Dried noodles

Abstract

To provide such a dry noodle that, even after boiling the dry noodle in hot water and keeping it in a refrigerator, decrease of texture, such as decrease of stiffness of the noodle does not occur.SOLUTION: A dry noodle is allowed to contain cellulose nanofibers (preferably, carboxymethylated cellulose nanofibers having a carboxymethyl substitution degree in the range of 0.01-0.50).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to dried noodles such as udon, soba, somen, and hiyamugi. [Background technology]

[0002] Noodles are a popular staple food, and among them, dried noodles and instant noodles are popular because they are dry and therefore have excellent long-term storage properties and are easy to prepare.

[0003] In general, dried noodles and instant noodles are manufactured as follows. Wheat flour and other ingredients are usually used as the main ingredient, and this is mixed with water, salt, alkaline water, and other ingredients to create noodle dough, which is then rolled and cut out to produce fresh noodle strands. The cut fresh noodle strands are generally steamed with saturated steam, and then seasoned as needed, cut to a specified length, measured out as one serving, and dried with hot air or other means to produce dried noodles or instant noodles.

[0004] Dried noodles are boiled in hot water before eating, while somen and hiyamugi are boiled, washed in cold water, and then cooled before eating.

[0005] Patent Document 1 describes the addition of water-insoluble cellulose to dry noodles so that they do not lose texture when boiled, frozen, and then thawed in water. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-120617 Summary of the Invention [Problem to be solved by the invention]

[0007] However, dried noodles are sometimes boiled in hot water, stored in a refrigerator for 1-2 days, and then sold in stores, but such noodles have the problem of a deterioration in texture, such as a loss of firmness.

[0008] Therefore, the present invention provides dried noodles that do not lose texture, such as firmness, even when the dried noodles are boiled in hot water and then stored in a refrigerator. [Means for solving the problem]

[0009] (1) Dried noodles containing cellulose nanofiber and cereal flour. (2) Dried noodles according to (1), wherein the cellulose nanofibers are anion-modified cellulose nanofibers. (3) Dried noodles according to (1) or (2), wherein the anion-modified cellulose nanofibers are cellulose nanofibers having a carboxyl group or cellulose nanofibers having a carboxyalkyl group. (4) Dried noodles according to (3), wherein the anion-modified cellulose nanofibers are carboxymethylated cellulose nanofibers having a degree of carboxymethyl substitution in the range of 0.01 to 0.50. (5) The dried noodles according to any one of (1) to (4), further containing carboxymethyl cellulose. (6) The dried noodles according to any one of (1) to (5), which are one type selected from the group consisting of udon, soba, somen, hiyamugi, Chinese noodles, yakisoba, macaroni, spaghetti, pasta, Korean hiyashi noodles, kudzu noodles, glass noodles, rice vermicelli, gyoza wrappers, shumai wrappers, and wontons. (7) The dried noodles according to any one of (1) to (6), characterized in that the dried noodles are instant noodles. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide dried noodles that do not lose texture, such as firmness, even when the dried noodles are boiled in hot water and then stored in a refrigerator. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below. In the present invention, "to" includes the extreme values. That is, "X to Y" includes the values X and Y at both ends.

[0012] The dried noodles of the present invention contain grain flour, cellulose nanofibers, and, as necessary, other ingredients. The cellulose nanofibers contained in the dried noodles are water-insoluble and therefore do not dissolve or deform when the dried noodles are rehydrated in hot water. This is thought to prevent the firmness of the noodles from decreasing even when the noodles are stored in a freezer after boiling.

[0013] The dried noodles in the present invention are foods generally referred to as dried noodles, regardless of their form or type, which are produced using cereal flour as the main ingredient and are dried to a moisture content of 15% or less. Specific examples include udon, soba, Chinese noodles, hiyamugi (cold wheat noodles), somen (thin noodles), Chinese noodles, yakisoba (fried noodles), macaroni, spaghetti, Korean hiyashi noodles, kudzu noodles, glass noodles, rice vermicelli, gyoza (dumpling) wrappers, shumai (steamed dumpling) wrappers, wontons, etc. Examples of the form of the dried noodles include dried noodles and instant noodles. Dried noodles are an example of noodles in which the effects of the present invention can be particularly effectively obtained.

