JP7369379B2 - Nanofiber derived from citrus peel and its production method - Google Patents

Description

The present invention relates to citrus peel nanofibers, food or cosmetic compositions containing the nanofibers, and methods for producing citrus peel nanofibers.

Recently, many studies have been conducted on the production and use of cellulose nanofibers as high-performance nanofibers obtained from plant resources, including research reports showing that they are lightweight and have more than five times the strength of steel. It is being said. Most of these studies use wood fibers derived from wood pulp from softwoods, hardwoods, and the like.

Methods for producing cellulose nanofibers from these wood fibers include the grinder method using a stone mill type friction machine such as an attritor, the underwater head-to-head collision method, and the high-pressure homogenizer method, but the process must be repeated many times. . In addition, there is a method that uses a chemical treatment called TEMPO oxidation to selectively introduce carboxyl groups onto the cellulose surface, which allows cellulose nanofibers with a uniform width of about 4 nm to be easily obtained. It is necessary to introduce carboxyl groups to the surface, and it is not possible to obtain cellulose nanofibers that have not been chemically modified.

In Patent Document 1, plant-derived cellulose nanofibers with a width of 10 to 50 nm can be efficiently obtained by stirring a plant-derived fiber aggregate that does not contain any lignin or contains a specific amount of lignin in a liquid substance. It has been reported that. However, the process of removing lignin requires chemical treatment.

In addition, Patent Document 2 reports that by incorporating cellulose nanofibers into foods, it is possible to improve strength and hardness and improve texture such as chewiness, and the cellulose nanofibers used in this invention are patented. It can be produced by the method described in Document 3.

Patent Document 3 reports a method for producing microfibers that do not contain micron-order fibers and have a uniform fiber diameter with an average fiber diameter of nanometer size, but this production method uses a special homogenizer. It is disclosed that the homogenization process is repeated 5 to 100 times.

It is known that citrus peel contains various functional components such as a large amount of dietary fiber and polymethoxyflavones. However, although most of the juice residue such as citrus peels generated in citrus juice factories is used as livestock feed or fertilizer after pressing, the majority of it is currently disposed of as industrial waste. Use is desired. Unlike wood, citrus peel has food functionality, and if it can be made into nanofibers without chemical treatment, it has the potential to be used in ways other than wood. Furthermore, if nanofibers can be easily produced from citrus peels, costs can be reduced.

Japanese Patent Application Publication No. 2010-216021 Japanese Patent Application Publication No. 2013-236585 Japanese Patent Application Publication No. 2011-26760

The present invention provides a method for producing citrus peel nanofibers that can efficiently defibrate the fiber width down to the nano level without chemically treating citrus peel with enzymes or drugs, and a method for producing citrus peel nanofibers, which can be obtained by the manufacturing method. The present invention aims to provide citrus peel nanofibers that can be produced, and food or cosmetic compositions containing the nanofibers.

As a result of extensive research to achieve the above objective, the present inventors have found that by treating citrus peels with Comitrol and then defibrating them, it is possible to relatively easily produce nanoparticles while retaining the functionality of the peels. We obtained the knowledge that it can be defibrated into fibers. Furthermore, by adding citrus peel nanofibers that can be obtained by such a method to fruit juice, the dispersibility of fruit juice can be improved, and the viscosity can be restored even after freezing or drying. It has been found that when it is in the form of a dry powder, it also has excellent water absorbency.

The present invention was completed based on these findings and further studies, and includes the following citrus peel nanofibers, food or cosmetic compositions containing the nanofibers, and methods for producing citrus peel nanofibers. It provides:

Item 1. Citrus peel nanofibers with a width of 2 to 10 nm,
Nanofibers with a thixotropic index of 2 to 10 when made into an aqueous dispersion with a solid content concentration of 0.5 to 10% by mass.
Item 2. Item 2. The nanofiber according to Item 1, further comprising at least one selected from the group consisting of auraptene, naringin, narirutin, hesperidin, sinensetin, nobiletin, heptamethoxyflavone, and tangeretin.
Item 3. The citrus fruits include Kawachi Bankan, Satsuma Mandarin, Ponkan, Kiyomi, Shiranui, Iyokan, Orange, Lemon, Lime, Yuzu, Amanatsu, Hassaku, Pomelo, Grapefruit, Amanpei, Ehime Kaken No. 28, Natsumikan, and Setoka. , Kara, Harumi, Harehime, Haruka, Minamitsukai, Navel Orange, Amakusa, Marihime, Hyuga Summer, Tarocco, Daidai, Himenotsuki, Encore, Seminole, Kabosu, Moro, Jabara, Tamami, Kogankan, Anseikan , Tenka, Sudachi, Kumquat, Sweet Spring, Reiko, Murcott, Tsunoka, Hime Koharu, Shikuwasa, Himeakari, Nishinoka, Sanbokan, Southern Yellow, Aiotome, Chandra Pomelo, Orange Hinata, Kishu Mikan, Hayaka Item 2. The nanofiber according to Item 1 or 2, which is at least one selected from the group consisting of , Vanpeille, Yukou, Fukuhara Orange, Aurastar, and Butsutekan.
Item 4. The nanofiber according to any one of Items 1 to 3, which is in a dry powder form or a frozen state.
Item 5. Item 5. The nanofiber according to any one of items 1 to 4, which is in the form of a dry powder and has a water absorption rate of 1000% or more.
Item 6. Item 5. A food or cosmetic composition comprising the nanofiber according to any one of Items 1 to 5.
Section 7. Item 7. The composition according to Item 6, which is a thickener, gelling agent, shape preservative, emulsifier or dispersion stabilizer.
Section 8. A method for producing citrus peel nanofibers having the following steps (1) and (2):
(1) Process of crushing citrus peel into paste,
(2) A step of defibrating the citrus peel paste obtained in step (1).
Item 9. Item 9. The manufacturing method according to Item 8, wherein in the step (1), the pulverization process is performed using a high-speed shear stirrer.
Item 10. In item 8 or 9, in step (2), the defibration treatment is performed using a stone mill mill, a high-pressure homogenizer, a refiner, a twin-screw extruder, a water jet method, an underwater counter-collision method, a bead mill, a ball mill, or a microfluidizer. Manufacturing method described.
Item 11. Item 11. The production method according to any one of Items 8 to 10, wherein in the step (1), citrus peel that has been soaked in water in advance is used.

