Cocoa-derived pulp, cocoa-derived cellulose nanofiber, and methods of making the same

Abstract

The present invention provides a new technical means for effectively and safely producing CNF having long fiber length and pulp components containing the same. More specifically, the present invention relates to a method for producing a cocoa-derived pulp, which includes a step of digesting a cocoa-derived raw material with an alkaline solution.

Description

[0001] Reference to relevant applications

[0002] This patent application claims priority based on Japanese Patent Application No. 2023-215198, filed on December 20, 2023, the entire disclosure of which is incorporated herein by reference as part of the disclosure of the invention. Technical Field

[0003] This invention relates to cocoa pulp, cocoa cellulose nanofibers, and methods for manufacturing them. Background Technology

[0004] In recent years, nanotechnology, aimed at miniaturizing materials to the nanoscale and obtaining new physical properties different from the original properties of the materials, has attracted attention. In particular, cellulose nanofibers (hereinafter sometimes simply referred to as "CNFs") are mainly known as functional biomass raw materials for highly nanoscale (micro-refining) wood fibers (pulp) obtained from wood to nanoscales of less than one-hundredth of 1 micrometer. Cellulose produced by plants exhibits the morphology of tiny fibers such as microfibrils. CNFs are those in which microfibrils dissociate into bundles ranging from one to dozens or hundreds of fibers, and have a width on the nanoscale. In addition, CNFs are derived from plant fibers, and therefore have the characteristics of low environmental impact and lightweight in terms of production and waste. Since the function and application of CNFs are greatly affected by fiber length and fiber width, it is desirable to efficiently obtain CNFs with various fiber lengths and widths.

[0005] As raw materials for CNFs, woody biomass such as coniferous trees, broadleaf trees, and bamboo, as well as woody biomass materials derived from wood, such as construction waste, sawdust, wood chips, and recycled paper, are commonly used. In addition to wood, various plant-derived raw materials, such as rice straw, sugarcane bagasse, and agricultural waste, also contain cellulose and can therefore be used as CNF raw materials. Various CNF manufacturing methods utilizing such raw materials are reported.

[0006] For example, Patent Document 1 reported obtaining cellulose nanocrystal particles from wheat bran and measuring the average diameter and average length. The results showed that the average diameter was 27.5 ± 3.5 nm and the average length was about 300 to 1000 nm.

[0007] Furthermore, Patent Document 2 reports the manufacture of cellulose nanofibers and pulp components containing almond skins as raw materials. Regarding the manufacturing conditions for the pulp made from almond skins, conditions involving a high level of alkali concentration and high temperature are applied, where the raw material is maintained at 170°C in a solution with a sodium hydroxide concentration of 15%.

[0008] However, when using woody biomass raw materials and agricultural waste as described above, pulping is required to obtain CNFs, which necessitates processing the raw materials under typically stringent conditions such as chemical treatment and high-temperature processing, sometimes resulting in excessive energy costs. Furthermore, the function and properties of CNFs can vary depending on their size; therefore, CNFs of the desired size are preferred if they can be selectively and easily obtained. In particular, long-fiber CNFs are expected to be used as raw materials for the manufacture of high-performance materials and functional additives. However, when using conventionally known wood and waste as raw materials, it is difficult to stably manufacture long-fiber CNFs under mild conditions while keeping energy costs low.

[0009] On the other hand, cocoa ( Theobroma cacao The seeds of cocoa beans are called cocoa beans and are processed into cocoa mass, which is widely used as a food ingredient. A typical method for preparing cocoa mass involves extracting cocoa beans from cocoa pods, fermenting the extracted beans, drying the fermented beans, roasting the dried beans, and removing the outer skin (cocoa husk) to produce cacao nibs. These cacao nibs are then ground to produce cocoa mass. This manufacturing process produces byproducts such as cocoa pods and cocoa husks, which are typically discarded on farms as organic fertilizer. To the knowledge of the inventors, no methods have been reported for efficiently obtaining cellulose nanofibers from cocoa-derived raw materials, such as cocoa pods and cocoa husks.

