JP2017079598A - Noodle skin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noodle skin that inhibits moisture from permeating when wrapping ingredients and improves shape retention and texture.SOLUTION: The noodle skin contains cellulose nanofibers. The noodle skin inhibits moisture from permeating when wrapping ingredients in the noodle skin and can improve shape retention and texture by using chemically modified cellulose nanofibers (oxidized cellulose nanofibers or carboxymethylated cellulose nanofibers) in particular.SELECTED DRAWING: None

Description

  The present invention relates to noodle skin. More specifically, the present invention relates to a noodle skin that improves shape retention and texture when wrapped with ingredients.

  Flour, cornstarch, rice flour and other flours, water, salt and other ingredients are mixed to create a dough, then molded and heat-treated as needed. There are dumplings and water dumplings skin, grilled skin, small dragon wrap skin, wonton skin, etc. By wrapping these noodle skins with various food ingredients as ingredients, spring rolls, grilled dumplings, boiled dumplings, grilled rice Noodle skin food such as small dragon wrap and wonton.

  In these noodle skin foods, the moisture from the ingredients penetrates into the noodle skin during the heating and storage in the manufacturing process, so that the noodle skin is easily broken, and the texture of the noodle skin, the so-called glutinous feeling May decrease. In addition, one of the sales forms of noodle skin foods is store sales at convenience stores, etc., but this form is often heated for a long time by a steamer or the like, and in that case, more moisture comes out from the ingredients. In addition to being easier, water vapor permeates from the outside of the noodle skin, making the noodle skin easier to tear and lowering the texture. These are particularly prominent problems when the noodle skin is thin.

As a method for preventing this, there is generally known a method for improving water retention and oil retention of the whole ingredient by using a raw material having water retention such as starch and bread crumb for the ingredient. However, although this method can obtain a certain effect, it cannot be said to be sufficient, and there is a problem that the texture becomes sticky. In addition, it is not effective against the penetration of water vapor from the outside of the noodle skin.
As another method, various methods for suppressing the penetration of moisture into the noodle skin by kneading the oil and fat composition into the noodle skin have been proposed. Patent Documents 1, 2 and 3 propose a method of kneading a high melting point oil and fat component into the dough, Patent Document 4 proposes a method of kneading soy protein and fat and oil, and Patent Document 5 proposes a method of kneading trehalose and fat and oil. .

JP-A-3-030651 JP-A-8-289767 JP-A-8-256671 JP 2002-65192 A JP 2004-141026 A

  However, these methods cannot completely suppress the penetration of moisture into the noodle skin, and the method of Patent Document 4 has a problem that the texture becomes brittle. The method of Patent Document 5 has a texture. There was a problem of stickiness. Therefore, the present invention provides a noodle skin that is improved in shape retention and texture by suppressing moisture permeation from the inside and outside of the noodle skin when the ingredients are wrapped by including it in the noodle skin. The purpose is to do.

The present invention provides the following.
(1) A noodle skin comprising cellulose nanofibers.
(2) The noodle skin according to (1), wherein the cellulose nanofiber is a chemically modified cellulose nanofiber.
(3) The chemically modified cellulose nanofiber is an oxidized cellulose nanofiber having an amount of carboxyl groups of 0.5 mmol / g to 3.0 mmol / g with respect to the absolutely dry weight of the chemically modified cellulose nanofiber. The noodle skin according to (2), characterized in that
(4) The chemically modified cellulose nanofiber is a carboxymethylated cellulose nanofiber having a degree of carboxymethyl substitution per glucose unit of the chemically modified cellulose nanofiber of 0.01 to 0.50, The noodle skin according to (2).

  ADVANTAGE OF THE INVENTION According to this invention, when wrapping ingredients, it suppresses a water | moisture content from penetrating from the inner side and the outer side, and provides the noodle skin which improved the shape retention property and food texture of noodle skin food.