[0014] The main raw materials for dried noodles include wheat flour (hard flour, semi-hard flour, medium-strength flour, soft flour, durum wheat flour, whole wheat flour, etc.), rice flour, buckwheat flour, and other cereal flours. In addition, if necessary, unprocessed starches such as potato starch, sweet potato starch, tapioca starch, corn starch, waxy corn starch, rice starch, and mung bean starch, as well as processed starches produced by etherifying, esterifying, oxidizing, bleaching, crosslinking, pregelatinizing, or other processes, either alone or in combination, can be used. Salt and brine can also be added as additives. In addition to these, thickening stabilizers such as phosphates, alginic acid, caprobean gum, guar gum, tamarind seed gum, pectin, xanthan gum, carrageenan, and curdlan, emulsifiers, oils and fats, egg whites, milk proteins, coloring agents, antioxidants, wheat proteins, and other physiologically active ingredients such as vitamins, calcium, iron, and other seasonings can also be used as desired.

[0015] (Cellulose nanofiber) In the present invention, cellulose nanofibers (hereinafter sometimes referred to as CNF) are fine fibers with a fiber width of about 1 to 500 nm, which are made by pulp, a cellulose-based raw material, being refined to the nanometer level. The average fiber diameter and average fiber length of cellulose nanofibers can be obtained by averaging the fiber diameters and fiber lengths obtained from the observation of each fiber using an atomic force microscope (AFM) or a transmission electron microscope (TEM). The average aspect ratio of cellulose nanofibers is usually 50 or more. There is no particular upper limit, but it is usually 1000 or less. The average aspect ratio can be calculated using the following formula: Aspect ratio = average fiber length / average fiber diameter

[0016] Cellulose nanofibers are obtained by applying mechanical force to pulp to reduce its size, and can be obtained by defibrating unmodified cellulose or modified cellulose such as carboxylated cellulose (also called oxidized cellulose), carboxymethylated cellulose, anionically modified cellulose such as cellulose with introduced phosphate ester groups, or cationized cellulose. The average fiber length and average fiber diameter of the fine fibers can be adjusted by oxidation treatment and defibration treatment. In the present invention, it is preferable to use carboxymethylated (CM) cellulose nanofibers obtained by defibrating carboxymethylated cellulose obtained by carboxymethylation treatment.

[0017] (cellulose raw material) Examples of cellulose raw materials for producing the cellulose nanofibers used in the present invention include those derived from plant materials (e.g., wood, bamboo, hemp, jute, kenaf, agricultural waste, cloth, and pulp), animal materials (e.g., sea squirts), algae, and microorganisms (e.g., acetic acid bacteria (Acetobacter)). Pulp includes unbleached softwood kraft pulp (NUKP), bleached softwood kraft pulp (NBKP), unbleached hardwood kraft pulp (LUKP), bleached hardwood kraft pulp (LBKP), unbleached softwood sulfite pulp (NUSP), bleached softwood sulfite pulp (NBSP), thermomechanical pulp (TMP), recycled pulp, and waste paper. While all of these can be used, cellulose fibers derived from plants or microorganisms are preferred, and plant-derived cellulose fibers are more preferred.

[0018] (carboxymethylation) When carboxymethylated cellulose nanofibers are used in the present invention, the carboxymethylated cellulose may be obtained by carboxymethylating the above-mentioned cellulose raw material using a known method, or a commercially available product may be used. In either case, the degree of carboxymethyl substitution per anhydroglucose unit of the cellulose is preferably 0.01 to 0.50. An example of a method for producing such carboxymethylated cellulose is as follows: Cellulose is used as the starting material, and 3 to 20 times by mass of water or a lower alcohol is used as the solvent. Specifically, water, methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, tertiary butanol, etc. can be used alone or in combination of two or more. When a mixed solvent of water and a lower alcohol is used, the lower alcohol is mixed in a ratio of 60 to 95% by mass. As the mercerizing agent, 0.5 to 20 times the molar amount of an alkali metal hydroxide, specifically sodium hydroxide or potassium hydroxide, is used per anhydroglucose residue of the starting material. The starting material, solvent, and mercerizing agent are mixed, and a mercerization treatment is carried out at a reaction temperature of 0 to 70°C, preferably 10 to 60°C, for a reaction time of 15 minutes to 8 hours, preferably 30 minutes to 7 hours. Thereafter, a carboxymethylating agent is added at 0.05 to 10.0 times the moles per glucose residue, and an etherification reaction is carried out at a reaction temperature of 30 to 90°C, preferably 40 to 80°C, for a reaction time of 30 minutes to 10 hours, preferably 1 hour to 4 hours.

