Method for producing fiber assembly, and fiber assembly

Abstract

The present invention provides a method for producing a fiber assembly suitable for reproducing the texture of meat to be imitated. A method for producing a fiber assembly according to the present invention comprises: a step A for bringing a plurality of fibers containing a divalent metal salt of alginic acid into contact with a chelating agent; and a step B for binding at least two fibers among the plurality of fibers to each other by decomposing the chelating agent and / or mixing with a compound containing a divalent metal ion after the step A.

Description

Method for manufacturing fiber assembly, and fiber assembly

[0001] The present invention relates to a method for producing a fiber assembly, and to a fiber assembly.

[0002] In recent years, with the rise in the world population, it is expected that the demand for meat will increase. In order to meet the future increase in meat demand, it is not enough to simply increase the production efficiency of conventional protein sources; the development of new protein sources is essential. Examples of new protein sources include alternative foods such as plant meat produced from plants, meat produced from insects, and cultured meat produced by culturing microorganisms or cells themselves. These alternative foods are also attracting attention from the perspective of animal welfare. Patent Document 1 discloses a dried meat-like protein processed food as an example of an alternative food.

[0003] "Plant-based meat" is a processed food made from plant proteins such as soybeans, to which additives are added, and is also known as "fake meat." "Cultured meat" refers to meat made by culturing muscle cells using regenerative medicine technology, and is also known as "cultured meat" or "clean meat."

[0004] Japanese Patent Application Laid-Open No. 2022-118655

[0005] In recent years, fiber aggregates (fiber aggregates) have been considered as food substitutes. Fiber aggregates have the advantage of being able to easily imitate chunks of meat of a certain size, such as steak, sashimi, and fillets.

[0006] In a fiber assembly, if the fibers are not fixed, they tend to be difficult to maintain their shape. One possible method for fixing the fibers is to fill the spaces between the fibers with a binder. When the fibers contain proteins, it is possible to use an enzyme (protein cross-linking enzyme) such as transglutaminase, which cross-links proteins, to bond the fibers together and thereby fix the fibers. However, according to the inventors' research, these methods have room for improvement in terms of reproducing the texture of the meat to be imitated.

[0007] Therefore, an object of the present invention is to provide a method for producing a fiber aggregate suitable for reproducing the texture of the meat to be imitated.

[0008] As a result of extensive research, the inventors have discovered that methods using binders or protein cross-linking enzymes do not provide sufficient strength to the fiber aggregate after treatment, making it difficult to reproduce the texture of the target meat. Based on this finding, the inventors have furthered their research and discovered that treating fibers containing a divalent metal salt of alginic acid with a chelating agent to bond the fibers together improves the strength of the fiber aggregate, thereby completing the present invention.

[0009] The present invention provides a method for producing a fiber assembly, comprising: a step A of contacting a plurality of fibers containing a divalent metal salt of alginic acid with a chelating agent; and a step B of bonding at least two of the plurality of fibers to each other by decomposing the chelating agent after the step A and / or mixing the chelating agent with a compound containing a divalent metal ion.

[0010] Furthermore, the present invention provides a fiber assembly comprising: a plurality of fibers containing a divalent metal salt of alginic acid; and a decomposition product of a chelating agent, wherein at least two of the plurality of fibers are bonded to each other.

[0011] The present invention further provides a fiber assembly comprising a plurality of fibers containing a divalent metal salt of alginic acid, at least two of the plurality of fibers being bonded to each other, and having a tear strength of 0.03 N / mm or more as measured by the following test. Test: A plate-shaped test piece is cut out from the fiber assembly saturated with water. Two hooks (outer diameter 3.0 mm) are pierced into the test piece and penetrated in the thickness direction of the test piece. The two hooks are pulled away from each other at a tensile speed of 2.0 mm / sec, and the test piece is torn. The tear strength is determined by dividing the maximum load (N) by the thickness (mm) of the test piece.

[0012] According to the present invention, a method for producing a fiber aggregate suitable for reproducing the texture of meat to be imitated can be provided.

[0013] 1 is a diagram for explaining a method for manufacturing fibers contained in a fiber assembly, a diagram for explaining a method for measuring the tear strength of a fiber assembly, and a microscope image showing a cross section of a fiber assembly of Example 2.

[0014] A method for producing a fiber assembly according to a first aspect of the present invention includes: step A of contacting a plurality of fibers containing a divalent metal salt of alginic acid with a chelating agent; and step B of bonding at least two of the plurality of fibers to each other by decomposing the chelating agent after step A and / or mixing the chelating agent with a compound containing a divalent metal ion.

[0015] In a second aspect of the present invention, for example, in the production method according to the first aspect, in the step A, the chelating agent forms a complex with a divalent metal ion contained in the divalent metal salt, and in the step B, the complex is decomposed by decomposition of the chelating agent.

[0016] In a third aspect of the present invention, for example, in the manufacturing method according to the first or second aspect, in step A, the surface of the fiber is sol-formed by contact with the chelating agent, and in step B, the surface of the fiber is gel-formed by decomposition of the chelating agent and / or mixing with the compound.

[0017] In a fourth aspect of the present invention, for example, in the manufacturing method according to any one of the first to third aspects, the fibers contain water, and in the step B, the chelating agent is hydrolyzed by the water contained in the fibers.

[0018] In a fifth aspect of the present invention, for example, in the production method according to any one of the first to fourth aspects, the chelating agent comprises a condensed phosphate compound.

[0019] In a sixth aspect of the present invention, for example, in the production method according to any one of the first to fifth aspects, the compound includes a calcium salt.

[0020] In a seventh aspect of the present invention, for example, in the production method according to the sixth aspect, the calcium salt includes at least one selected from the group consisting of calcium sulfate, calcium citrate, calcium carbonate, calcium lactate, and calcium chloride.

[0021] A fiber assembly according to an eighth aspect of the present invention comprises a plurality of fibers containing a divalent metal salt of alginic acid and a decomposition product of a chelating agent, and at least two of the plurality of fibers are bonded to each other.

[0022] In a ninth aspect of the present invention, for example, in the fiber assembly according to the eighth aspect, the chelating agent includes a condensed phosphate compound, and the decomposition product includes at least one selected from the group consisting of an orthophosphate compound and a pyrophosphate compound.

[0023] In a tenth aspect of the present invention, for example, in the fiber assembly according to the eighth or ninth aspect, the content of the decomposition products is 10 wtppm or more.

[0024] A fiber assembly according to an eleventh aspect of the present invention comprises a plurality of fibers containing a divalent metal salt of alginic acid, at least two of the plurality of fibers being bonded to each other, and has a tear strength of 0.03 N / mm or more as measured by the following test. Test: A plate-shaped test piece is cut out from the fiber assembly saturated with water. Two hooks (outer diameter 3.0 mm) are pierced into the test piece and penetrated in the thickness direction of the test piece. The two hooks are pulled away from each other at a tensile speed of 2.0 mm / sec, and the test piece is torn. The tear strength is determined by dividing the maximum load (N) by the thickness (mm) of the test piece.

[0025] In a twelfth aspect of the present invention, for example, in the fiber assembly according to the eleventh aspect, the tear strength is 3.00 N / mm or less.

[0026] In a thirteenth aspect of the present invention, for example, the fiber assembly according to any one of the eighth to twelfth aspects is edible.

[0027] In a fourteenth aspect of the present invention, for example, in the fiber assembly according to any one of the eighth to thirteenth aspects, the fibers further contain non-animal protein.

[0028] In a fifteenth aspect of the present invention, for example, in the fiber assembly according to any one of the eighth to fourteenth aspects, the average fiber diameter of the plurality of fibers is 1 cm or less.

[0029] The present invention will be described in detail below, but the following description is not intended to limit the present invention to a specific embodiment.

[0030] <Method for Producing a Fiber Assembly> The method for producing a fiber assembly of this embodiment includes step A: contacting a plurality of fibers containing a divalent metal salt of alginic acid with a chelating agent; and step B: bonding at least two of the plurality of fibers to each other by decomposing the chelating agent after step A and / or mixing with a compound C containing a divalent metal ion. This production method is suitable for producing a fiber assembly with sufficient strength. A fiber assembly with high strength is suitable for reproducing the texture of the meat to be imitated.