[0010] Existing technical documents

[0011] Patent documents

[0012] Patent Document 1: Japanese Patent Application Publication No. 2022-152003

[0013] Patent Document 2: Japanese Patent Application Publication No. 2020-165042 Summary of the Invention

[0014] One of the objectives of this invention is to provide a new technical means for efficiently and safely manufacturing CNFs with long fiber lengths and producing pulp thereof.

[0015] The inventors conducted in-depth research and discovered that using alkali to distill cocoa-derived raw materials can efficiently and safely produce long-fiber CNFs and pulp components containing them. This invention is based on the above insights.

[0016] According to one embodiment of the present invention, a method for manufacturing cocoa-derived pulp is provided, comprising: a step of evaporating cocoa-derived raw materials with an alkaline solution.

[0017] Furthermore, according to another embodiment of the present invention, a cocoa-derived pulp is provided, which satisfies at least one of the following (A) to (C):

[0018] (A) The proportion of fibers with a length of 100µm or more relative to the total number of fibers is 50% or more;

[0019] (B) The proportion of fibers with a length of 250µm or more is 30% or more relative to the number of fibers other than those derived from soft cells.

[0020] (C) The cellulose crystallinity is above 40%.

[0021] In addition, according to another embodiment of the present invention, a method for manufacturing cellulose nanofibers derived from cocoa is provided, which includes a step of defibrating the above-mentioned pulp derived from cocoa.

[0022] Furthermore, according to another embodiment of the present invention, a cellulose nanofiber derived from cocoa is provided, which satisfies at least one of the following (D) to (H):

[0023] (D) The proportion of fibers with a length of more than 1000 nm in the cellulose nanofibers derived from cocoa is more than 40%.

[0024] (E) The proportion of fibers with a fiber width of less than 5 nm in the cocoa-derived cellulose nanofibers is more than 50%.

[0025] (F) The average aspect ratio is 200 or higher;

[0026] (G) The crystallinity of cellulose is above 40%;

[0027] (H) The viscosity of the 1 w / w% aqueous suspension of cellulose nanofibers derived from cocoa is above 900 mPa·s.

[0028] According to the present invention, CNFs with long fiber lengths and pulp components comprising them can be manufactured efficiently and safely. According to the present invention, CNFs with long fiber lengths and narrow fiber widths can be manufactured efficiently and safely under mild conditions using cocoa or its processing byproducts. According to the present invention, compared to conventional raw materials such as wood materials, steam decomposition can be carried out under mild conditions, thus providing an advantage in avoiding fiber decomposition and providing CNFs with long fiber lengths and narrow fiber widths.

[0029] Furthermore, as in this invention, the utilization of agricultural waste and byproducts generated during cocoa processing for higher value-added applications is considered beneficial not only to preventing annual losses at the production site but also to multiple stakeholders, including farmers (additional income), industry (new value-added components), and consumers (new and innovative products). It is believed that utilizing processing byproducts that would otherwise be considered waste, as in this invention, is related to reducing environmental impact and contributes to achieving the SDGs (Sustainable Development Goals). Attached Figure Description

[0030] Figure 1 This indicates the fiber length distribution and cumulative ratio of fibers in cocoa pulp (Ca48, Ca49, Ca50, Ca51).

[0031] Figure 2 These are photographs taken using a transmission electron microscope of CNF in a CNF suspension obtained from cocoa bean husk pulp. A is a photograph at 90,000x magnification, B is a photograph at 36,000x magnification, and C is a photograph at 18,000x magnification.

[0032] Figure 3 These are photographs taken using a transmission electron microscope of CNF in a CNF suspension obtained from pulp (cedar caustic soda AQ pulp) produced by simmering cedar trees using the anthraquinone caustic soda process (AQ). A is a photograph at 90,000x magnification, B is a photograph at 35,000x magnification, and C is a photograph at 16,000x magnification.

[0033] Figure 4 This indicates the fiber length distribution and cumulative ratio of CNF obtained from cocoa pulp (Ca48, Ca49, Ca50, Ca51).

[0034] Figure 5 This indicates the fiber width distribution and cumulative ratio of CNF obtained from cocoa pulp (Ca48, Ca49, Ca50, Ca51).

[0035] Figure 6 This represents the relationship between the intensity of cellulose crystals and the intensity of amorphous materials in X-ray diffraction patterns measured in the range of 5-40°. The crystallinity is then calculated using this intensity.