[0019] <Carboxymethylated cellulose nanofiber> The carboxymethylated cellulose nanofibers of the present invention maintain at least a portion of their fibrous shape even when dispersed in water. That is, when an aqueous dispersion of the carboxymethylated cellulose nanofibers is observed under an electron microscope, a fibrous substance can be observed. Furthermore, when the carboxymethylated cellulose nanofibers are measured by X-ray diffraction, a peak of cellulose type I crystals can be observed.

[0020] <Crystallization degree of cellulose type I> The degree of crystallinity of cellulose in the carboxymethylated cellulose nanofibers used in the present invention is preferably 40% or more, more preferably 50% or more, for crystalline type I. When the degree of crystallinity of type I cellulose is as high as 40% or more, a high proportion of cellulose maintains its crystalline structure without dissolving in solvents such as water, resulting in high thixotropy and making it suitable for viscosity-adjusting applications such as thickeners. Furthermore, for example, but not limited to, when added to gel-like substances (e.g., foods, cosmetics, etc.), it has the advantage of imparting excellent shape retention. The crystallinity of cellulose can be controlled by the concentration of the mercerizing agent, the treatment temperature, and the degree of carboxymethylation. Because high concentrations of alkali are used in mercerization and carboxymethylation, type I cellulose crystals are likely to be converted to type II cellulose crystals. However, the desired crystallinity can be maintained by adjusting the degree of denaturation, such as by adjusting the amount of alkali (mercerizing agent) used. There is no particular upper limit to the degree of crystallinity of type I cellulose. In practice, the upper limit is thought to be approximately 90%.

[0021] The method for measuring the crystallinity of cellulose type I of carboxymethylated cellulose nanofibers is as follows: The sample was placed in a glass cell and measured using an X-ray diffraction measurement device (LabX XRD-6000, Shimadzu Corporation). The crystallinity was calculated using the method of Segal et al., where the diffraction intensity at 2θ = 10° to 30° in the X-ray diffraction pattern was used as the baseline, and the crystallinity was calculated using the diffraction intensity of the 002 plane at 2θ = 22.6° and the diffraction intensity of the amorphous part at 2θ = 18.5° using the following formula.

[0022] Xc = (I002c - Ia) / I002c × 100 Xc = Crystallinity of cellulose type I (%) I002c: 2θ=22.6°, diffraction intensity of the 002 plane Ia: 2θ=18.5°, diffraction intensity of the amorphous part.

[0023] The proportion of type I crystals in carboxymethylated cellulose nanofibers is usually the same as that in the carboxymethyl cellulose before being made into nanofibers.

[0024] <Carboxymethyl substitution degree> The carboxymethylated cellulose nanofibers used in the present invention preferably have a degree of carboxymethyl substitution per anhydroglucose unit of cellulose of 0.50 or less. If the degree of carboxymethyl substitution exceeds 0.50, it is believed that the cellulose will dissolve in water and will no longer be able to maintain its fibrous shape. In consideration of operability, the degree of substitution is preferably 0.01 to 0.50, more preferably 0.02 to 0.50, even more preferably 0.05 to 0.40, and even more preferably 0.10 to 0.40. By introducing carboxymethyl groups into cellulose, the cellulose molecules electrically repel each other, making it possible to defibrate the cellulose into nanofibers. However, if the degree of carboxymethyl substitution per anhydroglucose unit is less than 0.01, defibration will be insufficient, and highly transparent cellulose nanofibers may not be obtained. While it has been difficult to obtain carboxymethylated cellulose nanofibers having a cellulose type I crystallinity of 60% or more when the degree of carboxymethyl substitution is in the range of 0.20 to 0.40 using conventional aqueous methods, the present inventors have discovered that, for example, by the method described below, it is possible to produce carboxymethylated cellulose nanofibers having a carboxymethyl substitution degree of 0.20 to 0.40 and a cellulose type I crystallinity of 60% or more. The carboxymethyl substitution degree can be adjusted by controlling the amount of carboxymethylating agent added to the reaction, the amount of mercerizing agent, the composition ratio of water to organic solvent, etc.