According to the method for producing citrus peel nanofibers of the present invention, the fiber width can be efficiently increased while retaining the functionality of the peel without chemical treatment with enzymes or drugs or complicated manufacturing processes. It can be defibrated down to the nano level.

Furthermore, the citrus peel nanofibers of the present invention can improve the dispersibility of fruit juice by adding them to fruit juice, and furthermore, when in the form of a dry powder, they have high water absorption.

3 is a photograph showing a SEM image after six times of disk mill treatment in Example 1. 3 is a graph showing the functional component concentration for each number of disk mill treatments in Example 1. 2 is a graph showing the viscosity for each number of disk mill treatments in Example 2 (solid content 5%). It is a graph showing the viscosity for each number of disk mill treatments in Example 3 (solid content 3%). It is a graph showing the viscosity for each number of times of disk milling in Example 4 (solid content 3%). It is a graph showing the viscosity for each drying condition in Example 5 (solid content 5%). It is a graph showing the viscosity for each freezing condition in Example 6 (solid content 3%). It is a graph showing the viscosity for each number of high-pressure homogenizer treatments (75 MPa) in Example 7 (solid content 3%). It is a graph showing the viscosity for each number of high-pressure homogenizer treatments (150 MPa) in Example 7 (solid content 3%). FIG. 7 is a diagram showing the analysis results of fiber width from an AFM photograph of nanofibers derived from Kawachi Bankan fruit peel (75 MPa, one-time treatment) in Example 7. FIG. 7 is a diagram showing the results of a solution stability test of nanofibers in Kawachi Bankan fruit juice in Example 8. Top left: Binfis standard manufactured by Sugino Machine Co., Ltd. Top right: Nanofibers derived from the outer pericarp and mesocarp of Kawachi Bankan, Bottom: Nanofibers derived from the capsule of Kawachi Bankan

The present invention will be explained in detail below.

Note that in this specification, the term "comprise" includes the meanings of "essentially consist of" and "consist of".

The citrus peel nanofibers of the present invention are characterized by having a width of 2 to 10 nm and a thixotropic index of 2 to 10 when made into an aqueous dispersion with a solid content concentration of 0.5 to 10% by mass.

Citrus fruits in the present invention are preferably Kawachi Bankan, Unshu Mandarin, Ponkan, Kiyomi, Shiranui (Dekopon (registered trademark)), Iyokan, orange, lemon, lime, yuzu, Amanatsu, Hassaku, pomelo, grapefruit, and sweet. Taira, Ehime Kaken No. 28 (Beni Madonna (registered trademark)), Natsumikan, Setoka, Kara, Harumi, Harehime, Haruka, Minamitsukai, Navel Orange, Amakusa, Marihime, Hyuganatsu, Tarocco, Daidai, Himenotsuki, Encore, Seminole, Kabosu, Moro, Jabara, Tamami, Kogankan, Anseikan, Tenka, Sudachi, Kumquat, Sweet Spring, Reiko, Murcott, Tsunoka, Hime Koharu, Shikuwasa, Himeakari, Nishiyuki Incense, Sanpokan, Southern Yellow, Aiotome, Chandra Pomelo, Orange Hinata, Kishu Mandarin, Hayaka, Banpeiyu, Yukou, Fukuhara Orange, Aura Star, and Butsutekan, more preferably Kawachi Bankan, Unshu Mandarin, Ponkan, and Iyokan. Especially preferred is Kawachi Bankan. Citrus fruits can be used singly or in combination of two or more.

Kawachi Bankan is a type of pomelo (Citrus maxima, Citrus grandis) and is a natural hybrid descended from pomelo.