The noodle skin of the present invention will be described in detail below.
<Noodle skin and noodle skin food>
The noodle skin in the present invention is a thin plate-like skin that is made by mixing raw materials such as flour, corn starch, rice flour and the like, water, salt, etc., forming dough, and heat-treating as necessary. Specific examples include spring roll skins, grilled and boiled dumpling skins, baked leather skins, small dragon wrap skins, and wonton skins. Noodle skin food is food that is wrapped in noodle skin using food ingredients as ingredients and cooked as needed. Specifically, spring rolls, grilled dumplings, boiled dumplings, grilled rice, small dragon wraps, wontons, etc. be able to. The noodle skin of the present invention can be suitably used for all these noodle skin foods. Specifically, it is possible to provide a noodle skin with improved shape retention and texture by suppressing moisture penetration from the inside and outside of the noodle skin when the ingredients are wrapped. Among these, when the noodle skin contains a lot of water, such as boiled dumplings and wontons, the noodle skin is originally easily broken and the texture tends to be lost, but according to the present invention, Also in use, the noodle skin is not easily torn or the shape retention and texture can be maintained even if the thickness of the skin is reduced.

  The reason why the shape retention and texture of the noodle skin food are improved by the present invention is not clear, but is considered as follows. As a feature of cellulose nanofibers contained in noodle skin, the so-called thixotropic property that the viscosity gradually decreases and becomes liquid when subjected to shearing stress, and the viscosity gradually increases when stationary, is very high. This high thixotropic property is presumed to improve the shape retention and texture of the noodle skin food by having a high viscosity in the stationary state even when moisture penetrates the noodle skin.

<Cellulose nanofiber>
The noodle skin of the present invention is characterized by containing cellulose nanofibers. Cellulose nanofiber is a material produced by loosening plant fibers to the nano level, and is generally a fine fiber having an average fiber diameter of about 3 to 500 nm and an average aspect ratio of 50 or more. The average fiber diameter and average fiber length of cellulose nanofibers can be obtained by averaging the fiber diameter and fiber length obtained from the results of observing each fiber using a field emission scanning electron microscope (FE-SEM). it can. Also, the aspect ratio can be calculated by the following formula:
Aspect ratio = average fiber length / average fiber diameter

  Cellulose nanofibers can be produced by applying a strong shearing force after the cellulose raw material is left unmodified or chemically modified. In the present invention, the cellulose raw material may be unmodified or chemically modified, but is more preferably chemically modified. Cellulose nanofibers manufactured using chemically modified cellulose raw materials have a uniform fiber length and fiber diameter compared to cellulose nanofibers manufactured using unmodified cellulose raw materials. It is assumed that it is stable and exhibits a superior effect. Although the method of chemical modification is not particularly limited, for example, oxidation, etherification, phosphorylation, esterification, silane coupling, fluorination, cationization and the like can be performed. Among them, any of oxidation, carboxymethylation, and cationization using an N-oxyl compound is preferable, and carboxymethylation or oxidation is particularly preferable because of food use.

<Cellulose raw material>
In the present invention, cellulose raw materials for producing cellulose nanofibers include plants (for example, wood, bamboo, hemp, jute, kenaf, farmland residue, cloth, pulp (conifer unbleached kraft pulp (NUKP), conifer bleach). Kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), hardwood bleached kraft pulp (LBKP), softwood unbleached sulfite pulp (NUSP), softwood bleached sulfite pulp (NBSP) thermomechanical pulp (TMP), regenerated pulp , Waste paper, etc.), animals (for example, ascidians), algae, microorganisms (for example, acetic acid bacteria (Acetobacter)), microbial products and the like are known, and any of them can be used in the present invention. Is a cellulose fiber derived from a plant or a microorganism, more preferably a plant Is a cellulose fiber of come.

  The fiber diameter of the cellulose fiber raw material used in the present invention is not particularly limited, and the number average fiber diameter is 1 μm to 1 mm. What has undergone general purification is about 50 μm. For example, when a chip or the like having a size of several centimeters is refined, it is preferable to perform a mechanical treatment with a disintegrator such as a refiner or a beater to make it about 50 μm.