[0025] In the present invention, anhydroglucose unit refers to each anhydroglucose (glucose residue) that constitutes cellulose. The degree of carboxymethyl substitution (also referred to as the degree of etherification) refers to the proportion of hydroxyl groups in the glucose residues that constitute cellulose that have been substituted with carboxymethyl ether groups (the number of carboxymethyl ether groups per glucose residue). The degree of carboxymethyl substitution is sometimes abbreviated as DS.

[0026] The degree of carboxymethyl substitution is measured as follows: Weigh out approximately 2.0 g of sample and place it in a 300 mL Erlenmeyer flask with a stopper. Add 100 mL of a solution of 1000 mL of nitric acid methanol and 100 mL of special-grade concentrated nitric acid, and shake for 3 hours to convert the carboxymethylated cellulose nanofiber salt (CMC) into H-CMC (hydrogen-type carboxymethylated cellulose nanofiber). Weigh out 1.5 to 2.0 g of the bone-dry H-CMC and place it in a 300 mL Erlenmeyer flask with a stopper. Wet the H-CMC with 15 mL of 80% methanol, add 100 mL of 0.1 N NaOH, and shake for 3 hours at room temperature. Using phenolphthalein as an indicator, back-titrate the excess NaOH with 0.1 N H2SO4, and calculate the degree of carboxymethyl substitution (DS value) using the following formula: A=[(100×F'-0.1N-H2SO4(mL)×F)×0.1] / (H-CMC Absolute dry mass (g) Carboxymethyl substitution degree = 0.162 x A / (1 - 0.058 x A) F': Factor of 0.1N-H2SO4 F: Factor of 0.1N NaOH.

[0027] The degree of carboxymethyl substitution in the carboxymethylated cellulose nanofibers is usually the same as the degree of carboxymethyl substitution in the carboxymethylated cellulose before being made into nanofibers.

[0028] <Fiber diameter, aspect ratio> The carboxymethyl cellulose nanofibers used in the present invention have a nanoscale fiber diameter, preferably 3 nm to 500 nm, more preferably 3 nm to 150 nm, even more preferably 3 nm to 20 nm, even more preferably 5 nm to 19 nm, and even more preferably 5 nm to 15 nm.

[0029] The aspect ratio of the carboxymethylated cellulose nanofiber is not particularly limited, but is preferably 350 or less, more preferably 300 or less, even more preferably 200 or less, even more preferably 120 or less, even more preferably 100 or less, and even more preferably 80 or less. An aspect ratio of 350 or less means that the fibers are not excessively long, reducing entanglement between fibers and reducing the formation of cellulose nanofiber clumps, making it suitable for use as an additive. Furthermore, its high fluidity makes it easy to use even at high concentrations, offering the advantage of being easy to use in applications requiring a high solids content. The lower limit of the aspect ratio is not particularly limited, but is preferably 25 or more, more preferably 30 or more. An aspect ratio of 25 or more provides the effect of improved thixotropy due to the fibrous shape. The aspect ratio of the carboxymethylated cellulose nanofiber can be controlled by the mixing ratio of solvent and water during carboxymethylation, the amount of chemicals added, and the degree of carboxymethylation. Furthermore, carboxymethylated cellulose nanofibers can be produced, for example, by the production method described below.

[0030] The average fiber diameter and average fiber length of carboxymethyl cellulose nanofibers can be measured by analyzing 200 randomly selected fibers using an atomic force microscope (AFM) if the diameter is 20 nm or less, or a field emission scanning electron microscope (FE-SEM) if the diameter is 20 nm or more, and calculating the average. The aspect ratio can be calculated using the following formula: Aspect ratio = average fiber length / average fiber diameter.

[0031] (defibration) The cellulose raw material may be defibrated either before or after the denaturation treatment. Defibration may be performed once or multiple times. In the case of multiple times, each defibration may be performed at any time.