[0036] Figure 7This represents the X-ray diffraction patterns of CNFs (Ca75, Ca76, Ca77, Ca78) obtained from cocoa pulp (Ca48, Ca49, Ca50, Ca51). Here, Ca75 corresponds to Ca48, Ca76 corresponds to Ca49, Ca77 corresponds to Ca50, and Ca78 corresponds to Ca51.

[0037] Figure 8 The time-dependent change in sedimentation level of a suspension sample obtained by ultrasonic treatment (4 minutes) of cocoa pulp (Ca48, Ca50, Ca51) or cedar pulp (sulfate process (KP) treated or untreated) in the sedimentation test of Example 7-1.

[0038] Figure 9 The time-dependent change in sedimentation level of a suspension sample obtained by ultrasonic treatment (1 minute) of cocoa-derived pulp (Ca48, Ca50, Ca51) obtained from cocoa bean shells in the sedimentation test of Example 7-2 is shown.

[0039] Figure 10 These are photographs of ultrasonically treated samples (Ca48, Ca50, Ca51) derived from cocoa bean husks, taken 1 hour (1h) and 5 hours (5h) after the start of the experiment.

[0040] Figure 11 The time-dependent change in sedimentation level of a suspension sample obtained by ultrasonic treatment (4 minutes) of cocoa-derived pulp (Ca43, Ca44, Ca45, Ca46, 47) obtained from cocoa pods in the sedimentation test of Example 7-3 is shown.

[0041] Figure 12 This is a photo of CNF film made from cocoa pulp. Detailed Implementation

[0042] <Manufacturing method of cocoa pulp>

[0043] According to one embodiment of the present invention, as described above, the method for manufacturing cocoa-derived pulp includes a step of distilling cocoa-derived raw materials with an alkaline solution. According to this manufacturing method, even under mild conditions, CNF with long fiber length and narrow fiber width, suitable for the manufacture of various high-performance products, can be provided easily and efficiently. Furthermore, cocoa-derived raw materials can be distilled without pretreatment such as pulverization as with woody biomass raw materials, thus making them a preferred raw material in terms of reducing energy costs.

[0044] As mentioned above, when using cocoa-derived raw materials, the energy cost for producing CNFs with long fiber lengths and narrow fiber widths is significantly lower compared to wood biomass and agricultural waste. Furthermore, the distillation process of cocoa-derived raw materials allows for the use of safe chemicals until nanofibers are obtained, which is advantageous for industrial production.

[0045] According to one embodiment of the invention, a manufacturing byproduct containing plant fibers is preferably used as the raw material derived from cocoa. Here, plant fibers refer to those containing at least cellulose, though the exact amount varies depending on the raw material, but generally include cellulose, hemicellulose, lignin, protein, and lipids. Cellulose and hemicellulose are examples of components required for the manufacture of CNFs.

[0046] Furthermore, according to a preferred embodiment of the present invention, the manufacturing byproducts containing plant fibers are byproducts generated during the food manufacturing process when screening parts intended for use as food components. Such byproducts may include, for example, in foods using fruits or seeds, the remaining parts other than those intended for food use, such as fruit slices, fruit peels, and seed portions, as well as seed shells, peels, fragments, etc. Suitable examples of such cocoa-derived raw materials include cocoa pods (hereinafter, sometimes only referring to the outer shell of the cocoa fruit) and cocoa bean shells.

[0047] According to one embodiment of the present invention, it is preferable to use an alkaline solution containing an alkali agent to perform a vaporization treatment on the above-mentioned cocoa-derived raw material. This vaporization treatment removes lignin and other components other than cellulose and hemicellulose from the cocoa-derived raw material. Therefore, the vaporization treatment is also called a delignification treatment.

[0048] As the aforementioned alkaline agent, alkali metal hydroxides commonly used in alkaline distillation can be used, preferably any one of lithium hydroxide, sodium hydroxide, potassium hydroxide, and sodium carbonate, and more preferably sodium hydroxide (caustic soda). The method of pulping using caustic soda is called alkaline distillation, in which the raw material is distilled with caustic soda at high temperature to obtain pulp. In alkaline distillation, lignin is subjected to the action of caustic soda, undergoing molecular weight reduction and dissolution through the cracking of phenyl ethers.