<Oxidation>
In the present invention, the oxidation of the cellulose raw material can be performed using a known method, and is not particularly limited, but the amount of carboxyl groups is 0.5 mmol / g with respect to the absolute dry weight of the cellulose nanofiber. It is preferable to adjust so that it may be -3.0 mmol / g.

As an example, it can be obtained by oxidizing cellulose in water using an oxidizing agent in the presence of a compound selected from the group consisting of an N-oxyl compound and a bromide, iodide or a mixture thereof. By this oxidation reaction, the primary hydroxyl group at the C6 position of the glucopyranose ring on the cellulose surface is selectively oxidized, and a cellulose fiber having an aldehyde group and a carboxyl group or a carboxylate group on the surface can be obtained. The concentration of cellulose during the reaction is not particularly limited, but is preferably 5% by mass or less.
The N-oxyl compound refers to a compound that can generate a nitroxy radical. As the N-oxyl compound, any compound can be used as long as it promotes the target oxidation reaction.

The amount of the N-oxyl compound used is not particularly limited as long as it is a catalytic amount that can oxidize cellulose as a raw material. For example, 0.01 to 10 mmol is preferable, 0.01 to 1 mmol is more preferable, and 0.05 to 0.5 mmol is more preferable with respect to 1 g of absolutely dry cellulose. Moreover, about 0.1-4 mmol / L with respect to a reaction system is good.
Bromide is a compound containing bromine, examples of which include alkali metal bromides that can dissociate and ionize in water. Further, an iodide is a compound containing iodine, and examples thereof include alkali metal iodide. The amount of bromide or iodide used can be selected as long as the oxidation reaction can be promoted. The total amount of bromide and iodide is, for example, preferably 0.1 to 100 mmol, more preferably 0.1 to 10 mmol, and still more preferably 0.5 to 5 mmol with respect to 1 g of absolutely dry cellulose.
As the oxidizing agent, known ones can be used, and for example, halogen, hypohalous acid, halous acid, perhalogen acid or salts thereof, halogen oxide, peroxide and the like can be used. Of these, sodium hypochlorite is preferable because it is inexpensive and has a low environmental impact. The appropriate amount of the oxidizing agent used is, for example, preferably 0.5 to 500 mmol, more preferably 0.5 to 50 mmol, further preferably 1 to 25 mmol, and most preferably 3 to 10 mmol with respect to 1 g of absolutely dry cellulose. . For example, 1-40 mol is preferable with respect to 1 mol of N-oxyl compounds.

The cellulose oxidation process allows the reaction to proceed efficiently even under relatively mild conditions. Therefore, the reaction temperature is preferably 4 to 40 ° C, and may be room temperature of about 15 to 30 ° C. As the reaction proceeds, a carboxyl group is generated in the cellulose, so that the pH of the reaction solution is reduced. In order to advance the oxidation reaction efficiently, an alkaline solution such as an aqueous sodium hydroxide solution is added to maintain the pH of the reaction solution at about 8 to 12, preferably about 10 to 11. The reaction medium is preferably water because it is easy to handle and hardly causes side reactions.
The reaction time in the oxidation reaction can be appropriately set according to the degree of progress of oxidation, and is usually 0.5 to 6 hours, for example, about 0.5 to 4 hours.
The oxidation reaction may be performed in two stages. For example, by oxidizing the oxidized cellulose obtained by filtration after the completion of the first-stage reaction again under the same or different reaction conditions, the efficiency is not affected by the reaction inhibition by the salt generated as a by-product in the first-stage reaction. Can be oxidized well.