The citrus pericarp in the present invention refers to the exocarp (flavedo), mesocarp (albedo), carpal membrane, and gizzard, and preferably the exocarp, mesocarp, and carp membrane. If the functionality derived from the citrus peel is to be utilized, the exocarp and mesocarp are preferred, and if it is desired to improve dispersibility and viscosity, the carpal membrane, which has a high cellulose content, is preferred. In addition, each can be used differently for each purpose, but by mixing them, various characteristics can be created. In addition, when making use of the color derived from citrus peel, exocarp is preferable.

As the citrus fruit peel, for example, one obtained after squeezing citrus fruit can be used. Citrus peels obtained by any method of squeezing can be used without restriction, and examples of the squeezing methods include in-line squeezing, belt squeezing, chopper pulper squeezing, and the like. In in-line juicing, whole citrus fruits are placed in a lower cup one by one, a hole is made in the bottom of the fruit and the upper cup is pressed from the top, and the pulp enters a strainer tube where it is squeezed through an orifice to extract the juice. Chopper pulper juice extraction is characterized by extracting the juice after peeling the fruit skin, so it is possible to use peeled fruit skin before juice extraction.

Citrus peels may be fresh, frozen, dried, or cut into pieces. The method for drying citrus peels is not particularly limited, and examples thereof include solar drying, ventilation drying, forced drying, freeze drying, and the like. As a method for cutting the citrus fruit peel, various known cutting or crushing methods used in the food field can be used.

Citrus peel nanofibers can be obtained by defibrating citrus peels. The citrus peel nanofibers of the present invention are preferably citrus peel cellulose nanofibers. The method for producing citrus peel nanofibers of the present invention is not particularly limited, and any known method can be used, and preferably the method described below is preferred.

The fiber width of the citrus peel nanofibers of the present invention is usually 2 to 50 nm, preferably 2 to 10 nm, more preferably 2 to 5 nm.

The thixotropic index (hereinafter sometimes referred to as "TI value") is the viscosity ratio obtained by dividing the viscosity value measured at a rotational speed of 6 rpm by the viscosity value measured at 60 rpm. The viscosity value is determined by preparing an aqueous solution of the citrus peel nanofibers of the present invention with a solid content concentration of 0.5 to 10% by mass, preferably at 20°C, using a viscometer at a rotation speed of 6 rpm or 60 rpm (especially after 1 minute). This is what was measured. Viscosity measurement can be performed, for example, according to JISK5101-6-2. The solid content in the solid content concentration herein does not include monosaccharide and disaccharide sugar content. Examples of the viscometer include a B-type rotational viscometer (DV-III Ultra, manufactured by Brookfield). The TI value is preferably between 4 and 10.

The citrus peel nanofibers of the present invention have a viscosity at 10 rpm of usually 5,000 mPa·S or more, preferably 10,000 mPa·S or more, more preferably 15,000 mPa·S or more when made into an aqueous dispersion with a solid content concentration of 5% by mass. It is. The conditions for measuring viscosity are the same as above.

The citrus peel nanofibers of the present invention desirably contain one or more functional components such as auraptene, naringin, narirutin, hesperidin, sinensetin, nobiletin, heptamethoxyflavone, tangeretin, and β-cryptoxanthin.

The form of the citrus peel nanofibers of the present invention is not particularly limited, and examples include paste, jelly, solution, suspension, emulsion, powder, granule, and solid. The citrus peel nanofibers of the present invention can also be made into a dry powder, and in this case, the viscosity can be restored by adding liquid again. It can also be stored in a frozen state, and its viscosity can be restored to some extent even after thawing.

The citrus peel nanofibers of the present invention have high water absorption when in the form of dry powder. The water absorption rate of the citrus peel nanofibers of the present invention is preferably 1000% or more, more preferably 1500% or more, and even more preferably 2000% or more. The water absorption rate here is a value measured by the method described in Examples.

The citrus peel nanofibers of the present invention are not only composed of nanofibers alone, but also include the above-mentioned functional components, fibers remaining without being converted into nanofibers after fibrillation treatment, and aggregates of nanofibers. It is meant to include things that include things.

The food or cosmetic composition of the present invention is characterized by containing the citrus peel nanofibers described above.

The food composition of the present invention includes all foods and drinks that can be ingested by animals (including humans). The types of food and beverages are not particularly limited, and include, for example, beverages (tea, yogurt drinks, juices, fruit juice drinks, soft drinks, milk, soy milk, coffee, sports drinks, carbonated drinks, alcoholic beverages, etc.); confectionery ( Pudding, crackers, biscuits, cookies, cakes, jelly, candy, chocolate, chewing gum, ice cream, baked goods, Japanese sweets, etc.); Foods (bread, hardtack, udon, soba, ramen, pasta, ham, tofu, konjac, tsukudani) , gyoza, croquettes, salad, curry, jam, etc.); Seasonings (miso, soy sauce, dressing, mayonnaise, sauce, furikake, soup base, etc.); Dairy products (yoghurt, cheese, butter, etc.); Fishery paste products (chikuwa, (kamaboko, jakoten, etc.); and rice-derived products (rice crackers, mochi, etc.).