[0049] It should be noted that, for wood, sodium sulfide and caustic soda sulfate (KP) are commonly used for distillation, but sometimes the odor emitted by sulfur becomes a problem. On the other hand, if an alkaline distillation method is used as in this invention, it does not contain sulfur components from the distillation liquid, and therefore does not produce the problem of sulfur-derived odor.

[0050] The amount of alkali used can be adjusted appropriately according to the type and amount of cocoa-derived raw material used. The concentration of the alkali in the alkaline solution is, for example, 1 w / w% or more and 8 w / w% or less, preferably 1.5 w / w% or more and 5.5 w / w% or less, more preferably 2 w / w% or more and 5 w / w% or less. Furthermore, relative to 100 parts by weight of the solid components of the cocoa-derived raw material, 10 parts by weight or more and 50 parts by weight or less (preferably 15 parts by weight or more and 30 parts by weight or less) of alkali can be added. The weight ratio of the solid components of the cocoa-derived raw material to the alkaline solution (weight of solid components of cocoa-derived raw material: weight of alkaline solution) can be set, for example, to 1:3 to 1:50. In this case, the liquid ratio can be adjusted by immersing the entire amount of solid components of the cocoa-derived raw material in the alkaline solution.

[0051] Solvents used in alkaline solutions include water, alcohol and water mixtures, with water being the most common.

[0052] In the above-mentioned evaporation process, evaporation aids can be used together with alkali agents.

[0053] Distillation aids are agents added to the distillate to promote delignification and prevent carbohydrate dissolution. They can be one or more of the following: quinone compounds such as anthraquinone, dihydroanthraquinone, tetrahydroanthraquinone, methylanthraquinone, methyldihydroanthraquinone, methyltetrahydroanthraquinone, benzoquinone, naphthoquinone, and phenanthrenequinone; hydroquinone compounds such as anthraquinone, methylanthraquinone, dihydroanthraquinone, or their alkali metal salts; and precursors and polysulfides such as anthrone, anthraquinol, methylanthraquinone, and methylanthraquinol. Anthraquinone is an excellent distillation aid that promotes delignification and stabilizes carbohydrates, used at approximately 0.1 w / w% relative to the raw material. Anthraquinone oxidizes and stabilizes the terminal aldehyde groups of cellulose and hemicellulose in wood, becoming anthraquinone itself. Then, anthraquinone acts as a reducing agent, reducing the molecular weight of lignin in the pulp fragments, while simultaneously reverting to anthraquinone. Therefore, it also has the advantage of reducing the amount of alkali required to obtain the same kappa number (an indicator of the amount of lignin in pulp). The above-mentioned evaporation aid is preferably used at a ratio of 0.001 parts by weight or more and 1.0 parts by weight or less relative to 100 parts by dry weight of the raw material derived from cocoa.

[0054] The temperature for performing the simmering treatment (simmering temperature) can be set to a lower temperature compared to the case where wood is used as raw material, for example, 50°C or higher and 160°C or lower, preferably 80°C or higher and 160°C or lower, and more preferably 80°C or higher and 140°C or lower.

[0055] From the perspective of reducing energy costs, the evaporation process is preferably carried out within a short time. After reaching the target temperature, the evaporation process is preferably within 3 hours, more preferably 30 minutes or more but less than 3 hours, more preferably 1 hour or more but less than 2.5 hours, and even more preferably 2 hours or more but less than 3 hours.

[0056] Furthermore, since the distillation process is carried out within the aforementioned temperature range, it is preferable to use a pressure vessel (or a pressure vessel if large) when processing at temperatures exceeding 100°C. According to one embodiment of the invention, after distillation, the pressure is released, and the vessel is cooled to a temperature at which it can be removed.

[0057] According to one embodiment of the invention, it is preferable to wash the cocoa-derived pulp obtained after the simmering process. For example, the cocoa-derived pulp obtained by the simmering process can be separated from the simmering liquid, and the cocoa-derived pulp can be washed with water. Here, distilled water, purified water, or water based on these can be used. Typically, cocoa-derived pulp has a high moisture content, so a washing process can be performed while forcibly removing the moisture from the pulp using a vacuum filter, centrifugal dewatering machine, press, etc. The end of the washing process can be determined by checking the pH or the turbidity of the washing liquid.