  Another example of the carboxylation (oxidation) method is a method of oxidizing by contacting a gas containing ozone and a cellulose raw material. By this oxidation reaction, at least the hydroxyl groups at the 2nd and 6th positions of the glucopyranose ring are oxidized and the cellulose chain is decomposed. The ozone concentration in the gas containing ozone is preferably 50 to 250 g / m 3, and more preferably 50 to 220 g / m 3. The amount of ozone added to the cellulose raw material is preferably 0.1 to 30 parts by mass, and more preferably 5 to 30 parts by mass when the solid content of the cellulose raw material is 100 parts by mass. The ozone treatment temperature is preferably 0 to 50 ° C, and more preferably 20 to 50 ° C. The ozone treatment time is not particularly limited, but is about 1 to 360 minutes, and preferably about 30 to 360 minutes. When the conditions for the ozone treatment are within these ranges, the cellulose can be prevented from being excessively oxidized and decomposed, and the yield of oxidized cellulose is improved. After the ozone treatment, an additional oxidation treatment may be performed using an oxidizing agent. The oxidizing agent used for the additional oxidation treatment is not particularly limited, and examples thereof include chlorine compounds such as chlorine dioxide and sodium chlorite, oxygen, hydrogen peroxide, persulfuric acid, and peracetic acid. For example, these oxidizing agents can be dissolved in a polar organic solvent such as water or alcohol to prepare an oxidizing agent solution, and a cellulose raw material can be immersed in the solution for additional oxidation treatment.

The amount of the carboxyl group, carboxylate group, and aldehyde group of the cellulose fiber can be adjusted by controlling the amount of the oxidizing agent added and the reaction time.
The method for measuring the amount of carboxyl groups is, for example, preparing 60 ml of a 0.5 mass% slurry (aqueous dispersion) of oxidized cellulose, adding 0.1 M hydrochloric acid aqueous solution to pH 2.5, and then adding 0.05 N sodium hydroxide. The electrical conductivity was measured by dropping the aqueous solution until the pH reached 11, and the amount was calculated from the amount of sodium hydroxide (a) consumed in the neutralization step of the weak acid where the change in electrical conductivity was slow, using the following formula: can do:
Carboxyl group amount [mmol / g oxidized cellulose or cellulose nanofiber] = a [ml] × 0.05 / oxidized cellulose mass [g].

<Carboxymethylation>
In the present invention, the carboxymethylation of the cellulose raw material can be carried out using a known method and is not particularly limited. However, the degree of carboxymethyl group substitution per anhydroglucose unit of cellulose is 0.01-0. It is preferable to adjust to 50. As an example, the following production method can be mentioned, but it may be synthesized by a conventionally known method or a commercially available product may be used. Cellulose is used as the starting material, and water and / or lower alcohol 3 to 20 times by weight in the solvent, specifically methanol, ethanol, N-propyl alcohol, isopropyl alcohol, N-butanol, isobutanol, tertiary butanol, etc. Or a mixed medium of two or more. The mixing ratio of the lower alcohol is 60 to 95% by weight. As the mercerizing agent, 0.5 to 20 times moles of alkali metal hydroxide, specifically sodium hydroxide or potassium hydroxide is used per anhydroglucose residue of the bottoming material. A bottoming raw material, a solvent, and a mercerizing agent are mixed and subjected to mercerization treatment at a reaction temperature of 0 to 70 ° C., preferably 10 to 60 ° C., and a reaction time of 15 minutes to 8 hours, preferably 30 minutes to 7 hours. Thereafter, a carboxymethylating agent is added in an amount of 0.05 to 10.0 times mol per glucose residue, a reaction temperature of 30 to 90 ° C., preferably 40 to 80 ° C., and a reaction time of 30 minutes to 10 hours, preferably 1 hour. Perform etherification reaction for ~ 4 hours.

As a measuring method of the carboxymethyl substitution degree per glucose unit, it can obtain by the following method, for example. That is, 1) About 2.0 g of carboxymethylated cellulose fiber (absolutely dry) is precisely weighed and put into a 300 mL conical stoppered Erlenmeyer flask. 2) Add 100 mL of a solution of 100 mL of special concentrated nitric acid to 1000 mL of nitric acid methanol and shake for 3 hours to convert the carboxymethyl cellulose salt (CM cellulose) into hydrogenated CM cellulose. 3) Weigh accurately 1.5 to 2.0 g of hydrogenated CM-modified cellulose (absolutely dry) and put into a 300 mL conical flask with a stopper. 4) Wet the hydrogenated CM cellulose with 15 mL of 80% methanol, add 100 mL of 0.1N NaOH, and shake at room temperature for 3 hours. 5) Back titrate excess NaOH with 0.1 N H2SO4 using phenolphthalein as indicator. 6) The degree of carboxymethyl substitution (DS) is calculated by the following formula:
A = [(100 × F ′ − (0.1N H 2 SO 4) (mL) × F) × 0.1] / (absolute dry mass of hydrogenated CM-modified cellulose (g))
DS = 0.162 × A / (1−0.058 × A)
A: 1N NaOH amount (mL) required for neutralizing 1 g of hydrogenated CM-modified cellulose
F ′: 0.1N H 2 SO 4 factor F: 0.1 N NaOH factor