The food composition of the present invention includes foods and drinks intended for health, health maintenance, promotion, etc., such as health foods, functional foods, nutritional supplements, supplements, foods for specified health uses, foods with nutritional function claims, and foods with functional claims. Foods are also included.

In addition to the citrus peel nanofibers mentioned above, the food composition of the present invention also contains vitamins, minerals, flavonoids, quinones, polyphenols, sweeteners, amino acids, nucleic acids, essential fatty acids, refreshing Various agents, emulsifiers, binders, disintegrants, lubricants, colorants, fragrances, stabilizers, preservatives, brighteners, sustained release modifiers, surfactants, excipients, solubilizers, wetting agents, etc. Additives can be added.

The cosmetic composition of the present invention includes all cosmetics that are applied to the skin, mucous membranes, body hair, hair, scalp, nails, teeth, facial skin, lips, etc. of animals (including humans).

The dosage form of the cosmetic composition of the present invention is aqueous solution type, solubilized type, emulsion type, powder type, oil liquid type, gel type, ointment type, aerosol type, water-oil two-layer type, water-oil-powder type. A wide range of dosage forms can be adopted, such as a three-layer system.

The use of the cosmetic composition of the present invention is also arbitrary; for example, basic cosmetics include lotions, milky lotions, creams, essences, gels, serums, packs, masks, etc., and make-up cosmetics include , foundation, lipstick, blusher, eyeliner, eye shadow, mascara, etc. Nail cosmetics include nail polish, base coat, top coat, nail polish remover, etc. In addition, facial cleansers, (paste or liquid) ) Toothpaste, mouthwash, massage agent, cleansing agent, shaving cream, aftershave lotion, pre-shave lotion, body soap, soap, shampoo, conditioner, hair treatment, hair conditioner, hair tonic agent, hair growth agent, antiperspirant, Examples include bath salts and sunscreen creams.

In addition to the above-mentioned citrus peel nanofibers, the cosmetic composition of the present invention contains ingredients commonly used in cosmetics, such as whitening agents, humectants, oily ingredients, antioxidants, ultraviolet absorbers, surfactants, and enhancers. Adhesives, alcohols, powder components, coloring materials, aqueous components, water, various skin nutrients, and the like can be blended as appropriate.

The proportion of the citrus peel nanofibers contained in the food or cosmetic composition of the present invention is usually 0.01 to 99% by mass, preferably 1 to 80% by mass, and more preferably 10 to 70% by mass.

The food or cosmetic composition of the present invention includes additives that impart a thickening effect, a gelling effect, a shape-retaining effect, or a dispersion stabilizing effect, that is, a thickening agent, a gelling agent, a shaping agent, an emulsifier, or a dispersing agent. It can also be used as a stabilizer.

The method for producing citrus peel nanofibers of the present invention is characterized by having the following steps (1) and (2).
(1) Process of crushing citrus peel into paste,
(2) A step of defibrating the citrus peel paste obtained in step (1).

The citrus peel used in step (1) is the same as that described above. Before the pulverization treatment, the citrus peel may be subjected to treatments such as washing, draining, and cutting.

For the crushing treatment, it is preferable to use citrus peels that have been soaked in water in advance. By immersing it in water, water-soluble pectin etc. are eluted, and the cellulose content becomes relatively high, making it possible to prepare nanofibers with higher viscosity. Furthermore, bittern components can also be eluted, and bittern can also be removed.

Furthermore, blanched citrus peels can also be used in the crushing treatment of citrus peels. Blanching involves soaking citrus peels in hot water, usually at a temperature of 50 to 100 degrees Celsius. Blanching time is usually about 1 to 30 minutes, preferably about 5 to 15 minutes.

For the pulverization treatment of citrus peels, it is preferable to use citrus peels mixed with a liquid such as water.

The method for crushing citrus peels is not particularly limited as long as the citrus peels can be made into a paste, and examples include using a high-speed cutting and stirring machine. Examples of the high-speed cutting agitator include Comitrol (registered trademark), pulper finisher, electric mill, colloid mill, food processor, rotary cutter mill, Micromeister, and the like. As the method for the pulverization treatment, it is preferable to use Comitrol. By using Comitrol, the number of defibration treatments can be greatly reduced, and the defibration process can be performed smoothly without clogging. Comitrol is preferably applied with an opening of 0.02 to 0.30 mm, more preferably an opening of 0.12 to 0.13 mm. By performing such a pulverization process, it is possible to prepare the desired nanofibers even if the number of defibration processes is reduced.

In step (1), sterilization treatment, cooling treatment, etc. can be further performed.

The defibration treatment in step (2) is not particularly limited, and any known method can be used. , conical refiner, etc.), twin-screw extruder, water jet method, underwater counter collision method, bead mill, ball mill, microfluidizer, etc. The defibration treatment is preferably performed using a stone mill type mill or a high-pressure homogenizer, and more preferably a high-pressure homogenizer in terms of efficiency. The crushing pressure of the high-pressure homogenizer is preferably 20 to 200 MPa, more preferably 40 to 150 MPa, and even more preferably 50 to 100 MPa. The defibration treatment can be carried out singly or in combination of two or more.