[0058] According to one embodiment of the present invention, cocoa-derived pulp obtained by simmering can be further subjected to bleaching treatment. This bleaching treatment can be carried out by treating the cocoa-derived pulp with a bleaching solution containing a bleaching agent. Even with the above-described simmering treatment, lignin may not be completely removed in some cases; in such cases, bleaching treatment can be used to further remove residual lignin.

[0059] According to one embodiment of the invention, any one of sodium hypochlorite (NaClO), hydrogen peroxide (H2O2), ozone (O3), oxygen (O2), persulfate (H2SO5), peracetic acid (C2H4O3), or mixtures thereof can be used as the bleaching agent in the bleaching process.

[0060] Bleaching is preferably carried out by appropriately setting the pH and temperature conditions to produce the desired bleaching effect. For example, the solids concentration of the pulp to be bleached is preferably 1% to 30%, but it can be outside this range if necessary. The bleaching process can be a multi-stage bleaching process involving repeated bleaching of the same material, or a multi-stage bleaching process combining different types of bleach.

[0061] For example, when using sodium hypochlorite as a bleaching agent, a solution of sodium hypochlorite with an effective chlorine content of 0.1 w / w% or more and 10 w / w% or less can be prepared and used.

[0062] During bleaching, the temperature is usually kept above 0℃ and below 110℃, and the bleaching process is completed within 0.25 hours to 5 hours.

[0063] After bleaching, the resulting cocoa pulp is typically washed. Vacuum filtration, centrifugal dewatering, or pressing can be used to wash the bleached and washed cocoa pulp until the filtered water reaches a pH of approximately 7.

[0064] <Cocoa pulp>

[0065] According to one embodiment of the invention, cocoa-derived pulp is provided, obtained through the above-described evaporation treatment and, according to a desired bleaching treatment. According to one embodiment of the invention, the cocoa-derived pulp comprises fibers derived from soft cells, vascular bundle cells, and fiber cells (fiber cells other than vascular bundle cells). Furthermore, according to a preferred embodiment of the invention, the cocoa-derived pulp comprises vascular bundles or a portion of fibers derived therefrom. From the viewpoint of supplying CNFs with long fiber lengths, it is preferable that the cocoa-derived pulp comprises vascular bundles or a portion of fibers derived therefrom.

[0066] In cocoa-derived raw materials, the fibers in fibroblasts are generally 260–500 µm long, those in soft cells are about 100 µm long, and the fibers in helical vascular bundles are several mm long when unwound. Although not bound by theory, through distillation under mild conditions, the helical fibers constituting the vascular bundles in cocoa-derived raw materials can be unwound without damage and included in cocoa-derived pulp while maintaining their long fiber length. Therefore, it is believed that the proportion of long fibers in cocoa-derived pulp is increased.

[0067] In this specification, the determination of fiber length in cocoa pulp can be performed with reference to JISP 8226-2 Pulp - Method for determination of fiber length based on automated optical analysis - Part 2: Unpolarized light method. Specifically, it can be pre-calibrated according to JIS P8226-2, and ImageJ (National Institutes of Health (NIH) Rasband 1997-2023) can be used in the determination of fiber length.

[0068] According to one embodiment of the invention, the length-weighted average fiber length of the fibers contained in the cocoa pulp, as specified in JIS P8226-2, is, for example, 300µm or more and 1000µm or less, preferably 350µm or more and 950µm or less, and more preferably 400µm or more and 900µm or less.

[0069] In addition, according to one embodiment of the present invention, the fiber contained in the cocoa pulp has a number-average fiber length specified according to JISP8226-2, for example, 150µm or more and 1000µm or less, preferably 180µm or more and 700µm or less, and more preferably 200µm or more and 550µm or less.