<Cationization>
In the present invention, the cationization of the cellulose raw material can be performed using a known method, and for example, ammonium, phosphonium, sulfonium, or a group having ammonium, phosphonium or sulfonium can be contained in the cellulose molecule by cationization. A group containing ammonium is preferred, and a group containing quaternary ammonium is particularly preferred. The specific cationization method is not particularly limited, but as an example, cationization of cellulose raw material such as glycidyltrimethylammonium chloride, 3-chloro-2hydroxypropyltrialkylammonium hydride or its halohydrin type Cation having group containing quaternary ammonium by reacting agent and catalyst alkali metal hydroxide (sodium hydroxide, potassium hydroxide, etc.) in the presence of water and / or alcohol having 1 to 4 carbon atoms Modified cellulose can be obtained. In this method, the cation substitution degree per glucose unit of the cation-modified cellulose obtained is controlled by the amount of the cationizing agent to be reacted, the composition ratio of water and / or alcohol having 1 to 4 carbon atoms. Can be adjusted. The degree of substitution herein refers to the number of substituents introduced per unit structure (glucopyranose ring) constituting cellulose. In other words, it is defined as “a value obtained by dividing the number of moles of the introduced substituent by the total number of moles of hydroxyl groups of the glucopyranose ring”. Since pure cellulose has three substitutable hydroxyl groups per unit structure (glucopyranose ring), the theoretical maximum value of the degree of substitution of the cellulose fiber of the present invention is 3 (minimum value is 0).

In the present invention, the degree of cation substitution per glucose unit of cationized cellulose is preferably 0.01 to 0.40. By introducing a cationic substituent into cellulose, the celluloses repel each other electrically. For this reason, the cellulose which introduce | transduced the cation substituent can be nano-defibrated easily. In addition, when the cation substitution degree per glucose unit is smaller than 0.01, nano-defibration cannot be sufficiently performed. On the other hand, if the degree of cation substitution per glucose unit is larger than 0.40, the fiber form cannot be maintained because it swells or dissolves and may not be obtained as a nanofiber.
The degree of cation substitution per glucose unit can be calculated from the following equation by measuring the nitrogen content with a total nitrogen analyzer TN-10 (Mitsubishi Chemical) after drying the sample (cation-modified cellulose). . The degree of substitution referred to here represents the average value of the number of moles of substituents per mole of anhydroglucose unit.

Degree of cation substitution = (162 × N) / (1-151.6 × N)
N: Nitrogen content

<Defibration>
In the present invention, an apparatus for defibrating is not particularly limited, but a strong shearing force is applied to the aqueous dispersion using an apparatus such as a high-speed rotation type, a colloid mill type, a high pressure type, a roll mill type, or an ultrasonic type. Is preferred. In particular, for efficient defibration, it is preferable to use a wet high-pressure or ultrahigh-pressure homogenizer that can apply a pressure of 50 MPa or more to the aqueous dispersion and can apply a strong shearing force. The pressure is more preferably 100 MPa or more, and further preferably 140 MPa or more. In addition, prior to defibration / dispersion treatment with a high-pressure homogenizer, the cellulose nanofibers may be pretreated using a known mixing, stirring, emulsifying, and dispersing device such as a high-speed shear mixer as necessary. Is also possible.