[0032] The device used for defibration is not particularly limited, but examples include devices of high-speed rotation type, colloid mill type, high-pressure type, roll mill type, and ultrasonic type. A high-pressure or ultra-high-pressure homogenizer is preferred, and a wet high-pressure or ultra-high-pressure homogenizer is more preferred. The device is preferably capable of applying a strong shear force to the cellulose raw material or modified cellulose (usually a dispersion). The pressure that the device can apply is preferably 50 MPa or more, more preferably 100 MPa or more, and even more preferably 140 MPa or more. The device is preferably a wet high-pressure or ultra-high-pressure homogenizer that can apply the above pressure and strong shear force to the cellulose raw material or modified cellulose (usually a dispersion). This allows for efficient defibration.

[0033] When defibrating a dispersion of cellulose raw materials, the solids concentration of the cellulose raw materials in the dispersion is usually 0.1% by mass or more, preferably 0.2% by mass or more, and more preferably 0.3% by mass or more. This ensures an appropriate amount of liquid relative to the amount of cellulose fiber raw material, which is efficient. The upper limit is usually 10% by mass or less, and preferably 6% by mass or less. This allows fluidity to be maintained.

[0034] Prior to defibration (preferably with a high-pressure homogenizer) or, if necessary, dispersion treatment prior to defibration, a pretreatment may be carried out as necessary. The pretreatment may be carried out using a mixing, stirring, emulsifying, or dispersing device such as a high-speed shear mixer.

[0035] (Dry) The cellulose nanofibers used in the present invention can be used in the form of a dispersion obtained after defibration, or they can be dried and redispersed in water as needed. The drying method is not particularly limited, and known methods such as freeze drying, spray drying, tray drying, drum drying, belt drying, a method of thinly spreading the nanofibers on a glass plate or the like and drying them, fluidized bed drying, microwave drying, and heated fan-type reduced pressure drying can be used. After drying, the nanofibers can be pulverized as needed using a cutter mill, hammer mill, pin mill, jet mill, or the like. The method for redispersing the nanofibers in water is also not particularly limited, and known dispersing devices can be used.

[0036] The cellulose nanofibers used in the present invention may be in the form of a dispersion or powder, but from the viewpoint of excellent workability during the production of confectioneries, it is preferable to use them in the form of a dispersion.

[0037] In the present invention, the blending amount of cellulose nanofibers is preferably 0.01 to 5 mass %, more preferably 0.05 to 3 mass %, and even more preferably 0.1 to 2 mass %, calculated as solid content, relative to the cereal flour.

[0038] The cellulose nanofibers of the present invention may contain other components as needed. For example, when producing a powder, it is preferable to add a water-soluble polymer to the cellulose nanofiber dispersion before drying, as this improves redispersibility.

[0039] <Water-soluble polymer> Examples of water-soluble polymers include cellulose derivatives (carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, ethylcellulose), xanthan gum, xyloglucan, dextrin, dextran, carrageenan, locust bean gum, alginic acid, alginates, pullulan, starch, potato starch, arrowroot flour, corn starch, gum arabic, locust bean gum, gellan gum, polydextrose, pectin, chitin, water-soluble chitin, chitosan, casein, albumin, soy protein lysate, peptone, tamarind gum, and guar gum. Among these, cellulose derivatives are preferred in terms of their affinity with carboxymethylated cellulose nanofibers, and carboxymethylcellulose and its salts are particularly preferred. It is believed that water-soluble polymers such as carboxymethylcellulose and its salts penetrate between carboxymethylated cellulose nanofibers, increasing the distance between the nanofibers and thereby improving redispersibility.

[0040] When carboxymethyl cellulose or a salt thereof is used as the water-soluble polymer, it is preferable to use a carboxymethyl cellulose with a degree of carboxymethyl group substitution per anhydroglucose unit of 0.55 to 1.6, more preferably 0.55 to 1.1, and even more preferably 0.65 to 1.1. Furthermore, carboxymethyl cellulose with longer molecules (higher viscosity) is preferred because it is more effective in increasing the distance between nanofibers. Furthermore, the Brookfield viscosity of a 1% by mass aqueous solution of carboxymethyl cellulose at 25°C and 60 rpm is preferably 3 mPa·s to 14,000 mPa·s, more preferably 7 mPa·s to 14,000 mPa·s, and even more preferably 1,000 mPa·s to 8,000 mPa·s. Note that the "carboxymethyl cellulose or a salt thereof" referred to here as the water-soluble polymer is completely soluble in water, and is therefore distinct from the carboxymethyl cellulose nanofibers described above, the fiber shape of which can be confirmed in water.