The solid content concentration of the citrus peel paste used in the defibration treatment is preferably 0.5 to 10% by mass, more preferably 1 to 5% by mass.

According to the method for producing citrus peel nanofibers of the present invention, the fiber width can be efficiently increased while retaining the functionality of the peel without chemical treatment with enzymes or drugs or complicated manufacturing processes. It can be defibrated down to the nano level.

Furthermore, the citrus peel nanofibers of the present invention can improve the dispersibility of fruit juice by adding them to fruit juice, and furthermore, when in the form of dry powder, they have high water absorption.

Examples are given below to explain the present invention in more detail. However, the present invention is not limited to these Examples in any way. In addition, in the examples, the pericarp means the exocarp and mesocarp unless otherwise specified.

<Example 1>
400 g of Kawachi Bankan fruit skin was hydrothermally treated at 120°C for 10 minutes, crushed with a spatula, and then made into nanofibers under the following processing conditions.

・Disc mill conditions Equipment used: Masuko Co., Ltd., Super Mascolloider (model number: MKCA6-2)
Disc type used: GC6-120
Rotation speed: 1800rpm
Clearance conditions: 1st time 300-400μm, 2nd time 300μm, 3rd time 250μm, 4th time 200μm, 5th time 200μm, 6th time 180μm
*To set the clearance, set the scale dial to 3 at the position where the upper and lower discs barely touched each other, and define this position as a clearance of 300μm. From that position, the scale dial was further narrowed, and the short scale was set at 10 μm, which was used as the clearance value.

・How to prepare samples for scanning electron microscopy (SEM) observation
(i) Kawachi Bankan fruit peel nanofibers diluted approximately 1000 times with distilled water (solid content approximately 0.005%) were filtered using 0.1 μm filter paper (ADVANTEC H010A025A).
(ii) After filtration, the filter paper was washed with ethanol, transferred to a Petri dish filled with ethanol, the ethanol was discarded, and the Petri dish was filled with ethanol again.
(iii) The operation of discarding the ethanol in the petri dish and replacing it with t-butyl alcohol was performed five times.
(iv) After replacing with t-butyl alcohol, it was placed in a refrigerator and frozen.
(v) After freezing, the Petri dish was warmed, and the filter paper was cut into 5 mm squares with a scalpel, transferred to a freeze-drying cup, and freeze-dried.
(vi) The freeze-dried filter paper was attached to a SEM plate, and osmium was vapor-deposited along with the plate to prepare a sample for observation.

As a result, SEM images confirmed that nanofibers had been formed (Figure 1). As a result of separating samples after each mechanical treatment and analyzing the functional components derived from the pericarp, it was confirmed that there was almost no loss of functional components during the mechanical processing process, and functionality was maintained (Figure 2 ).

<Example 2>
After processing the peel of Kawachi Bankan in boiling water for 10 minutes, approximately 4.5 L of the product was coarsely ground in a food processor and subjected to disk mill processing in the same manner as in Example 1 under the processing conditions shown below. At the time of viscosity measurement, the water content was diluted to 95%.
Clearance conditions: 1st time 250μm, 2nd time 180μm, 3rd time 150μm, 4th time 150μm

As a result, measurements using a viscometer (DV-III Ultra, Brookfield Co., Ltd.: Spindle, V-73) under the measurement conditions shown in Table 1 confirmed that each time the pericarp was processed, the fibers of the peel progressed and the viscosity increased. It was done (Figure 3).

<Example 3>
The peel of Kawachi Bankan was treated in boiling water for 10 minutes, then exposed to water for 24 hours, and coarsely ground in a food processor. Approximately 4.5 L of the peel was subjected to disk mill treatment in the same manner as in Example 1 under the treatment conditions shown below. . At the time of viscosity measurement, the water content was diluted to 97%.
Clearance conditions: 1st time 250μm, 2nd time 180μm, 3rd time 150μm, 4th time 150μm

As a result, measurements using a viscometer confirmed that the viscosity increased as the peel progressed with each treatment (Figure 4), and even though the solid content was 3%, which was lower than in Example 2, the viscosity increased. It was about the same level. This is thought to be because water-soluble pectin and the like were eluted by exposure to water, resulting in a relatively high cellulose content.

Next, we analyzed the constituent sugars and galacturonic acid to understand changes in the composition of cellulose and other components due to exposure of the peel to water.

(1) Analysis of ethanol/toluene extract Place 180 ml of ethanol/toluene solution (1:2) in a round-bottomed flask, accurately weigh approximately 1 g of each sample on a thimble filter, and use a 6-h Soxhlet extractor to extract the solvent. The components were extracted, and the samples before and after extraction were accurately weighed to calculate the amount of ethanol/toluene extract. The residue after extraction was used for subsequent analysis of constituent sugars and galacturonic acid.