[0031] [Step A] In step A, first, fibers containing a divalent metal salt of alginic acid are prepared. Specifically, the fibers contain alginic acids including a divalent metal salt of alginic acid. Preferably, the fibers further contain water. Details of the fibers will be described later. Note that the divalent metal salt of alginic acid is typically a salt of alginic acid and a divalent metal ion. In this specification, "divalent metal salt of alginic acid" may be simply referred to as "alginate."

[0032] Next, a chelating agent is added to the plurality of fibers, and the fibers are kneaded to bring the plurality of fibers into contact with the chelating agent. A dispersion of the chelating agent in water may be added to the plurality of fibers. However, if the chelating agent contains a hydrolyzable compound (e.g., a condensed phosphate compound), it is preferable to add the dispersion to the fibers immediately after preparation. The plurality of fibers and the chelating agent are preferably kneaded so that the plurality of fibers are oriented in a single direction or in two or more directions. Note that step A may be performed using a molding die. Specifically, the plurality of fibers may be placed in the molding die, and then the chelating agent (or a dispersion containing the chelating agent) may be added to the molding die. The molding die may have, for example, a container having a shape similar to that of the meat to be simulated.

[0033] The chelating agent is preferably different from alginic acids. The chelating agent is preferably degradable, but in some cases may not be degradable. The chelating agent is preferably edible both before and after decomposition. The chelating agent preferably contains a condensed phosphate compound. Examples of condensed phosphate compounds include condensed phosphoric acid and condensed phosphate salts. Condensed phosphoric acid is a compound having a structure in which two or more, preferably three or more, orthophosphoric acids (H3PO4) are condensed. Examples of condensed phosphoric acid include metaphosphoric acid, polyphosphoric acid, and ultraphosphoric acid, with metaphosphoric acid being preferred. Metaphosphoric acid is represented by the general formula (HPO3) n (n is an integer of 3 or more), and polyphosphoric acid is a compound represented by the general formula H n+2 P n O 3n+1 (n is an integer of 2 or more, preferably 3 or more), and ultraphosphoric acid is a compound represented by nH2O.P2O5 (0<n<1).

[0034] The condensed phosphate is typically a salt of condensed phosphoric acid and a monovalent metal ion. Examples of the monovalent metal ion include alkali metal ions such as sodium ions and potassium ions, with sodium ions being preferred. The chelating agent preferably contains sodium metaphosphate as the condensed phosphate compound.

[0035] The chelating agent is not limited to condensed phosphate compounds. Other examples of the chelating agent include ethylenediaminetetraacetic acid (EDTA), gluconic acid, citric acid, and phytic acid.

[0036] The amount of chelating agent added is not particularly limited. The ratio P1 of the weight of the chelating agent added to the fibers to the weight of the fibers is, for example, 0.01 wt% or more, and may be 0.1 wt% or more, 0.2 wt% or more, 0.5 wt% or more, 1.0 wt% or more, 1.5 wt% or more, 2.0 wt% or more, or even 2.5 wt% or more. The upper limit of the ratio P1 may be, for example, 10 wt% or less, 8.0 wt% or less, or even 5.0 wt% or less. The ratio P1 tends to enable the strength of the fiber assembly to be appropriately adjusted.

[0037] Furthermore, the weight ratio T1 of the chelating agent added to the fiber to the alginic acids contained in the fiber is, for example, 0.01 or more, and may be 0.1 or more, 0.2 or more, 0.3 or more, 0.4 or more, or even 0.5 or more. The upper limit of the weight ratio T1 may be, for example, 3.0 or less, 2.0 or less, 1.0 or less, or even 0.9 or less.

[0038] As described below, the fiber preferably further contains a non-animal protein. The weight ratio T2 of the chelating agent added to the fiber to the non-animal protein contained in the fiber is, for example, 0.01 or more, and may be 0.05 or more, 0.08 or more, 0.10 or more, 0.15 or more, or even 0.20 or more. The upper limit of the weight ratio T2 is, for example, 0.50 or less, and may be 0.30 or less.

[0039] The chelating agent can contact the fibers and act on a portion of the alginate contained in the fibers (especially the alginate located near the surface of the fibers). Specifically, the chelating agent forms an ionic bond with the divalent metal ion contained in the alginate near the surface of the fibers to form a complex. This causes the fibers to partially solate. In other words, the surface of the fibers solates upon contact with the chelating agent. By carrying out step A, multiple fibers with solated surfaces can be brought into contact with each other.

[0040] [Step B] As described above, in step B, after step A, the chelating agent is decomposed and / or a compound C containing a divalent metal ion is mixed with a plurality of fibers. In step B, it is preferable to decompose the chelating agent, and it is more preferable to perform both the decomposition of the chelating agent and the mixing of compound C and fibers. In this case, the mixing of compound C and fibers may be performed while the decomposition of the chelating agent is progressing in step B, or may be performed after the decomposition of the chelating agent has progressed.

[0041] The decomposition of the chelating agent (particularly a condensed phosphate compound) is, for example, hydrolysis. For example, when the fiber contains water, the chelating agent may be hydrolyzed by the water contained in the fiber. In this case, the hydrolysis of the chelating agent tends to progress over time after step A is performed. For example, the hydrolysis of the chelating agent can be progressed by leaving the chelating agent in contact with the fiber for at least one minute, preferably at least one hour. The hydrolysis of the chelating agent is preferably carried out at room temperature (25°C), but may also be carried out in a heated environment. The hydrolysis of the chelating agent may also be carried out in an acidic or basic environment. In particular, when the chelating agent is a condensed phosphate compound, the hydrolysis of the chelating agent tends to be promoted in an acidic environment. Note that the decomposition of the chelating agent is not limited to hydrolysis and may be thermal decomposition, etc.

[0042] As the decomposition of the chelating agent progresses, the complex between the divalent metal ion and the chelating agent decomposes, causing the surface of the fiber to gel. Specifically, the surface gelation progresses when multiple fibers with solated surfaces are in contact with each other. At this time, alginic acid present near the surface of one fiber and alginic acid present near the surface of the other fiber form a crosslinked structure via the divalent metal ion derived from the complex. This causes the contacting fibers to bond together, forming a fiber aggregate.

[0043] As the decomposition of the chelating agent progresses, decomposition products of the chelating agent are generated. For example, when the chelating agent contains a condensed phosphate compound (particularly a condensed phosphate compound having a structure in which three or more orthophosphates are condensed), examples of the decomposition products of the chelating agent include orthophosphate compounds and pyrophosphate compounds.

[0044] The compound C and the fibers can be mixed, for example, by adding the compound C to a plurality of fibers and kneading them. A dispersion of the compound C in water may be added to the plurality of fibers. The plurality of fibers and the compound C are preferably kneaded so that the plurality of fibers are oriented in a single direction or in two or more directions. As in step A, the plurality of fibers and the compound C may be mixed using a molding die.

[0045] When multiple fibers are mixed with compound C, the divalent metal ions contained in compound C cause the surfaces of the fibers to gel. Specifically, the gelation of the surfaces progresses when multiple fibers with solated surfaces are in contact with each other. At this time, alginic acid present near the surface of one fiber and alginic acid present near the surface of the other fiber form a crosslinked structure via the divalent metal ions derived from compound C. This causes the contacting fibers to bond together, forming a fiber aggregate.

[0046] Examples of compound C containing a divalent metal ion include calcium salts, magnesium salts, iron (II) salts, and zinc salts. Compound C preferably contains a calcium salt. The calcium salt includes, for example, at least one selected from the group consisting of calcium sulfate, calcium citrate, calcium carbonate, calcium lactate, and calcium chloride, and calcium sulfate is particularly preferred.

[0047] The amount of compound C added is not particularly limited. The ratio P2 of the weight of compound C added to the fibers to the weight of the fibers is, for example, 0.01 wt % or more, and may be 0.1 wt % or more, 0.3 wt % or more, 0.5 wt % or more, 0.8 wt % or more, or even 1.0 wt % or more. The upper limit of ratio P2 is, for example, 10 wt % or less, 8.0 wt % or less, 5.0 wt % or less, or even 3.0 wt % or less. The strength of the fiber assembly tends to be appropriately adjusted by adjusting ratio P2.

[0048] Furthermore, the weight ratio T3 of the compound C added to the fiber to the alginic acids contained in the fiber may be, for example, 5.0 or less, 3.0 or less, or even 1.0 or less. The lower limit of the weight ratio T3 may be, for example, 0 or more, 0.05 or more, or even 0.10 or more.