[0070] Furthermore, according to one embodiment of the present invention, the proportion of fibers with a fiber length of 100µm or more relative to the total number of fibers in the cocoa-derived pulp is, for example, 25% or more, preferably 35% or more, more preferably 45% or more, and even more preferably 50% or more. Here, in this specification, the determination of the proportion of the total number of fibers in the cocoa-derived pulp to the proportion of fibers with each fiber length can be determined by the method described in the examples described later.

[0071] Furthermore, according to one embodiment of the present invention, in the cocoa pulp, the proportion of fibers with a length of 100µm or more relative to the number of fibers other than those derived from soft cells is, for example, 50% or more, preferably 55% or more, more preferably 60% or more, and even more preferably 65% ​​or more.

[0072] In addition, according to one embodiment of the present invention, the proportion of fibers having a fiber length of 200µm or more relative to the total number of fibers in the cocoa pulp is, for example, 25% or more, preferably 30% or more.

[0073] Furthermore, according to one embodiment of the present invention, in the cocoa pulp, the proportion of fibers with a length of 200 µm or more relative to the number of fibers other than those derived from soft cells is, for example, 25% or more, preferably 30% or more, more preferably 35% or more, and even more preferably 40% or more.

[0074] In addition, according to one embodiment of the present invention, the proportion of fibers with a fiber length of 250µm or more relative to the total number of fibers in the cocoa pulp is, for example, 25% or more, preferably 30% or more.

[0075] In addition, according to one embodiment of the present invention, in the cocoa pulp, the proportion of fibers with a length of 250µm or more relative to the number of fibers other than those derived from soft cells is, for example, 30% or more, preferably 35% or more, more preferably 40% or more, and even more preferably 45% or more.

[0076] In addition, according to one embodiment of the present invention, the proportion of fibers with a fiber length of 450µm or more relative to the total number of fibers in the cocoa pulp is, for example, 5% or more, preferably 10% or more.

[0077] Furthermore, according to one embodiment of the present invention, in the cocoa pulp, the proportion of fibers with a length of 450 µm or more relative to the number of fibers other than those derived from soft cells is, for example, 10% or more, preferably 20% or more, more preferably 30% or more, and even more preferably 45% or more.

[0078] Furthermore, according to one embodiment of the present invention, cocoa-derived pulp can exhibit a high level of crystallinity. In this specification, the crystallinity of cocoa-derived pulp and CNF derived therefrom can be determined by using an X-ray diffraction apparatus (accelerating voltage 40 kV) to obtain spectra of test samples in the range of 5-40°, determining the intensity of crystalline and amorphous materials based on the spectra, and calculating the crystallinity according to the formula shown below.

[0079] Crystallinity (%) = (Strength of crystal / (Strength of crystal + Strength of amorphous solid)) × 100

[0080] According to one embodiment of the present invention, the crystallinity of the cocoa-derived pulp is, for example, 40% or more, preferably 40% or more and 80% or less, more preferably 40% or more and 70% or less, and even more preferably 42% or more and 65% or less.

[0081] In addition, according to a preferred embodiment of the invention, the cocoa-derived pulp satisfies at least one of (A) to (C) below.

[0082] (A) The proportion of fibers with a length of 100µm or more relative to the total number of fibers is 50% or more;

[0083] (B) The proportion of fibers with a length of 250µm or more is 30% or more relative to the number of fibers other than those derived from soft cells.

[0084] (C) The cellulose crystallinity is above 40%.

[0085] In the preferred embodiment of the present invention described above, the cocoa-derived pulp may satisfy all of (A) to (C), or satisfy one or two of them; from the viewpoint of manufacturing high-performance materials, it is preferable to satisfy all of them. In the preferred embodiment of the present invention, a more specific manner of (A) to (C) may be achieved by applying the values ​​of the parameters described in the embodiments of the present invention described above.

[0086] Furthermore, as mentioned above, cocoa pulp contains a large amount of long, thin fibers, thus exhibiting the property of prolonged dispersion and non-settling in solution. According to one embodiment of the invention, the sedimentation rate determination method described below can be used as an indicator of this property of dispersion and non-settling in solution. In the sedimentation rate determination method specified below, the scale level of the graduated cylinder serves as an indicator of sedimentation rate; the higher the scale level at the end of the test, the lower the sedimentation rate, indicating dispersion and suspension in water.