  In the case of defibration by the above treatment, the solid content concentration as the cellulose fiber raw material is 0.1% by weight or more, preferably 0.2% by weight or more, particularly 0.3% by weight or more, and 10% by weight or less, particularly 6%. It is preferable that it is below wt%. When the solid content concentration is too low, the amount of liquid is too large with respect to the amount of the cellulose fiber raw material to be processed, resulting in poor efficiency, and when the solid content concentration is too high, the fluidity is deteriorated.

In the present invention, the mode of the cellulose nanofibers to be contained in the noodle skin is not particularly limited, and may be a dispersion of cellulose nanofibers, a dry solid of cellulose nanofibers, or a wet solid that is an intermediate state thereof. There may be. In addition, in this invention, the dry solid substance of a cellulose nanofiber means what dehydrated and dried the dispersion liquid containing a cellulose nanofiber to 12% or less of moisture content.
Examples of dry solids of cellulose nanofibers include those obtained by drying a dispersion of cellulose nanofibers, or those obtained by drying a mixed liquid of cellulose nanofibers and a water-soluble polymer. The latter is preferable in terms of redispersibility. Examples of the water-soluble polymer include cellulose derivatives (carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, ethylcellulose), xanthan gum, xyloglucan, dextrin, dextran, carrageenan, locust bean gum, alginic acid, alginate, pullulan, starch, and hard starch. , Scrap flour, Positive starch, Phosphorylated starch, Corn starch, Gum arabic, Locust bean gum, Gellan gum, Gellan gum, Polydextrose, Pectin, Chitin, Water-soluble chitin, Chitosan, Casein, Albumin, Soy protein lysate, Peptone, Polyvinyl alcohol , Polyacrylamide, sodium polyacrylate, polyvinylpyrrolidone, polyvinyl acetate, polyamino acid, polylactic acid, polymalic acid, polyglyce Latex, rosin sizing agent, petroleum resin sizing agent, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide / polyamine resin, polyethyleneimine, polyamine, plant gum, polyethylene oxide, hydrophilic cross-linked polymer, polyacrylic Refers to acid salts, starch polyacrylic acid copolymers, tamarind gum, gellan gum, pectin, guar gum and colloidal silica and mixtures of one or more thereof. Among these, it is preferable from a compatible point to use carboxymethylcellulose and its salt.

  The dry solid of the cellulose nanofiber is dehydrated and dried after adjusting the pH of the cellulose nanofiber aqueous dispersion or the mixture containing the cellulose nanofiber dispersion and the water-soluble polymer to 9-11. It is preferable from the viewpoint of redispersibility. When the water-soluble polymer is blended in the cellulose nanofiber dispersion, the amount of the water-soluble polymer is preferably 5 to 50% by weight based on the absolutely dry solid content of the cellulose nanofiber. If it is less than 5% by weight, the effect of sufficient redispersibility is not exhibited. On the other hand, when it exceeds 50% by weight, problems such as viscosity characteristics and dispersion stability, which are characteristic of cellulose nanofiber, occur.

  As the dehydration / drying method of the cellulose nanofiber dispersion or the mixture containing the cellulose nanofiber dispersion and the water-soluble polymer, any conventionally known method may be used, for example, spray drying, pressing, air drying, hot air drying, And vacuum drying. Examples of the drying apparatus specifically used in the method of the present invention are as follows. That is, continuous tunnel dryer, band dryer, vertical dryer, vertical turbo dryer, multi-stage disk dryer, aeration dryer, rotary dryer, air dryer, spray dryer dryer, spray dryer , Cylindrical dryers, drum dryers, screw conveyor dryers, rotary dryers with heating tubes, vibration transport dryers, batch-type box dryers, aeration dryers, vacuum box dryers, stirring dryers, etc. These drying apparatuses can be used alone or in combination of two or more. Among these, it is preferable to use a drum drying apparatus from the viewpoint of energy efficiency because the heat energy is uniformly supplied directly to an object to be dried. The drum drying apparatus is also preferable in that it can immediately collect a dried product without applying heat more than necessary.