[0049] As described below, the fiber preferably further contains a non-animal protein. The weight ratio T4 of the compound C added to the fiber to the non-animal protein contained in the fiber is, for example, 0.5 or less, or may be 0.3 or less, or even 0.1 or less. The lower limit of the weight ratio T4 is, for example, 0 or more, or may be 0.005 or more, or even 0.01 or more.

[0050] The weight ratio T5 of the compound C to the chelating agent added to the fiber is, for example, 2.0 or less, and may be 1.5 or less, or even 1.0 or less. The lower limit of the weight ratio T5 is, for example, 0 or more, and may be 0.05 or more, or even 0.1 or more.

[0051] According to step B, at least two fibers among the plurality of fibers can be bonded to each other by decomposition of the chelating agent and / or mixing with compound C. In step B, it is preferable that 10% or more of the fibers among the plurality of fibers are bonded to adjacent fibers, more preferably 50% or more of the fibers are bonded to adjacent fibers, and particularly preferably that substantially all of the fibers are bonded to adjacent fibers.

[0052] [Heating Step] The manufacturing method of this embodiment may further include a heating step of heating the fiber assembly obtained by steps A and B. The heating step may, for example, cause non-animal proteins contained in the fibers to associate, further improving the texture of the fiber assembly. The heating step may also serve as a sterilization treatment for the fiber assembly. The conditions for the heating step are not particularly limited, and may, for example, be a temperature of 50°C to 120°C and a time of 1 minute to 1 hour.

[0053] [Fiber] Next, the fiber used in step A will be described. In step A, the fiber contains a divalent metal salt of alginic acid (alginate). Specifically, the fiber has alginic acids containing alginate. The alginic acids preferably further contain alginic acid together with the alginate. The fiber preferably further contains non-animal protein and water in addition to the alginic acids.

[0054] (Alginic Acids) Alginic acids are components suitable for adjusting the elasticity of fibers and fiber aggregates.

[0055] Alginic acid is a polysaccharide found in seaweed and the like, and has structural units (M blocks) derived from β-D-mannuronic acid and structural units (G blocks) derived from α-L-guluronic acid. In alginic acid, each structural unit is bonded via a 1,4-glycosidic bond. The content of G blocks in alginic acid is not particularly limited, and is, for example, 30 mol% or more, preferably 40 mol% or more, and more preferably 50 mol% or more. The upper limit of the G block content may be 90 mol% or 80 mol%. The G block content may be 31 mol% to 63 mol%.

[0056] For example, in alginate, at least one G block contained in alginic acid forms an ionic bond with a divalent metal ion. In other words, in alginate, alginic acid at least partially forms a salt with a divalent metal ion. Alginate typically has a crosslinked structure via a divalent metal ion. Examples of divalent metal ions include calcium ions, magnesium ions, barium ions, iron ions, zinc ions, copper ions, and aluminum ions, with calcium ions being preferred.

[0057] In the water-saturated fiber, the alginic acid content r1 is, for example, 0.5 wt % or more in terms of sodium alginate. The preferred range of the content r1 and the method for measuring it can be described later for the content R1.

[0058] (Non-animal protein) Non-animal protein is a component suitable for adjusting the nutritional value of fiber or fiber aggregate. Non-animal protein refers to proteins other than animal proteins derived from animals.

[0059] The non-animal protein preferably includes a vegetable protein. Examples of the vegetable protein include soybean protein, pea protein, lentil protein, and other bean proteins; potato protein; seitan protein; amaranth protein; quinoa protein, and the like. The non-animal protein preferably includes at least one vegetable protein selected from the group consisting of soybean protein, pea protein, lentil protein, potato protein, seitan protein, amaranth protein, and quinoa protein, and particularly preferably includes soybean protein. Note that the non-animal protein is not limited to a vegetable protein. The non-animal protein may also include a protein derived from a fungus.

[0060] In the water-saturated fiber, the non-animal protein content r2 is, for example, 5.0 wt % or more. The preferred range of the content r2 and the method for measuring it can be described later with respect to the content R2.

[0061] (Water) In the fiber saturated with water, the moisture content r3 is, for example, 60 wt % or more. The preferred range of the moisture content r3 and the method for measuring it can be described later for the moisture content R3. Note that the fiber used in step A does not need to be saturated with water.

[0062] (Fiber Shape, etc.) The shape of the fiber is not particularly limited. The fiber is preferably a long fiber, but may be a short fiber. The fiber preferably does not have a branched structure.

[0063] The fiber diameter of the fibers is, for example, 1 cm or less, and may be 1 mm or less, 800 μm or less, 500 μm or less, 300 μm or less, 200 μm or less, or even 100 μm or less. Fibers with a small fiber diameter tend to facilitate the production of a fiber aggregate with a dense structure and facilitate the reproduction of the texture of chunks of meat. The lower limit of the fiber diameter of the fibers is, for example, 1 μm or more, and may be 5 μm or more, 10 μm or more, 30 μm or more, or even 50 μm or more. The fiber diameter of the fibers is preferably 50 μm to 200 μm. The fiber diameter can be determined by the following method. First, the fibers are observed using an optical microscope or a microscope. In the obtained microscopic image, the fiber diameter is measured using a scale such as a vernier caliper. The fiber diameter is measured at any number of measurement points (at least three points), and the average of the obtained measurements is considered to be the fiber diameter.

[0064] (Method for producing fibers) In this embodiment, the method for producing fibers includes a spinning step in which a mixed liquid containing, for example, a non-animal protein, a monovalent metal salt of alginic acid, and an alkali compound is ejected into a coagulation liquid to form fibers. The monovalent metal salt of alginic acid is typically a salt of alginic acid and a monovalent metal ion. In this specification, the "monovalent metal salt of alginic acid" may also be simply referred to as "alginate."

[0065] The spinning process can be carried out, for example, using a spinning apparatus 100 shown in Fig. 1. The spinning apparatus 100 includes a discharge section 10 that discharges the mixed liquid, a coagulation section 20 that contains a coagulation liquid 21 that coagulates the material discharged from the discharge section 10, and a winding section 30 that winds up the fiber 6 formed in the coagulation section 20. The discharge section 10, the coagulation section 20, and the winding section 30 are arranged, for example, in this order along the direction in which the fiber 6 is wound by the winding section 30 (direction X).

[0066] The discharge unit 10 has a storage unit 11 that stores the mixed liquid and a nozzle 13 that discharges the mixed liquid. A commercially available discharge device equipped with a gear pump or syringe pump can be used as the discharge unit 10. As described above, the mixed liquid stored in the storage unit 11 preferably contains a non-animal protein, an alginate, and an alkaline compound.

[0067] Examples of non-animal proteins contained in the above-mentioned mixture include those mentioned above for fiber. Non-animal proteins usually have a unique three-dimensional structure based on their amino acid sequence. However, in the above-mentioned mixture, the presence of alkaline compounds tends to destroy the three-dimensional structure of the non-animal proteins, causing the non-animal proteins to assume a string-like structure. In this specification, the destruction of the three-dimensional structure of non-animal proteins by alkaline compounds is sometimes referred to as "unfolding."

[0068] According to the inventors' research, by mixing non-animal protein with an alkaline compound and carrying out the spinning process while the non-animal protein is unfolded, it is easy to adjust the alginic acid content and moisture content in a water-saturated fiber aggregate (especially the fibers contained in the fiber aggregate) to high values.

[0069] Furthermore, by unfolding the non-animal protein, the solubility of the non-animal protein in the mixture tends to improve, making it easier to form fibers. In other words, the spinnability of the mixture tends to improve. When unfolded non-animal protein is used, the strength of the resulting fibers also tends to improve.

[0070] The content of non-animal protein in the mixed liquid is not particularly limited, and is, for example, 1.0 wt % to 30 wt %.

[0071] In the alginate (monovalent metal salt of alginic acid) contained in the mixed solution, examples of the monovalent metal ion include alkali metal ions such as sodium ions and potassium ions, with sodium ions being preferred. In the mixed solution, the alginate typically does not substantially contain divalent metal ions.

[0072] The alginate content in the mixed solution is preferably greater than 0.5 wt %, and may be 0.8 wt % or more, 0.9 wt % or more, 1.0 wt % or more, or even 1.1 wt % or more. The upper limit of the alginate content is not particularly limited, and may be, for example, 5.0 wt % or less. Note that if the alginate content is significantly less than 0.5 wt %, spinning of the fibers 6 tends to be difficult.