[0087] Settling velocity determination method: 100 mL of a 0.1 w / w% mixture obtained by adding distilled water to 0.1 g (dry weight) of cocoa-derived pulp is treated with an ultrasonic homogenizer for 4 minutes to obtain a 0.1 w / w% suspension. This suspension is then poured into a 100 mL graduated cylinder (according to JIS R3505) and allowed to stand. The upper limit of the settling fraction of the cocoa-derived pulp is measured at regular intervals.

[0088] According to a preferred embodiment of the present invention, in the above-described settling velocity measurement method, the scale of the cocoa pulp at 72 hours is, for example, 50 cc or more, preferably 60 cc or more, more preferably 70 cc or more, further preferably 80 cc or more, and even more preferably 90 cc or more.

[0089] <Manufacturing Method of Cellulose Nanofibers (CNF)>

[0090] According to one embodiment of the present invention, CNF derived from cocoa can be obtained by defibrinating the cocoa-derived pulp obtained above. Examples of methods for defibrinating cocoa-derived pulp include mechanical defibrinating methods (e.g., defibrinating methods using a milling machine, a high-pressure homogenizer such as a water jet machine, or defibrinating methods using ultrasonic treatment), acid hydrolysis methods (e.g., sulfuric acid hydrolysis), chemical treatment methods (e.g., TEMPO oxidation using 2,2,6,6-tetramethylpiperidine-1-oxygen radical (TEMPO), and enzymatic hydrolysis methods (e.g., methods using cellulase). Mechanical defibrinating is preferred for defibrinating cocoa-derived pulp.

[0091] According to the method of the present invention, long-fiber CNFs can be efficiently and easily generated through a simple mechanical defibrillation process. It is generally considered that nano-sizing of pulp components presents certain difficulties because, in the case of pulp derived from lignocellulosic biomass, CNFs tend to immediately and tightly aggregate after purification and drying. Once aggregated, breaking up these agglomerates requires significant energy, such as that from a high-pressure homogenizer. However, in the present invention, CNFs derived from cocoa can be effectively obtained by performing a simple mechanical defibrillation method on cocoa-derived pulp.

[0092] According to a preferred embodiment of the invention, the above-described mechanical defiberization method is carried out by ultrasonic treatment. It is an unexpected fact that such a simple method as ultrasonic treatment can efficiently produce CNF from cocoa-derived pulp in a short time.

[0093] The nano-sizing process in one embodiment of the present invention will be described more specifically. Prior to nano-sizing, the moisture content of cocoa pulp is measured, and the solids content is calculated. Based on this, water is added to adjust the pulp solids content to be 0.01 w / w% or more and 5 w / w% or less. Next, CNF is obtained by irradiation treatment using an ultrasonic homogenizer for approximately 1 to 4 minutes continuously.

[0094] After nanofiberization is completed by mechanical defiberization, the processed material is dried as needed. From the point of view of preventing bacterial contamination, it can be filled into any container, sterilized and stored.

[0095] <Cellulose nanofibers (CNF) derived from cocoa>

[0096] According to one embodiment of the present invention, a cocoa-derived CNF obtained by the above method is provided. The cocoa-derived CNF of the present invention has a high proportion of elongated CNFs, which can be advantageously utilized in the manufacture of high-performance materials.

[0097] According to one embodiment of the present invention, the length-weighted average fiber length of the fibers contained in the CNF derived from cocoa is, for example, 300 nm or more, preferably 600 nm or more, and more preferably 900 nm or more.

[0098] In addition, according to one embodiment of the present invention, the number-average fiber length of CNF derived from cocoa is, for example, 1000 nm or more, preferably 1000 nm or more and 7000 nm or less, preferably 1100 nm or more and 6000 nm or less, and more preferably 1150 nm or more and 5500 nm or less.

[0099] Furthermore, according to one embodiment of the present invention, the proportion of fibers having a fiber length of 1000 nm or more relative to the total number of CNFs derived from cocoa is, for example, 40% or more, preferably 60% or more, more preferably 70% or more, further preferably 80% or more, and even more preferably 90% or more.