[0041] The amount of the water-soluble polymer to be blended is preferably 5% by mass to 300% by mass, more preferably 20% by mass to 300% by mass, even more preferably 25% by mass to 200% by mass, and even more preferably 25% by mass to 60% by mass, relative to the cellulose nanofiber (bone dry solid content).

[0042] The dried noodles of the present invention can be produced using conventionally known production methods. For example, this can be done as follows. First, a noodle dough containing the ingredients contained in the dried noodles of the present invention is prepared. Fresh noodle strands of the desired shape are produced from this noodle dough using conventionally known methods. The resulting fresh noodle strands are then subjected to both a process of boiling in hot water or a steaming process, and a process of drying using hot air or deep-frying, thereby achieving final starch gelatinization. Starch gelatinization in the steaming process is minimized, that is, the starch granules are brought to a state where they are only swollen to the limit without being disintegrated by the heat of the steaming process. The noodles are then dried. The drying process can be, for example, high-temperature drying, such as hot air drying or deep-frying drying. [Example]

[0043] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0044] (Method for measuring degree of carboxymethyl substitution) 1) Accurately weigh out approximately 2.0 g of carboxymethylated cellulose fiber (bone dry) and place it in a 300 mL Erlenmeyer flask with a stopper. 2) Add 100 mL of a solution of 1000 mL of nitric acid methanol and 100 mL of special-grade concentrated nitric acid, shake for 3 hours, and convert the carboxymethyl cellulose salt (carboxymethyl cellulose) into hydrogen-type carboxymethyl cellulose. 3) Accurately weigh out 1.5 to 2.0 g of hydrogenated carboxymethyl cellulose (bone dry) and place it in a 300 mL Erlenmeyer flask with a stopper. 4) Wet the hydrogenated carboxymethyl cellulose with 15 mL of 80% methanol, add 100 mL of 0.1 N NaOH, and shake at room temperature for 3 hours. 5) Back-titrate excess NaOH with 0.1N H2SO4 using phenolphthalein as an indicator. 6) The degree of carboxymethyl substitution (DS) is calculated by the following formula: A = [(100 × F' - (0.1N H2SO4) (mL) × F) × 0.1] / (bone-dry mass of hydrogenated carboxymethyl cellulose (g)) DS=0.162×A / (1-0.058×A) A: Amount of 1N NaOH (mL) required to neutralize 1 g of hydrogenated carboxymethyl cellulose F': Factor of 0.1N H2SO4 F: Factor of 0.1N NaOH (Method for measuring average fiber diameter and aspect ratio) The average fiber diameter and average fiber length of CNF were analyzed using an atomic force microscope (AFM) for 200 randomly selected fibers. The aspect ratio was calculated using the following formula: Aspect ratio = average fiber length / average fiber diameter