[0073] As described above, the alkaline compound is a component for unfolding non-animal proteins in the mixed solution. The alkaline compound is preferably edible. Examples of the alkaline compound include sodium hydroxide and sodium bicarbonate (baking soda), and sodium hydroxide is preferred. The content of the alkaline compound in the mixed solution is, for example, 10 wtppm to 5000 wtppm.

[0074] The mixed solution is preferably adjusted to a pH of 8 or higher with an alkaline compound. If the mixed solution has a pH of 8 or higher, non-animal proteins tend to be unfolded in the mixed solution. The pH of the mixed solution is preferably 8 to 13, and more preferably 9 to 11.

[0075] The mixed liquid preferably further contains water. The content of water in the mixed liquid is not particularly limited, and is, for example, 50 wt % to 98.5 wt %.

[0076] The mixture may further contain other components contained in the fiber aggregate, which will be described later (such as a softener and a lubricant).

[0077] In the discharge unit 10, the mixed liquid is sent from the storage unit 11 to the nozzle 13 and discharged from the nozzle 13 to the outside of the discharge unit 10 through the nozzle outlet. The discharge rate of the mixed liquid from the nozzle 13 is not particularly limited and is, for example, 0.1 to 10,000 mL / min. The size of the nozzle outlet can be adjusted appropriately depending on the fiber diameter of the target fiber 6. The nozzle 13 may have multiple discharge outlets. In this case, multiple fibers 6 can be produced at once by solidifying the material discharged from the nozzle 13. The number of discharge outlets in the nozzle 13 is not particularly limited and is, for example, 1 to 20,000. Using a nozzle 13 with a large number of discharge outlets and setting a high discharge rate of the mixed liquid allows the fibers 6 to be produced efficiently, improving productivity. The nozzle 13 is, for example, immersed in the coagulation liquid 21 contained in the coagulation unit 20.

[0078] The coagulation liquid 21 contained in the coagulation unit 20 can coagulate the discharged material (liquid mixture) by coming into contact with the discharged material from the nozzle 13. The fiber 6 is formed by coagulating the discharged material from the nozzle 13. The coagulation liquid 21 is typically an aqueous solution containing a coagulant.

[0079] The coagulation liquid 21 preferably contains a metal salt containing a divalent metal ion as a coagulant. Examples of such metal salts include chlorides such as calcium chloride and carbonates such as calcium carbonate. For example, a metal salt containing a divalent metal ion generates divalent metal ions by dissolving in the coagulation liquid 21. The divalent metal ions can form ionic bonds with the G-blocks of the alginate. Specifically, the metal ions (monovalent metal ions) contained in the alginate are exchanged for divalent metal ions in the mixed solution, thereby crosslinking multiple alginic acid molecules via the divalent metal ions. This crosslinking reaction promotes gelation of the material discharged from the nozzle 13, resulting in the production of the fibers 6. The content of the coagulant in the coagulation liquid 21 is not particularly limited and may be, for example, 0.1 wt% to 10 wt%.

[0080] The coagulation liquid 21 preferably further contains an acid compound in addition to the coagulant (metal salt). When the coagulation liquid 21 contains an acid compound, the three-dimensional structure of the unfolded non-animal protein can be restored by contacting the material discharged from the nozzle 13 with the coagulation liquid 21. In this specification, the restoration of the three-dimensional structure of the unfolded non-animal protein may be referred to as "refolding."

[0081] The acid compound is preferably edible. Examples of the acid compound include, but are not limited to, citric acid and acetic acid, with citric acid being preferred. The content of the acid compound in the coagulation liquid 21 is not particularly limited and is, for example, 0.1 wt % to 10 wt %.

[0082] The coagulation liquid 21 may contain a mixture of an acid compound and an alkaline compound. The alkaline compound contained in the coagulation liquid 21 is not particularly limited, and examples thereof include sodium hydroxide and sodium bicarbonate.

[0083] The pH of the coagulation liquid 21 is preferably adjusted to 6 or less with an acid compound or a mixture of an acid compound and an alkaline compound. The pH of the coagulation liquid 21 is particularly preferably 1 to 6. Within the above pH range, non-animal proteins can be refolded.

[0084] The fiber 6 formed in the coagulation section 20 is sent to the winding section 30. The spinning apparatus 100 may further include free rollers 40 and 41 for sending the fiber 6 to the winding section 30. The free roller 40 is, for example, disposed in the coagulation liquid 21 and is approximately 10 cm to 10 m away from the nozzle 13. The fiber 6 passes through the free roller 40 and is then sent to the outside of the coagulation section 20. The fiber 6 sent to the outside of the coagulation section 20 passes through the free roller 41 and is then sent to the winding section 30. Note that the spinning apparatus 100 does not necessarily have to include the free rollers 40 and 41.

[0085] The winding unit 30 has a bobbin 31 that winds the fiber 6 formed in the coagulation unit 20, and a guide 35 for traversing the fiber 6 when winding the fiber 6. The rotation speed of the bobbin 31 is not particularly limited and is, for example, 0.1 to 500 rps. The winding speed of the fiber 6 by the bobbin 31 is not particularly limited and is, for example, 0.1 to 500 m / min. The number of traverses per second is not particularly limited and is, for example, 0.1 to 10. The traverse speed is not particularly limited and is, for example, 10 to 500 mm / sec. The traverse speed refers to the average speed of the reciprocating motion of the guide 35 in a direction perpendicular to the direction X. The winding unit 30 does not necessarily have to have the guide 35.

[0086] In this embodiment, the fiber manufacturing method preferably further includes a washing step of washing the fibers 6 removed from the coagulation liquid 21. The washing step makes it possible to remove excess coagulant, acid compounds, and the like adhering to the surfaces of the fibers 6. The temperature of the washing liquid used in the washing step is, for example, room temperature (25°C). The time for which the fibers 6 are in contact with the washing liquid is not particularly limited and is, for example, 1 second to 1 hour.

[0087] In the cleaning step, it is preferable to use an alkaline aqueous solution or water as the cleaning liquid. The alkaline aqueous solution is, for example, an aqueous solution containing an alkaline compound, and the alkaline compound may be any of those mentioned above. The content of the alkaline compound in the alkaline aqueous solution is not particularly limited, and is, for example, 0.05 wt % to 10 wt %. The alkaline aqueous solution is preferably adjusted to a pH of 8 or higher, and particularly preferably a pH of 8 to 11.

[0088] The washing step may be performed before the fiber 6 is wound onto the bobbin 31, or after the fiber 6 is wound onto the bobbin 31. As an example, the washing step may be performed using a washing tank (not shown) disposed between the coagulation unit 20 and the winding unit 30 and containing a washing liquid. The washing tank allows the fiber 6 sent from the coagulation unit 20 to be brought into contact with the washing liquid, thereby washing the fiber 6. The washed fiber 6 is sent from the washing tank to the winding unit 30 and wound onto the bobbin 31. As another example, the washing step may be performed by pouring the washing liquid onto a wound body produced by winding the fiber 6 onto the bobbin 31, or by immersing the wound body together with the bobbin 31 in the washing liquid. Furthermore, the washing step may be performed by bringing the fiber 6 removed from the bobbin 31 into contact with the washing liquid.

[0089] In this embodiment, the fiber manufacturing method may further include a drying step of drying the fiber 6. The drying step allows the moisture content of the fiber 6 to be adjusted to a desired value. The conditions for the drying step are not particularly limited, and the fiber 6 may be dried, for example, by leaving the fiber 6 at room temperature (25°C). The drying step may involve freeze drying or heat drying. When heat drying is performed, the heating temperature of the fiber 6 is, for example, 50°C to 120°C. Before heat drying, the fiber 6 may be immersed in alcohol such as ethanol to replace the water contained in the fiber 6 with the alcohol.

[0090] [Fiber Assembly] As described above, a fiber assembly can be produced by steps A and B. The fiber assembly is an assembly in which the above-described plurality of fibers 6 are assembled. The fiber assembly may contain fibers other than the fibers 6, or may not contain other fibers. The fiber assembly may contain multiple types of fibers 6.