(2) Analysis of constituent sugars The constituent sugars contained in the citrus nanofiber paste were analyzed according to the Laboratory analytical Procedure (Sluiter, A. et al., Technical report NREL/TP-510-42618 (2012)). 600 μL of 72% sulfuric acid solution was added to 50 mg of the dry sample, and the mixture was stirred at 30° C. for 1 hour. Thereafter, it was diluted with 16.8 mL of distilled water and subjected to hydrolysis treatment at 120°C for 1 hour using an autoclave. After the hydrolysis treatment, the sample was neutralized with calcium carbonate, and the neutral sugar contained in the sample was measured using a high performance liquid chromatograph and a differential refractive index detector.

・High performance liquid chromatography measurement conditions Column oven temperature: 80°C, flow rate: 0.6 mL/min, mobile phase: ultrapure water Column: HPX-87P, 300 mm x 7.8 mm, Bio-Rad Laboratories Inc., USA

(3) Analysis of galacturonic acid Pectin, which is polygalacturonic acid contained in the citrus nanofiber paste, was decomposed into galacturonic acid, which is a monomer, using pectinase (from Aspergillus niger, Sigma-Aldrich Co. LLC, USA). 20 mg of sample and 10 mg of enzyme were added to 25 mL of acetate buffer (pH 4.0) and stirred in an incubator at 50°C for 2 days. After the enzyme treatment, galacturonic acid was measured using a high performance liquid chromatograph and a differential refractive index detector.

・High performance liquid chromatography measurement conditions Column oven temperature: 60°C, flow rate: 0.6 mL/min, mobile phase: 5 mM Sulfuric acid column: HPX-87H, 300 mm x 7.8 mm, Bio-Rad Laboratories Inc., USA

Note that the cellulose concentration can be converted by multiplying the glucose concentration result by 0.9.

As shown in Table 2, based on the constituent sugar glucose, it was confirmed that the Kawachi Bankan peel nanofibers without water bleaching and with water bleaching contained about 15% and 22% cellulose, respectively. It was confirmed that by exposing to water, the amount of cellulose increased while the ethanol/toluene extract decreased.

<Example 4>
Furthermore, by examining the pretreatment method of raw materials, we investigated efficient nano-processing technology using only mechanical processing.

The citrus peel used as the raw material was the Kawachi Bankan peel discharged from the juicer during juice extraction, which was washed, drained, and then cut into approximately 1 cm squares using a dicer. Next, it was blanched at 95°C for 10 minutes, cooled with water, and then drained. The same amount of water was added to the diced peel, and the peel was treated with Comitrol at 0.12 mm, followed by sterilization and cooling to produce Kawachi Bankan peel paste. 4 L of this paste sample was subjected to disk mill treatment in the same manner as in Example 1 under the treatment conditions shown below. In addition, when measuring the viscosity, it was diluted to have a water content of 97%.
Clearance conditions: 150μm for the first time

As a result, measurements using a viscometer confirmed that the fibrillation of the pericarp proceeded and the viscosity increased with only one treatment (Figure 5).

<Example 5>
The peel of Kawachi Bankan was treated in boiling water for 10 minutes, then coarsely ground in a food processor, and subjected to disk mill treatment in the same manner as in Example 1 under the treatment conditions shown below. Dry the obtained triple-treated paste by freeze drying (dielectric freezer, -30℃), shelf drying at 60℃, or drum dryer (120℃), and measure the viscosity after dispersing the solution again to a water concentration of 95%. did.
Clearance conditions: 180μm for the first time, 150μm for the second time, 150μm for the third time

As a result, measurements using a viscometer confirmed that the viscosity recovered by approximately 70% when dried on a shelf at 60°C (Figure 6).

<Example 6>
The peel of Kawachi Bankan was treated in boiling water for 10 minutes, then exposed to water for 22 hours, coarsely ground in a food processor, and subjected to disk mill treatment in the same manner as in Example 5. The obtained paste treated three times was diluted to a water concentration of 97%, then frozen at -20°C, -30°C, and -80°C, and the viscosity was measured after thawing.

As a result, the viscosity recovered by more than 50%, and it was confirmed that the lower the freezing temperature, the greater the viscosity recovery (Figure 7).

<Example 7>
The paste sample used in Example 4 was treated with a high-pressure homogenizer (Panda PLUS 2000, manufactured by GEA Nilosoabi) three times at a pressure of 75 MPa and twice at a pressure of 150 MPa. At the time of viscosity measurement, the water content was diluted to 97%. As a result, measurements using a viscometer confirmed that the viscosity increased as the number of treatments increased, and the viscosity increased as the treatment pressure increased (FIGS. 8 and 9).

Furthermore, as a result of analyzing the functional components for each of these treatments, as shown in Table 3, most of the functional components were retained.