[0045] [Example 1] (Preparation of carboxymethylated cellulose nanofibers) A 5-L twin-screw kneader with the rotation speed adjusted to 100 rpm was charged with 1,089 parts of isopropanol (IPA) and a solution of 31 parts of sodium hydroxide in 121 parts of water. 200 parts of hardwood pulp (LBKP, manufactured by Nippon Paper Industries Co., Ltd.) (dry mass after drying at 100°C for 60 minutes) was then added. The mixture was stirred and mixed at 30°C for 60 minutes to prepare mercerized cellulose. Further stirring was continued, and 117 parts of sodium monochloroacetate was added. After stirring at 30°C for 30 minutes, the mixture was heated to 70°C over 30 minutes and allowed to undergo a carboxymethylation reaction at 70°C for 60 minutes. The proportion of water in the reaction medium during the mercerization and carboxymethylation reactions was 10% by mass. After completion of the reaction, the mixture was neutralized, washed with 65% aqueous methanol, deliquored, dried, and pulverized to obtain a sodium salt of carboxymethylated cellulose with a carboxymethyl substitution degree of 0.27 and a crystallinity of cellulose type I of 64%. The methods for measuring the degree of carboxymethyl substitution and the crystallinity of cellulose type I are as described above. The resulting sodium salt of carboxymethyl cellulose was dispersed in water to form a 1% (w / v) aqueous dispersion. This was then processed three times in a high-pressure homogenizer at 150 MPa to obtain a dispersion of carboxymethyl cellulose nanofibers. The resulting carboxymethyl cellulose nanofibers had an average fiber diameter of 3.2 nm and an aspect ratio of 40. The obtained carboxymethylated cellulose nanofibers were dispersed in water to a solid content of 0.7% by mass, and carboxymethyl cellulose (manufactured by Nippon Paper Industries Co., Ltd., product name: F350HC-4, viscosity (1% by mass, 25°C, 60 rpm) approximately 3000 mPa·s, degree of carboxymethyl substitution approximately 0.90) was added in an amount of 40% by mass relative to the carboxymethyl cellulose nanofibers (i.e., so that the solid content of carboxymethyl cellulose was 40 parts by mass per 100 parts by mass of the solid content of the carboxymethyl cellulose nanofibers), and the mixture was stirred for 60 minutes using a TK homomixer (12,000 rpm). To this dispersion, 0.5% by mass of aqueous sodium hydroxide was added to adjust the pH to 9, and then the dispersion was applied to the drum surface of a drum dryer D0405 (manufactured by Katsuragi Kogyo Co., Ltd.) and dried at 140°C for 1 minute. The resulting dried product was scraped off and then pulverized using an impact mill at a rate of 10 kg per hour to obtain a dried pulverized product with a moisture content of 5% by mass. The pulverized product was classified using a 30 mesh to obtain a powder containing carboxymethylated cellulose nanofibers and carboxymethyl cellulose (CNF powder).

[0046] (Dried udon noodle manufacturing) 100 parts wheat flour, 1 part salt, and 1 part CNF powder obtained above were placed in a stainless steel beaker and mixed at 5000 rpm for 5 minutes using a TK homomixer to prepare udon dough. Next, the mixture was rolled out using a noodle roller and noodle strands were made according to the prescribed method. After drying to a moisture content of approximately 15%, dried udon noodles were obtained. 200 g of the dried udon noodles were boiled in 2.5 L of water for 13 minutes. Then, the noodles were drained in a colander and washed with cold water to remove the slime. The noodles were transferred to a tray, covered with plastic wrap, and stored in the refrigerator. The udon noodles were stored in the refrigerator for 0, 6, 24, and 48 hours, and then tasted. The tensile strength of each sample was measured using the following method. Tasting rating: The texture (ease of swallowing, ease of disintegration) was evaluated on a 10-point scale from excellent: 10 to poor: 1. Tensile strength measurement: Using a digital force gauge, a piece of udon was folded in half to form a ring, and a hook-shaped attachment was attached to the measuring part. The attachment was then hooked onto the ring and pulled straight up, measuring the strength at which the udon was torn in two.

[0047] [Comparative Example 1] Dry udon noodles were produced in the same manner as in Example 1, except that no CNF powder was added, and the tasting and tensile strength were measured.

[0048] The results of the taste test evaluation of the udon noodles of Example 1 and Comparative Example 1 are shown in Table 1, and the tensile strength is shown in Table 2.

[0049] [Table 1]

[0050] [Table 2]

[0051] As shown in Table 1, when the udon noodles of Example 1 were stored in a freezer after boiling, the texture deteriorated more slowly over time than the udon noodles of Comparative Example 1. Furthermore, as shown in Table 2, the tensile strength also deteriorated more slowly over time.

Claims

1. Carboxymethylated cellulose nanofibers; A dried noodle containing carboxymethyl cellulose or a salt thereof having a degree of carboxymethyl group substitution per anhydroglucose unit of 0.65 to 1.1, and cereal flour, The dried noodles contain the carboxymethyl cellulose and its salt in an amount ranging from 25 to 60% by mass relative to the cellulose nanofiber (bone dry solid content).

2. The dried noodles according to claim 1, wherein the carboxymethylated cellulose nanofibers have a degree of carboxymethyl substitution in the range of 0.01 to 0.

50.

3. The dried noodles according to any one of claims 1 to 2, wherein the dried noodles are one type selected from the group consisting of udon, buckwheat, somen, hiyamugi, Chinese noodles, yakisoba, macaroni, spaghetti, pasta, Korean hiyashi noodles, kudzu noodles, glass noodles, rice vermicelli, gyoza wrappers, shumai wrappers, and wontons.

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