[0091] The average fiber diameter of the plurality of fibers 6 contained in the fiber assembly is, for example, 1 cm or less, and may be 1 mm or less, 800 μm or less, 500 μm or less, 300 μm or less, 200 μm or less, or even 100 μm or less. The lower limit of the average fiber diameter is, for example, 1 μm or more, and may be 5 μm or more, 10 μm or more, 30 μm or more, or even 50 μm or more. The average fiber diameter is preferably 50 μm to 200 μm. The average fiber diameter means the average value of the diameters determined by the above-described method for any number (at least five) of fibers 6.

[0092] In the fiber assembly, at least two fibers 6 out of the plurality of fibers 6 are bonded to each other. The fibers 6 are typically bonded directly to each other, and no binder or the like is present at the bonded portions between the fibers 6. In the fiber assembly, it is preferable that 10% or more of the fibers 6 out of the plurality of fibers 6 are bonded to adjacent fibers 6, more preferably 50% or more of the fibers 6 are bonded to adjacent fibers 6, and particularly preferably that substantially all of the fibers 6 are bonded to adjacent fibers 6.

[0093] In the fiber assembly, the plurality of fibers 6 are preferably oriented. The plurality of fibers 6 may be oriented in a single direction or in two or more directions. The full width at half maximum (FWHM) of the orientation distribution of the plurality of fibers 6 is, for example, 10° or more, and may be 20° or more, 30° or more, 40° or more, 50° or more, 60° or more, 70° or more, or even 80° or more. In particular, the plurality of fibers 6 are preferably oriented in the same direction as the muscle fibers contained in the meat to be imitated.

[0094] The fiber assembly preferably contains fibers 6 as a main component. In this specification, "main component" means the component contained in the fiber assembly in the largest amount by weight. The content of fibers 6 in the fiber assembly is, for example, 60 wt % or more, and may be 80 wt % or more, 90 wt % or more, or even 95 wt % or more. In some cases, the fiber assembly may be composed substantially of fibers 6 alone.

[0095] In this embodiment, the fibers 6 are bonded to each other through steps A and B, but the composition and shape of the fibers 6 themselves are hardly changed by steps A and B. Therefore, the above description can be applied to the composition and shape of the fibers 6 contained in the fiber aggregate.

[0096] The fiber assembly, for example, contains alginic acids, non-animal protein, and water derived from the fiber 6. In a water-saturated fiber assembly, the alginic acid content R1, calculated as sodium alginate, is, for example, 0.5 wt% or more, and may be 1.0 wt% or more, 1.5 wt% or more, 1.8 wt% or more, 2.0 wt% or more, 2.3 wt% or more, 2.5 wt% or more, 2.8 wt% or more, 3.0 wt% or more, 3.1 wt% or more, 3.2 wt% or more, or even 3.3 wt% or more. The higher the alginic acid content R1, the more elastic the fiber assembly, which tends to improve the texture of the fiber assembly. If the alginic acid content R1, calculated as sodium alginate, is significantly lower than 0.5 wt%, the fiber assembly tends to have a brittle texture. The upper limit of the alginic acid content R1, calculated as sodium alginate, is, for example, 10 wt % or less, and may be 8.0 wt % or less, 5.0 wt % or less, or even 4.0 wt % or less. The alginic acid content R1, calculated as sodium alginate, is preferably 2.0 wt % to 10 wt %. The weight ratio of the alginic acid, calculated as sodium alginate, to the solid content of the fiber assembly is, for example, 5 wt % to 40 wt %.

[0097] In this specification, "saturated with water" means that when a fiber assembly is immersed in water at 25° C. for 1 minute, the weight change rate of the fiber assembly is 0.1% or less, preferably 0.05% or less, and more preferably 0.01% or less. The weight change rate of the fiber assembly means the ratio (100×|W2-W1| / W1) of the difference between the weight W1 (g) of the fiber assembly before immersion in water and the weight W2 (g) of the fiber assembly after immersion in water.

[0098] The alginic acid content R1 can be determined by the colorimetric method described in "Methods for Analyzing Food Additives in Foods," Food Chemistry Division, Environmental Health Bureau, Ministry of Health, Labor and Welfare, 2nd Edition, pp. 90-92, 2000. In the colorimetric method, alginic acids are converted to sodium alginate during preparation of the measurement sample, and therefore the alginic acid content R1 is determined as a value converted to sodium alginate.

[0099] As described above, the fibers contained in the fiber assembly of this embodiment can be produced, for example, by discharging a mixed solution containing a non-animal protein, a monovalent metal salt of alginic acid, and an alkali compound into a coagulation liquid. In this case, the solids of the mixed solution (particularly the non-animal protein and the monovalent metal salt of alginic acid) are unlikely to dissolve into the coagulation liquid, so the formed fibers tend to contain the solids of the mixed solution as is. When fibers are produced using sodium alginate as the monovalent metal salt of alginic acid, the alginic acid content R1, converted to sodium alginate, in a fiber assembly composed essentially of these fibers can be calculated as the product of the weight ratio C1 of the solids in the water-saturated fiber assembly and the weight ratio C2 of sodium alginate to the solids in the mixed solution. According to the inventors' studies, the content R1 calculated using this method tends to closely match actual measurements.

[0100] In a fiber assembly saturated with water, the non-animal protein content R2 is, for example, 5.0 wt% or more, and may be 8.0 wt% or more, 10 wt% or more, 13 wt% or more, 15 wt% or more, 18 wt% or more, or even 20 wt% or more. The non-animal protein content R2 is preferably higher than the alginic acid content R1. The upper limit of the non-animal protein content R2 is not particularly limited, and may be, for example, 27 wt% or less, 25 wt% or less, or even 24 wt% or less. The non-animal protein content R2 is preferably 10 wt% to 27 wt%. The weight ratio of non-animal protein to the solid content of the fiber assembly is, for example, 40 wt% to 95 wt%.

[0101] As described above, the fibers contained in the fiber assembly of this embodiment can be produced, for example, by discharging a mixed solution containing a non-animal protein, a monovalent metal salt of alginic acid, and an alkali compound into a coagulation liquid. Because the solids of the mixed solution (particularly the non-animal protein and the monovalent metal salt of alginic acid) are not easily dissolved into the coagulation liquid, the formed fibers tend to contain the solids of the mixed solution intact. Therefore, in a fiber assembly composed essentially of this fiber alone, the non-animal protein content R2 can also be calculated as the product of the weight ratio C1 of the solids in the water-saturated fiber assembly and the weight ratio C3 of the non-animal protein to the solids in the mixed solution. According to the inventors' studies, the content R2 calculated using this method tends to closely match actual measurements.

[0102] In the fiber assembly, the weight ratio T6 of alginic acids to non-animal proteins is, for example, 0.025 to 1.0, and may be 0.1 to 0.5.

[0103] In a fiber assembly saturated with water, the moisture content R3 is, for example, 60 wt% or more, and may be 65 wt% or more, 70 wt% or more, 71 wt% or more, 72 wt% or more, 73 wt% or more, 74 wt% or more, or even 75 wt% or more. The higher the moisture content R3, the more juicy and moist the fiber assembly becomes, which tends to improve the texture of the fiber assembly. The upper limit of the moisture content R3 may be, for example, 90 wt% or less, 88 wt% or less, 85 wt% or less, 83 wt% or less, or even 80 wt% or less. The moisture content R3 is preferably 60 wt% to 88 wt%, and more preferably 71 wt% to 80 wt%. The weight ratio of the solids content in a fiber assembly saturated with water is, for example, 12 wt% to 29 wt%, and preferably 20 wt% to 29 wt%. The weight percentage of solids may be 30 wt % to 40 wt %.

[0104] The moisture content R3 can be determined by the following method. First, a fiber assembly saturated with water is prepared, and its weight W3 (g) is measured. The weight W3 is preferably 1 g. Next, the fiber assembly is placed in a heating moisture meter and subjected to a heat treatment at 105°C. This heat treatment volatilizes the water contained in the fiber assembly. The heat treatment is continued until the rate at which the water in the fiber assembly decreases falls below 0.10 wt% / min. Based on the weight W3 and the weight W4 (g) of the fiber assembly after the heat treatment, the moisture content R3 can be calculated using the following formula: Moisture content R3 (wt%) = 100 x (weight W3 - weight W4) / weight W3

[0105] Note that the fiber aggregate may have a moisture content of less than 60 wt% as long as it is not saturated with water. In particular, during storage or transportation, a low moisture content in the fibers is preferable, and the moisture content may be, for example, 50 wt% or less, 30 wt% or less, 10 wt% or less, 5 wt% or less, 1 wt% or less, or even 0.1 wt% or less. Fiber aggregates with low moisture content are also suitable for use as scaffolding materials for producing cultured meat. On the other hand, fiber aggregates provided to consumers preferably have a moisture content of 60 wt% or more (particularly 65 wt% or more or 71 wt% or more). The upper limit of the moisture content of the fiber aggregate may be, for example, 90 wt% or less, 85 wt% or less, 83 wt% or less, or even 80 wt% or less.