Furthermore, the obtained sample was prepared by the following method and observed with an atomic force microscope (JSPM-5200, manufactured by JEOL, hereinafter referred to as AFM). As shown in Figure 10, it was found that the sample had been defibrated to the nano-level. The fiber width was approximately 2 to 5 nm. These results can be similarly confirmed for Iyokan, Satsuma mandarin, and Ponkan, and as a result of aggregating the average width of 20 fibers analyzed by AFM observation, fibers with a width of 2 to 10 nm were confirmed. As shown in Table 4, the average width was about 2 to 5 nm. Furthermore, when the Kawachi Bankan sac membrane was crushed using a food processor and then treated three times at a pressure of 75 MPa using a high-pressure homogenizer, fibers with an average size of around 3 nm were observed in each treatment, as shown in Table 4. It was done.

・Auraptene pretreatment method in nanofibers
(1) Approximately 0.1 g of the freeze-dried sample was weighed into a plastic centrifuge tube (50 ml), 15 ml of acetone was added, and ultrasonic extraction was performed for 10 minutes.
(2) Filter using 5C filter paper and wash with acetone and ethanol.
(3) Concentrate to 0.5 ml using a rotary evaporator and make up to 10 ml.
(4) The diluted solution was passed through a 0.2 μm filter and used as a sample for analysis.

・Pretreatment method for flavanone and polymethoxyflavone in nanofibers
(1) Approximately 0.05 g of the freeze-dried sample was weighed, 5 ml of extraction solvent (MeOH:DMSO=1:1) was added, mixed with a vortic mixer, subjected to ultrasonic extraction for 10 minutes, and left for over 1 hour.
(2) After centrifugation at 10,000 rpm for 10 minutes, the supernatant was added to a graduated cylinder with a stopper.
(3) 1 ml of extraction solvent was added to the precipitate, mixed with a vortic mixer, and then subjected to ultrasonic extraction for 10 minutes.
(4) After centrifugation at 10,000 rpm for 10 minutes, the supernatant was added to the beaker from (2), 1 ml of extraction solvent was added to the precipitate, mixed again with a vortic mixer, and then subjected to ultrasonic extraction for 10 minutes.
(5) After centrifugation at 10,000 rpm for 10 minutes, the supernatant was taken into the beaker of (2), and distilled water was added to the combined extract with the supernatant so that the solvent concentration was 10% (V/V).
(6) The sample was passed through a solid phase extraction disk (Bond Elut (C18, 500 mg)) that had been conditioned sequentially with 3 ml of methanol and 6 ml of 10% (V/V) methanol.
(7) After washing with 15 ml of 10% (V/V) methanol and elution with 5 ml of extraction solvent, the volume was adjusted to a fixed volume in a 5 ml volumetric flask, and passed through a 0.2 μm filter to prepare a sample for analysis.

・Analysis conditions ○LC/MS system: ACQUITY UPLC, Waters Q-TOF micro
○Column: BEH C18 (1.7μm, 2.1 mm×100 mm)
○Column temperature: 40℃
○Detector: PDA
○Mobile phase conditions etc.
[Auraptene] Flow rate: 0.3 ml/min, water containing 10 mM ammonium formate: methanol = 25:75
[Polymethoxyflavone] Flow rate: 0.25 ml/min, water containing 10 mM ammonium formate: acetonitrile = 60:40
[Flavanone] Flow rate: 0.25 ml/min
Eluent A Acetonitrile
Eluent B 10 mM ammonium formate in water
Gradient conditions (eluent A): 80% (0 → 4 minutes), 80 → 60% (4 → 5 minutes), 60% (5 → 6 minutes), 60 → 30% (6 → 7 minutes), 30% (7 → 10 minutes), 30 → 80% (10 → 10.5 minutes), 80% (10.5 → 12 minutes)

- Preparation before AFM observation - Approximately 10 ml of diluted solution was prepared to make a solution with a solid content of 0.1%.
・The above solution was further diluted 10 times and 1.5 ml was prepared in a 2 ml centrifuge tube.
・Ultrasonic treatment was performed at 100 μA for 30 seconds.
・Silicon wafers cut into approximately 5 mm squares were immersed in 1% PEI (polyethyleneimine) for 10 minutes or more, washed with ultrapure water, and dried by removing the water with N ₂ gas. A silicon wafer was set in a spin coater, 80 μl of a solution treated with ultrasound was dropped onto the substrate, and after being left for 1 minute, the spin coater was started at 3000 rpm for 60 seconds to serve as an observation sample.

<Example 8>
Each of the following nanofibers was added to Kawachi Bankan Finisher fruit juice so that the solid content concentration was 0.6%, and the mixture was further diluted 10 times. This solution was measured every 2 minutes for a total of 30 minutes using a solution stability evaluation device (TURBISCAN MA2000) (light source: pulsed LED 850 nm).
(1) Sugino Machine Co., Ltd. Binfis standard
(2) Kawachi Bankan outer pericarp mesocarp High pressure homogenizer treated nanofiber (150MPa 2 passes) (3) Kawachi Bankan capsule membrane high pressure homogenizer treated nanofiber (75MPa 3 passes)

As a result, the wood pulp-derived Vinfils standard began to agglomerate the earliest, whereas the nanofibers derived from the outer pericarp and mesocarp of Kawachi Bankan agglomerated slightly, while the nanofibers derived from the orocarp did not agglomerate at all. (Figure 11).

