E2) between them, the rotation of at least one of the jackets causing the gel to be oriented, thereby converting the introduced gel into an oriented gel (E3), the annulars having opposing annular outlets (41b) for discharging the oriented gel; the discharged oriented gel deposits on the food dough (3) coming out of the food dough outlet to form a food having a gel casing; The system is further characterized by having an upstream detangulation device (9) adjacent to and in series with the aforementioned cooperating jacket, the detangulation device (9) being: - It has a detangulation device inlet (19a) for the semi-finished gel (E1); - The device has interlocking members (24, 25, 26) which define a labyrinth (40) between them, and at least one of the interlocking members is movable in the labyrinth to perform mechanical treatment on the semi-finished gel (E1) to reduce fibrous clumps (FC) in the gel, thereby converting the semi-finished gel into a homogeneous collagen-elastin gel (E2); - Having a dissociation device outlet (19b) for the homogeneous collagen-elastin gel which is introduced between the two cooperating jackets to be converted into an oriented collagen-elastin gel (E3), The aforementioned system.

17. The system according to claim 16, wherein the interlocking member of the disentanglement device has a row of projections (24, 25, 26), for example, tooth-shaped projections, for example, serrated edges.

18. The system according to claim 16 or 17, wherein the interlock members (24, 25, 26) are arranged coaxially with the co-extrusion shaft, and the interlock members are rotatable, for example, in reverse, around the co-extrusion shaft.

19. The system according to any one of the preceding claims 16 to 18, wherein the interlock members (24, 25, 26) of the unclasping device (9) are integrally formed with the jacket (28, 29) upstream of the ring band inlet (41a).

20. The system according to any one of the preceding claims 16 to 19, wherein the jacket has a conical portion that defines the angular portion of the ring band (41'), and the angular portion of the ring band includes an acute angle of 30 to 60° with the co-extrusion axis.

21. A method for the continuous production of a food having a gel casing, using the extrusion system of claim 16, the method being: - The procedure includes the step of introducing a semi-finished gel into the dissociation device; - The aforementioned movable interlock member of the dissociation device performs a continuous mechanical treatment on the semi-finished gel, thereby reducing the fibrous mass in the semi-finished gel and converting the semi-finished gel into a homogeneous collagen-elastin gel; - The process includes the step of introducing food dough into the food dough inlet; - The procedure includes the step of introducing the homogeneous collagen-elastin gel into the ring inlet when the dissociative device leaves the outlet; - The process includes the step of oriented the homogeneous collagen-elastin gel in the ring band between the jackets, thereby converting the introduced homogeneous collagen-elastin gel into an oriented collagen-elastin gel. - The step of discharging the oriented collagen-elastin gel onto the food dough coming out of the food dough outlet to form a food having a collagen-elastin gel casing, The aforementioned method.

22. A food product having a co-extruded food dough and a collagen-elastin gel casing, produced in the system described in claim 16.

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