[0106] The fiber assembly may further contain a decomposition product of the chelating agent produced in the above step B.

[0107] In another aspect, the present invention provides a fiber assembly comprising: a plurality of fibers (6) containing a divalent metal salt of alginic acid; and a decomposition product of a chelating agent, wherein at least two of the plurality of fibers (6) are bonded to each other.

[0108] As described above, when the chelating agent contains a condensed phosphate compound (particularly a condensed phosphate compound having a structure in which three or more orthophosphates are condensed), decomposition products of the chelating agent include orthophosphate compounds, pyrophosphate compounds, etc. In the fiber assembly of this embodiment, the decomposition products of the chelating agent preferably contain at least one selected from the group consisting of orthophosphate compounds and pyrophosphate compounds.

[0109] Examples of orthophosphate compounds include orthophosphoric acid and orthophosphate salts. Orthophosphate salts are typically salts of orthophosphoric acid and monovalent or divalent metal ions. Examples of monovalent metal ions include alkali metal ions such as sodium ions and potassium ions. Examples of divalent metal ions include calcium ions, magnesium ions, barium ions, iron ions, zinc ions, copper ions, and aluminum ions. Similarly, examples of pyrophosphate compounds include pyrophosphoric acid (HPO) and pyrophosphate salts. Pyrophosphate salts are typically salts of pyrophosphoric acid and monovalent or divalent metal ions. Examples of monovalent or divalent metal ions include those described above for orthophosphate salts.

[0110] The content of decomposition products of the chelating agent in the fiber assembly may be, for example, 10 wt ppm or more, 50 wt ppm or more, 100 wt ppm or more, 300 wt ppm or more, 500 wt ppm or more, or even 1000 wt ppm or more. The upper limit of the content of decomposition products may be, for example, 10 wt % or less, 8.0 wt % or less, 5.0 wt % or less, or even 1.0 wt % or less.

[0111] When the fiber assembly contains an orthophosphate compound as a decomposition product of a chelating agent, the content of the orthophosphate compound in the fiber assembly may be, for example, 10 wt ppm or more, 50 wt ppm or more, 100 wt ppm or more, or even 300 wt ppm or more. The upper limit of the content of the orthophosphate compound may be, for example, 10 wt % or less, 8.0 wt % or less, 5.0 wt % or less, or even 1.0 wt % or less.

[0112] When the fiber assembly contains a pyrophosphate compound as a decomposition product of a chelating agent, the content of the pyrophosphate compound in the fiber assembly may be, for example, 5 wt ppm or more, 10 wt ppm or more, 50 wt ppm or more, 100 wt ppm or more, or even 200 wt ppm or more. The upper limit of the content of the pyrophosphate compound may be, for example, 10 wt % or less, 8.0 wt % or less, 5.0 wt % or less, 1.0 wt % or less, 0.5 wt % or less, or even 0.1 wt % or less.

[0113] The fiber assembly may or may not further contain other components in addition to the above-mentioned components. Examples of other components include animal protein, lipids, alkaline compounds, coagulants, acid compounds, softeners, lubricants, binders, protein cross-linking enzymes, proteolytic enzymes, fragrances, seasonings, etc. In the fiber assembly, the fibers themselves may contain the above-mentioned other components.

[0114] Lipids include beeswax, phospholipids, and fatty acids. The alkaline compounds, coagulants, and acid compounds are derived from the materials used to produce the fibers. Lubricants include glycerin. Lubricants are suitable for preventing the fibers from coming into contact with free rollers, guides, and the like when winding the fibers.

[0115] It is preferable that the fiber assembly does not contain a binder, a protein cross-linking enzyme, a protease, or the like. As described above, according to the manufacturing method of this embodiment, a fiber assembly having sufficient strength can be produced without using a binder or a protein cross-linking enzyme. However, when an attempt is made to fix the fibers of a fiber assembly using a binder, the binder tends to become uneven and not uniform within the fiber assembly. Since the manufacturing method of this embodiment does not require the use of a binder, the problem of the binder being uneven within the fiber assembly can be avoided.

[0116] In a fiber assembly saturated with water, the content of other components may be, for example, 25 wt% or less, 20 wt% or less, 15 wt% or less, 10 wt% or less, 5 wt% or less, 1 wt% or less, or even 0.1 wt% or less.

[0117] The fiber assembly is typically edible. In this specification, "edible fiber assembly" means that the fiber assembly is composed only of substances approved as foods or food additives by the laws and regulations of each country. It is preferable that the fiber assembly is substantially free of components other than foods or food additives, such as plasticizers (softeners) and surfactants.

[0118] The shape of the fiber assembly is not particularly limited, and may be a sheet, cube, disk, or the like. Preferably, the fiber assembly has a shape similar to the meat to be imitated. Examples of the meat to be imitated include crustaceans, shellfish, fish, beef, pork, and poultry (especially chicken).

[0119] As described above, the fiber aggregate formed by the manufacturing method of this embodiment has high strength and tends to be suitable for reproducing the texture of the target meat. As an example, the tear strength of the fiber aggregate measured by the following test is 0.03 N / mm or more. According to the inventors' research, when the tear strength of the fiber aggregate is similar to that of the target meat, the texture of the fiber aggregate tends to be similar to that of the target meat. Test: A plate-shaped test specimen is cut from a water-saturated fiber aggregate. Two hooks (outer diameter 3.0 mm) are pierced into the test specimen and penetrated through the thickness of the test specimen. The two hooks are pulled away from each other at a tensile speed of 2.0 mm / sec to tear the test specimen. The tear strength is determined by dividing the maximum load (N) by the thickness (mm) of the test specimen.

[0120] In another aspect, the present invention provides a fiber assembly comprising a plurality of fibers 6 containing a divalent metal salt of alginic acid, at least two of the plurality of fibers 6 being bonded to each other, and having the above-mentioned tear strength of 0.03 N / mm or more.

[0121] The tear strength of a fiber assembly can be evaluated in detail by the following method. First, a fiber assembly saturated with water is prepared. Normally, even a dry fiber assembly with almost no water inside can be made into a water-saturated fiber assembly by immersing it in water at 25°C for 1 hour.

[0122] Next, a plate-shaped test piece is cut out from the fiber assembly. The shape of the test piece may be a disk, an elliptical plate, a rectangular plate, or the like. The thickness of the test piece is preferably about 10 mm. The size of the test piece other than the thickness is preferably adjusted to a range that does not affect the measurement results of the tear strength. When the fiber assembly is plate-shaped, the fiber assembly itself may be used as the test piece.

[0123] In the test piece, it is preferable that the plurality of fibers 6 are oriented, and it is preferable that each of the plurality of fibers 6 extends in the thickness direction of the test piece. However, in the test piece, at least a portion of the plurality of fibers 6 may not be oriented.

[0124] Next, as shown in FIG. 2, two hooks 2A and 2B are pierced into the test piece 1, and the two hooks 2A and 2B penetrate the test piece 1 in the thickness direction. FIG. 2 shows the state in which the elliptical plate-shaped test piece 1 is pierced by the two hooks 2A and 2B. The hooks 2A and 2B pierce the test piece 1, for example, near the center (center of gravity) of the test piece 1. Before the tensile test, it is preferable that the hooks 2A and 2B are in contact with each other (the initial distance between the hooks is 0 mm). The outer diameters of both hooks 2A and 2B (particularly the outer diameter of the portion in contact with the test piece 1) are 3.0 mm.

[0125] Next, a tensile test is performed in which the two hooks 2A and 2B are pulled away from each other. The tensile test can be performed using a commercially available tensile tester or texture analyzer. As an example, the tensile test may be performed by fixing one hook 2B to a fixing part 3 located below the test piece 1 and pulling the other hook 2A upward (FIG. 2). The tensile test is performed at a pulling rate of 2.0 mm / sec until the test piece 1 is torn. The tensile test is performed in an atmosphere of 25°C.