<Example 9>
Immediately after the sample of Example 7, in which the peel paste of each citrus fruit was nano-processed using a high-pressure homogenizer, was prepared by rotating the spindle at 6 rpm for 1 minute using a B-type rotational viscometer (DV-III Ultra manufactured by Brookfield). Viscosity measurements were taken immediately after spinning the spindle at 60 rpm for 1 minute. The data after 1 minute were selected for each, and the TI values were calculated and shown in Table 5. As a result, it was found that these TI values were around 7, indicating that they had large thixotropic properties.

The TI value was measured by the method specified in JISK5101-6-2 (Pigment Test Methods - Part 6: Fluidity - Section 2: Rotational Viscometer Method), and was calculated using the following formula.
・TI value = Apparent viscosity at 6 rpm / Apparent viscosity at 60 rpm

<Example 10>
Samples 1 and 2 in Table 6 were obtained from commercial products.

Preparation of samples 3, 4, and 6 in Table 6: Each citrus peel was treated in boiling water for 10 minutes (sample 6 was exposed to water for 24 hours), then coarsely ground in a food processor, and then disk milled at a clearance of 200 μm. Conducted twice. Further, the mixture was treated twice at 150 MPa using a high-pressure homogenizer, sterilized at 90°C for 15 minutes, freeze-dried, and coarsely ground using a food processor.

Preparation of sample 5 in Table 6: The paste sample used in Example 4 was treated twice at a pressure of 150 MPa using a high-pressure homogenizer, then sterilized at 90°C for 15 minutes, and then freeze-dried. and coarsely ground it in a food processor.

Method for measuring water absorption: 1.00 g of each powder of Samples 1 to 6 in a dry state was placed in a 50 mL tube, 40 g of distilled water was added, and the tube was left overnight at room temperature. After centrifuging this tube at 3000 rpm for 30 minutes, the supernatant was discarded, and the weight of the powder after water absorption (the total weight of the powder and water absorbed by the powder) was measured. The water absorption rate was calculated using the following formula.
Water absorption rate (%) = (Powder weight after water absorption - Powder weight before water absorption (1.00 g)) / Powder weight before water absorption (1.00 g) x 100

The results are shown in Table 6. As a result of measuring the water absorption rate using each citrus peel dry powder, all of the citrus-derived nanofibers had a water absorption rate of 1000% or more. In particular, Iyokan and Kawachibankan had a water absorption rate of over 2000%.

Claims (11)

Citrus peel nanofibers with a width of 2 to 10 nm,
Nanofibers with a thixotropic index of 2 to 10 when made into an aqueous dispersion with a solid content concentration of 0.5 to 10% by mass. The nanofiber according to claim 1, further comprising at least one selected from the group consisting of auraptene, naringin, narirutin, hesperidin, sinensetin, nobiletin, heptamethoxyflavone, and tangeretin. The citrus fruits include Kawachi Bankan, Satsuma Mandarin, Ponkan, Kiyomi, Shiranui, Iyokan, Orange, Lemon, Lime, Yuzu, Amanatsu, Hassaku, Pomelo, Grapefruit, Amanpei, Ehime Kaken No. 28, Natsumikan, and Setoka. , Kara, Harumi, Harehime, Haruka, Minamitsukai, Navel Orange, Amakusa, Marihime, Hyuga Summer, Tarocco, Daidai, Himenotsuki, Encore, Seminole, Kabosu, Moro, Jabara, Tamami, Kogankan, Anseikan , Tenka, Sudachi, Kumquat, Sweet Spring, Reiko, Murcott, Tsunoka, Hime Koharu, Shikuwasa, Himeakari, Nishinoka, Sanbokan, Southern Yellow, Aiotome, Chandra Pomelo, Orange Hinata, Kishu Mikan, Hayaka The nanofiber according to claim 1 or 2, wherein the nanofiber is at least one selected from the group consisting of , Vanpeille, Yukou, Fukuhara Orange, Aurastar, and Butsutekan. Nanofibers according to any one of claims 1 to 3, which are in dry powder form or frozen state. The nanofiber according to any one of claims 1 to 4, which is in the form of a dry powder and has a water absorption rate of 1000% or more. A food or cosmetic composition comprising the nanofiber according to any one of claims 1 to 5. The composition according to claim 6, wherein the food or cosmetic composition is a thickener, gelling agent, shape preservative, emulsifier, or dispersion stabilizer. A method for producing citrus peel nanofibers having the following steps (1) and (2):
(1) Process of crushing citrus peel into paste,
(2) A step of defibrating the citrus peel paste obtained in step (1). The manufacturing method according to claim 8, wherein in the step (1), the pulverization treatment is performed using a high-speed shear stirrer. 9. In the step (2), the defibration treatment is performed using a stone mill, a high-pressure homogenizer, a refiner, a twin-screw extruder, a water jet method, an underwater counter-collision method, a bead mill, a ball mill, or a microfluidizer. The manufacturing method described in. The manufacturing method according to any one of claims 8 to 10, wherein in the step (1), citrus peel that has been soaked in water in advance is used.