  The dry solid can be crushed and classified to obtain the noodle skin of the present invention. In particular, dry pulverization or wet pulverization is preferable because a more refined additive can be obtained. Examples of the apparatus used in the dry pulverization include impact mills such as a hammer mill and a pin mill, medium mills such as a ball mill and a tower mill, and jet mills. Examples of the apparatus used in the wet pulverization include apparatuses such as a homogenizer, a mass collider, and a pearl mill.

<Addition to noodle skin>
In the present invention, the amount of cellulose nanofiber added to the noodle skin is such that the absolute dry weight of the cellulose nanofiber in the noodle skin is 0.05% by weight or more, preferably 0.1% based on the total absolute dry weight of the noodle skin. It is preferable that it is weight% or more. If the content is less than 0.05%, sufficient effects are not exhibited.

  Hereinafter, although an example is given and the present invention is explained still in detail, the present invention is not limited to these.

<Manufacture of oxidized cellulose nanofiber>
Add 500 g of bleached unbeaten kraft pulp (whiteness 85%) derived from coniferous trees (absolutely dry) to 500 ml of an aqueous solution in which 780 mg of TEMPO (Sigma Aldrich) and 75.5 g of sodium bromide are dissolved, until the pulp is uniformly dispersed Stir. An aqueous sodium hypochlorite solution was added to the reaction system to 6.0 mmol / g to initiate the oxidation reaction. During the reaction, the pH in the system was lowered, but a 3M sodium hydroxide aqueous solution was sequentially added to adjust the pH to 10. The reaction was terminated when sodium hypochlorite was consumed and the pH in the system no longer changed. The reaction mixture was filtered through a glass filter to separate the pulp, and the pulp was sufficiently washed with water to obtain oxidized pulp (carboxylated cellulose). The pulp yield at this time was 90%, the time required for the oxidation reaction was 90 minutes, and the amount of carboxyl groups was 1.6 mmol / g.

  The oxidized pulp obtained in the above step was adjusted to 1.0% (w / v) with water and treated three times with an ultrahigh pressure homogenizer (20 ° C., 150 MPa) to obtain a cellulose nanofiber dispersion. The obtained fiber had an average fiber diameter of 3 nm and an aspect ratio of 250.

<Production of carboxymethylated cellulose nanofiber>
In a stirrer capable of mixing pulp, 200 g dry pulp (NBKP (conifer bleached kraft pulp), manufactured by Nippon Paper Industries Co., Ltd.) and 111 g sodium hydroxide dry mass are added, and the pulp solid content is 20% (w / V) was added water. Thereafter, after stirring at 30 ° C. for 30 minutes, 216 g of sodium monochloroacetate (in terms of active ingredient) was added. After stirring for 30 minutes, the temperature was raised to 70 ° C. and stirred for 1 hour. Thereafter, the reaction product was taken out, neutralized and washed to obtain a carboxymethylated pulp having a carboxymethyl substitution degree of 0.25 per glucose unit. Thereafter, the carboxymethylated pulp was made 1% solids with water, and fibrillated by treating it with a high-pressure homogenizer 5 times at 20 ° C. and 150 MPa to obtain carboxymethylated cellulose fibers. The obtained fiber had an average fiber diameter of 15 nm and an aspect ratio of 50.

<Manufacture of cationized cellulose nanofiber>
Add pulp (NBKP, manufactured by Nippon Paper Industries Co., Ltd.) in dry weight of 200g and sodium hydroxide in dry weight of 24g to pulper that can stir the pulp, and add water so that the pulp solid concentration is 15%. It was. Then, after stirring for 30 minutes at 30 ° C., the temperature was raised to 70 ° C., and 200 g (in terms of active ingredient) of 3-chloro-2-hydroxypropyltrimethylammonium chloride was added as a cationizing agent. After reacting for 1 hour, the reaction product was taken out, neutralized and washed to obtain cation-modified cellulose having a cation substitution degree of 0.05 per glucose unit. Thereafter, the cation-modified pulp was treated at a solid concentration of 1% and treated twice with a high-pressure homogenizer at 20 ° C. and a pressure of 140 MPa. The obtained fiber had an average fiber diameter of 25 nm and an aspect ratio of 50.