[0126] Next, a graph showing the relationship between load and time is created from the results of the tensile test, and the maximum load (N) is determined from the graph. The tear strength can be determined by dividing the maximum load (N) by the thickness (mm) of the test piece 1.

[0127] As described above, the tear strength of the fiber assembly is preferably 0.03 N / mm or more, and may be 0.05 N / mm or more, 0.08 N / mm or more, 0.10 N / mm or more, 0.13 N / mm or more, 0.15 N / mm or more, 0.18 N / mm or more, 0.20 N / mm or more, 0.23 N / mm or more, 0.25 N / mm or more, 0.28 N / mm or more, 0.30 N / mm or more, or even 0.33 N / mm or more. The upper limit of the tear strength of the fiber assembly is, for example, 3.00 N / mm or less, and may be 2.50 N / mm or less, 2.00 N / mm or less, 1.50 N / mm or less, 1.00 N / mm or less, 0.80 N / mm or less, or even 0.50 N / mm or less. The tear strength of the fiber assembly is preferably 0.08 N / mm to 0.50 N / mm.

[0128] The centrifugal separation rate of the fiber assembly is preferably 35% or less. The centrifugal separation rate of the fiber assembly may be 30% or less, 25% or less, 20% or less, or even 15% or less. The lower limit of the centrifugal separation rate of the fiber assembly is, for example, 5% or more, and may be 10% or more.

[0129] The centrifugal separation rate of a fiber assembly can be measured by the following method. First, the fiber assembly is cut to prepare a test piece with a weight W5 (g). The weight W5 is preferably 1 g. This test piece is packed into filter paper and placed in a 50 mL centrifuge tube. Next, using a commercially available high-speed micro refrigerated centrifuge, the test piece is centrifuged for 30 minutes at a centrifugal acceleration of 2200 G and a temperature of 4°C. This separates some of the water contained in the test piece. The centrifugal separation rate can be calculated using the following formula based on the weight W5 and the weight W6 (g) of the test piece after centrifugation: Centrifugal separation rate (%) = 100 × (weight W5 - weight W6) / weight W5

[0130] (Uses of Fiber Assembly) The fiber assembly obtained by the manufacturing method of this embodiment is suitable for reproducing the texture of the meat to be imitated. The fiber assembly is particularly suitable for use as a substitute food for meat from crustaceans, shellfish, fish, beef, pork, poultry (especially chicken), etc. In some cases, the fiber assembly can also be used as a scaffold for cultured meat. That is, cultured meat can be produced by attaching cells from crustaceans, shellfish, fish, beef, pork, poultry (especially chicken), etc. to the fiber assembly and culturing the cells. When using the fiber assembly as a scaffold for cultured meat, an adhesion improver that improves the adhesiveness of the cells may be added to the fiber assembly. The fiber assembly can also be used for uses other than those described above, such as chemical products and pharmaceuticals.

[0131] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0132] [Fiber Preparation] First, distilled water was added to a disposable cup and stirred using a homogenizer (T18, manufactured by IKA Corporation). The amount of distilled water added was adjusted so that the total weight of the materials added to the cup was 100 parts by weight. Next, 5.0 parts by weight of soy protein (Fujipro 748, manufactured by Fuji Oil Co., Ltd.) and 1.5 parts by weight of powdered sodium alginate (Kimica Algin I-1G, manufactured by Kimica Co., Ltd.) were added to the cup in small amounts in this order and dissolved in water to prevent lumps. Furthermore, 2 parts by weight of a 5 wt% aqueous sodium hydroxide solution was added per 100 parts by weight of the total weight of the materials added to the cup. This mixture was stirred and degassed using a THINKY MIXER (ARV-310, manufactured by Thinky Corporation) at a rotation speed of 2000 rpm, a pressure of 0.6 kPa, and an operating time of 5 minutes. This resulted in a mixture containing non-animal protein, alginate (a monovalent metal salt of alginic acid), and an alkali compound. The sodium hydroxide content in the mixed liquid was 1000 wtppm.

[0133] Next, fibers were produced using the above-described spinning apparatus 100 by the following method. First, a discharge device equipped with a gear pump was prepared as the discharge section of the spinning apparatus. A multi-hole nozzle was used as the nozzle of the discharge section. The multi-hole nozzle had 50 discharge ports with a diameter of 0.2 mm. Next, the mixed liquid was poured into the storage section of the discharge section, and the mixed liquid was discharged from the nozzle. The discharge rate of the mixed liquid from the nozzle was set to 21 mL / min. After confirming that the mixed liquid had been discharged from the nozzle, the nozzle was immersed in the coagulation liquid stored in the coagulation section. The coagulation liquid was an aqueous solution containing calcium chloride (manufactured by Canada Pharmaceutical Industries) as a coagulant and citric acid (manufactured by Kenei Pharmaceutical Co., Ltd.) as an acid compound. The calcium chloride content of the coagulation liquid was 1 wt %, and the citric acid content was 2 wt %.

[0134] The discharged material (liquid mixture) from the nozzle solidified upon contact with the coagulation liquid. This resulted in the formation of a fiber. The fiber was grasped by hand and set on a bobbin (made of silicon, diameter 7.5 cm) in the winding section. The bobbin was then driven to wind the fiber. At this time, the winding speed around the bobbin was set to 21 m / min. The draw ratio of the fiber when wound around the bobbin was 1.55.

[0135] When a sufficient amount of fiber was wound, the discharge of the mixed solution from the nozzle was stopped. Next, the fiber removed from the bobbin was cut with scissors. The obtained fiber was washed with water at 25°C for several minutes. The operation of wiping excess water from the fiber using a Kimtowel was repeated three times. This resulted in a fiber containing calcium alginate. This fiber further contained soy protein and water.

[0136] Example 1 First, a dispersion of sodium metaphosphate (Kanto Chemical Co., Ltd., product number 58023-17) as a chelating agent was prepared in a small amount of water. Next, the dispersion was added to the above-mentioned fibers, and they were kneaded for 1 minute. This brought the fibers into contact with the chelating agent, and the surfaces of the fibers were sol-formed. The fibers were kneaded with the chelating agent so that the fibers were oriented. The amount of chelating agent added was adjusted so that the ratio P1 of the weight of the chelating agent added to the fibers to the weight of the fibers was 3.0 wt%.

[0137] Next, the fibers were allowed to stand with the chelating agent in contact with them. During this time, the hydrolysis of the chelating agent gradually progressed due to the water contained in the fibers. Next, a dispersion was prepared by dispersing calcium sulfate (Fujifilm Wako Pure Chemical Industries, Ltd., product number 031-00935) as compound C containing divalent metal ions in a small amount of water. Three minutes after contacting the fibers with the chelating agent, the dispersion was added to the fibers, and they were kneaded for approximately 1 minute. The kneading of the multiple fibers and compound C was performed so that the multiple fibers were oriented. The amount of compound C added was adjusted so that the ratio P2 of the weight of compound C added to the fibers to the weight of the fibers was 1.0 wt %.

[0138] After kneading the fibers with compound C, the fibers were allowed to stand overnight. While the fibers were left standing, the surfaces of the fibers gelled. As a result, the fibers in contact with each other were bonded together, and the fiber assembly of Example 1 was obtained.

[0139] (Example 2-6) A fiber assembly of Example 2-6 was obtained by the same method as Example 1, except that the amounts of the chelating agent and compound C added were changed so that the ratios P1 and P2 were the values ​​shown in Table 1. In Example 5, compound C was not added.

[0140] Comparative Example 1 A fiber assembly of Comparative Example 1 was obtained in the same manner as in Example 1, except that no chelating agent was added.

[0141] (Comparative Example 2) A fiber assembly of Comparative Example 2 was obtained using the same method as Example 1, except that konbu acid (Konbu Acid 429, manufactured by Kimika Co., Ltd.) was used as a binder instead of the chelating agent, and compound C was not added. The konbu acid contained sodium alginate and calcium sulfate as binder components. In Comparative Example 2, an aqueous solution containing konbu acid at a content of 6 wt% was added to multiple fibers. The ratio of the weight of konbu acid added to the fibers to the weight of the fibers was 1.2 wt%.

[0142] (Comparative Example 3) A fiber assembly of Comparative Example 3 was obtained by the same method as Example 1, except that a protein cross-linking enzyme, transglutaminase (Activa Supercard, manufactured by Ajinomoto Co., Inc.), was used instead of the chelating agent, and compound C was not added. In Comparative Example 3, a dispersion containing 10 wt % transglutaminase was added to multiple fibers. The ratio of the weight of transglutaminase added to the fibers to the weight of the fibers was 1.0 wt %.

[0143] [Cross-section observation] The cross section of the prepared fiber assembly was observed under a microscope. Fig. 3 is a microscope image showing the cross section of the fiber assembly of Example 2. As can be seen from Fig. 3, in the fiber assembly of Example 2, multiple fibers were bonded to each other.

[0144] As in Example 2, it was observed under a microscope that multiple fibers were bonded to each other in the fiber assemblies of Examples 1, 3-6, and Comparative Example 3. No fibers were found to be bonded to each other in the fiber assembly of Comparative Example 1. In the fiber assembly of Comparative Example 2, it was confirmed that a binder was present between the fibers.

[0145] [Content of Chelating Agent Decomposition Products] The content of chelating agent decomposition products (orthophosphate compounds, pyrophosphate compounds) of the fiber assembly of Example 1 was measured one week after production using the following method. First, approximately 0.5 g of a test piece was collected from the fiber assembly, placed in a polypropylene container, and weighed. Next, 50 mL of ultrapure water was added to the container and an extraction operation was performed at room temperature. The resulting extract was centrifuged, and the supernatant was collected. The supernatant was diluted, and the resulting diluted solution was treated with a solid-phase extraction cartridge to remove organic matter. The sample was then filtered through a membrane filter with a pore size of 0.2 μm, and the resulting filtrate was quantitatively analyzed by ion chromatography (IC). Note that in the IC analysis, the chelating agent decomposition products were in an ionized state. IC measurement conditions Measurement device: ICS-6000 manufactured by Thermo Fisher Scientific Separation column: Dionex Ion Pac AS18 (2 mm × 250 mm) Guard column: Dionex Ion Pac AG18 (2 mm × 50 mm) Removal system: ARES-500 (external mode) Detector: Electrical conductivity detector Eluent: Potassium hydroxide aqueous solution Eluent flow rate: 0.25 mL / min Sample injection volume: 25 μL

[0146] From the results of the above quantitative analysis, it was found that the fiber assembly of Example 1 had an orthophosphate compound content of 370 wtppm and a pyrophosphate compound content of 240 wtppm.

[0147] [Tear Strength] The tear strength of the prepared fiber assembly was measured using the following method. First, a plate-shaped test piece (approximately 10 mm thick) was cut from the fiber assembly. In the test piece, each of the multiple fibers extended in the thickness direction of the test piece. Two hooks (outer diameter 3.0 mm) were pierced into the test piece in the manner described above with reference to Figure 2, and the two hooks penetrated the thickness direction of the test piece. These hooks were set in a texture analyzer (TA.XTplusC Texture Analyser, manufactured by Stable Micro Systems). Specifically, one hook was fixed to a fixed part located below the test piece, and the other hook was attached to a movable part located above the test piece. Next, a tensile test was performed by pulling the other hook upward with the movable part. The tensile test was performed at a pulling speed of 2.0 mm / sec until the test piece was torn. From the results of the tensile test, a graph showing the relationship between load and time was created, and the maximum load (N) was determined from the graph. Furthermore, the maximum load (N) was divided by the thickness (mm) of the test piece to determine the tear force. In Comparative Example 1, it was difficult to cut out a plate-shaped test piece from the fiber assembly, and therefore the tear force could not be measured.

[0148] The above test was performed at least twice for each fiber assembly. Table 1 shows the average tear strength determined from the multiple tests. The standard deviation of the tear strengths in Table 1 was 0.1 or less.

[0149] The tear strength of the fiber assembly of Example 1 was further measured by the following method. First, the fiber assembly was immersed in water at 25°C for 1 hour. A plate-shaped test piece was cut out from this fiber assembly and subjected to the above-mentioned tensile test to measure the tear strength of the fiber assembly. As a result, the tear strength of the fiber assembly immersed in water was almost the same as that of the fiber assembly not immersed in water. This result shows that all of the fiber assemblies produced in the examples and comparative examples were saturated with water.

[0150]

[0151] As can be seen from Table 1, the fiber assemblies of the examples produced by the production method of this embodiment using a chelating agent had larger tear strength values ​​than the comparative examples.

[0152] (Reference Examples 1-6) As meats that could be used as imitation targets, beef shoulder loin (Reference Example 1), beef thigh (Reference Example 2), pork loin (Reference Example 3), chicken breast (Reference Example 4), and yellowfin tuna fillets (Reference Examples 5 and 6) were prepared. All of these meats were in the form of plates with a thickness of approximately 10 mm. In Reference Examples 1-5, the meat was thoroughly grilled on both sides to make it suitable for eating.

[0153] The tear strength of the prepared meat was measured in the same manner as for the fiber assembly, and the results are shown in Table 2.

[0154]

[0155] As can be seen from the results in Tables 1 and 2, the fiber assemblies of the Examples exhibited tear strengths comparable to those of the target meat. The inventors actually ate the fiber assemblies of the Examples and the target meat, and confirmed that the fiber assemblies and meat, which have similar tear strengths, have similar textures. From these results, it can be said that the fiber assemblies of the Examples are suitable for reproducing the texture of the target meat.

[0156] The fiber assembly produced by the manufacturing method of this embodiment is suitable for use as a food substitute.

Claims

1. A method for producing a fiber assembly, comprising: step A of contacting a plurality of fibers containing a divalent metal salt of alginic acid with a chelating agent; and step B of bonding at least two of the plurality of fibers to each other by decomposing the chelating agent after step A and / or mixing with a compound containing a divalent metal ion.

2. The manufacturing method according to claim 1, wherein in step A, the chelating agent forms a complex with a divalent metal ion contained in the divalent metal salt, and in step B, the complex is decomposed by decomposing the chelating agent.

3. The manufacturing method described in claim 1, wherein in step A, the surface of the fiber is sol-ified by contact with the chelating agent, and in step B, the surface of the fiber is gel-ified by decomposition of the chelating agent and / or mixing with the compound.

4. The manufacturing method according to claim 1, wherein the fibers contain water, and in step B, the chelating agent is hydrolyzed by the water contained in the fibers.

5. The method of claim 1, wherein the chelating agent comprises a condensed phosphate compound.

6. The method of claim 1, wherein the compound comprises a calcium salt.

7. The method according to claim 6, wherein the calcium salt comprises at least one selected from the group consisting of calcium sulfate, calcium citrate, calcium carbonate, calcium lactate, and calcium chloride.

8. A fiber assembly comprising: a plurality of fibers containing a divalent metal salt of alginic acid; and a decomposition product of a chelating agent, wherein at least two of the plurality of fibers are bonded to each other.

9. The fiber assembly according to claim 8, wherein the chelating agent comprises a condensed phosphoric acid compound, and the decomposition product comprises at least one selected from the group consisting of an orthophosphoric acid compound and a pyrophosphoric acid compound.

10. The fiber assembly according to claim 8, wherein the content of the decomposition products is 10 wtppm or more.

11. A fiber assembly comprising a plurality of fibers containing a divalent metal salt of alginic acid, at least two of the plurality of fibers being bonded to each other, and having a tear strength of 0.03 N / mm or more as measured by the following test. Test: A plate-shaped test piece is cut from the fiber assembly saturated with water. Two hooks (outer diameter 3.0 mm) are pierced into the test piece, and the two hooks are passed through the thickness direction of the test piece. The two hooks are pulled away from each other at a tensile speed of 2.0 mm / sec, and the test piece is torn. The maximum load (N) at this time is divided by the thickness (mm) of the test piece to determine the tearing force.

12. The fiber assembly according to claim 11, wherein the tear strength is 3.00 N / mm or less.

13. The fiber assembly according to claim 8 or 11, which is edible.

14. The fiber assembly according to claim 8 or 11, wherein the fibers further contain non-animal protein.

15. A fiber assembly according to claim 8 or 11, wherein the average fiber diameter of the plurality of fibers is 1 cm or less.