<Example 1>
Carboxymethylcellulose (trade name: F350HC-4, manufactured by Nippon Paper Industries Co., Ltd.) is added to 0.7% by weight aqueous suspension of the above oxidized cellulose nanofibers with respect to the cellulose nanofibers, and a TK homomixer is added. The mixture was stirred at (12,000 rpm) for 60 minutes. To this aqueous suspension, 0.5% aqueous sodium hydroxide solution was added to adjust the pH to 9, and then the vapor pressure was 0.5 MPa. G, and dried with a drum dryer D0405 (manufactured by Katsuragi Industry Co., Ltd.) with a drum rotation speed of 2 rpm, to obtain a mixed dry solid of cellulose nanofibers and carboxymethyl cellulose having a water content of 5% by weight. The dried solid was pulverized by a dry mill to obtain cellulose nanofiber for addition in the present invention.

Subsequently, 280 g of strong powder, 120 g of weak powder, and 2.0 g of the above cellulose nanofiber for addition were mixed, and further mixed with 4.8 g of vegetable oil and fat and 148 g of water. After kneading, the dough was put together and allowed to sleep for about 30 minutes at room temperature. After laying down, rolling was repeated, and when the final thickness reached 0.6 mm, it was hollowed out, dusted and stored in a refrigerator to obtain a dumpling skin as noodle skin. The content of the cellulose nanofiber for addition of the present invention in the noodle skin is 0.55% by weight with respect to the total dry weight of the noodle skin, and the absolute dry weight of the cellulose nanofiber in the cellulose nanofiber for addition is And 0.5% by weight based on the total dry weight of the noodle skin.
Subsequently, a gelatin soup was prepared according to the formulation shown in Table 1. This gelatin soup was stored in a refrigerator for a day to form a jelly, and the raw materials containing the gelatin soup shown in Table 2 were kneaded to be uniform to obtain dumpling cake.

Next, for 13 pieces of gyoza skin, wrap with 13g of rice cake, steam using a convection oven at 100 ° C for 10 minutes, and after removing the rough heat, baked and baked. A grilled dumpling with gelatin soup was obtained.
The obtained grilled dumplings with gelatin soup were tested for shape retention and texture by the following method.

<Shape retention>
The appearance when the baked surface was left to stand was visually evaluated according to the following criteria.
○: It is almost the same as the shape before steaming and has a volume feeling.
Δ: There is no volume, it spreads sideways, and there is no volume feeling.
X: The skin is torn and the original shape is not retained.

<Food texture>
Ten panelists sampled the dumplings and evaluated the texture (moist feeling) by the following 5-point method, and the average score was taken as the evaluation score.
5 points: The skin is very sticky and has a very good texture. 3 points: The skin is somewhat sticky and has almost a good texture.
1 point: The skin is crunchy and the texture is poor.

<Example 2>
The same procedure as in Example 1 was performed except that the cellulose nanofiber in the cellulose nanofiber for addition in Example 1 was changed to the carboxymethylated cellulose nanofiber produced by the above method.

<Comparative Example 1>
The same operation as in Example 1 was performed except that the cellulose nanofiber for addition was not used in Example 1.

  As is apparent from the results in Table 3, in Examples 1 and 2 containing cellulose nanofibers, both shape retention and texture are good compared to Comparative Example 1 containing no cellulose nanofibers. I understand.

Claims (4)

A noodle skin comprising cellulose nanofibers. The noodle skin according to claim 1, wherein the cellulose nanofibers are chemically modified cellulose nanofibers. The chemically modified cellulose nanofiber is an oxidized cellulose nanofiber having an amount of carboxyl groups of 0.5 mmol / g to 3.0 mmol / g with respect to the absolutely dry weight of the chemically modified cellulose nanofiber. The noodle skin according to claim 2. 3. The chemically modified cellulose nanofiber according to claim 2, wherein the chemically modified cellulose nanofiber is a carboxymethylated cellulose nanofiber having a degree of carboxymethyl substitution per glucose unit of 0.01 to 0.50. Noodle skin as described.