[0100] Furthermore, according to one embodiment of the present invention, the proportion of fibers having a length of 2000 nm or more relative to the total number of CNFs derived from cocoa is, for example, 50% or more, preferably 60% or more, more preferably 70% or more, further preferably 80% or more, and even more preferably 90% or more.

[0101] Furthermore, according to one embodiment of the present invention, the average fiber width of the CNF derived from cocoa is, for example, 10 nm or more, preferably 8 nm or less, and more preferably 5 nm or less. Additionally, the range of the average fiber width of the CNF derived from cocoa is preferably 3 nm or more and 8 nm or less, and more preferably 3 nm or more and 5 nm or less.

[0102] Furthermore, according to one embodiment of the present invention, the proportion of fibers having a fiber width of 5 nm or less relative to the total number of fibers in CNF derived from cocoa is, for example, 50% or more, preferably 60% or more, more preferably 70% or more, further preferably 80% or more, and even more preferably 90% or more.

[0103] In this specification, the determination of average fiber length and average fiber width of CNF based on electron microscopy observation can be performed as follows.

[0104] A CNF-containing slurry is prepared and cast onto a hydrophilically treated, coated mesh made of carbon, plastic, or other materials to create a sample for transmission electron microscopy (TEM) observation. Alternatively, it can be cast onto glass or mica for atomic force microscopy (AFM) image observation. Depending on the width of the fibers, observation is performed using a TEM at any magnification range of 1000x, 5000x, 10000x, 20000x, 50000x, or 100000x. The sample, observation conditions, and magnification are adjusted to meet the following criteria.

[0105] (1) Fibers are distributed at any part of the observed image to capture the image.

[0106] (2) Next, the fiber length and fiber width of the fibers present in the captured images were determined using ImageJ (National Institutes of Health (NIH) Rasband 1997-2023).

[0107] Specifically, regarding fiber length, for fibers within an image, ImageJ's fiber length measurement function is used to extend a line along the fiber to the same length, and the distance from the initial point to the final point of the obtained line is measured using software. For the obtained distance, the actual length is calculated using Excel's spreadsheet function based on the scale recorded in each image. The lengths of at least 40 fibers read in this way are measured, and the length-weighted average fiber length and the number-average fiber length are determined.

[0108] Additionally, regarding fiber width, for fibers within an image, ImageJ's fiber length measurement function is used to select an almost isolated portion of the fiber within the image. The distance between the width of fibers perpendicular to the fiber is measured, and the software is used to measure the distance between the thickness of the resulting fibers. Similarly, for the fiber length measurement, the actual length is calculated using Excel's spreadsheet function based on the scale recorded in each image.

[0109] The width of at least 40 fibers read in this way can be measured and averaged to obtain the average fiber width.

[0110] Furthermore, according to one embodiment of the present invention, the average aspect ratio of the CNF derived from cocoa is, for example, 200 or more, preferably 300 or more, more preferably 400 or more, and even more preferably 500 or more. In this specification, the above-mentioned average aspect ratio can be calculated by the following formula.

[0111] (Average aspect ratio) = (Number average fiber length) / (Average fiber width)

[0112] Furthermore, according to one embodiment of the present invention, CNF derived from cocoa can exhibit high crystallinity. According to one embodiment of the present invention, the crystallinity of CNF derived from cocoa is, for example, 40% or more, preferably 40% or more and 80% or less, more preferably 40% or more and 70% or less, and even more preferably 45% or more and 65% or less.

[0113] Furthermore, the CNF derived from cocoa of the present invention exhibits high viscosity when suspended / dissolved in water. According to one embodiment of the present invention, the viscosity of a 1 w / w% aqueous suspension of the CNF derived from cocoa at 22-23°C is, for example, 900 mPa·s or more, preferably 950 mPa·s or more. Additionally, the upper limit of the viscosity of a 1 w / w% aqueous suspension of the CNF derived from cocoa at 22-23°C is, for example, 2000 mPa·s or less, preferably 1500 mPa·s or less. Furthermore, the viscosity range of a 1 w / w% aqueous suspension of the CNF derived from cocoa at 22-23°C is, for example, 900 mPa·s or more and 1500 mPa·s or less, preferably 950 mPa·s or more and 1200 mPa·s or less. The above viscosity can be measured using a type B viscometer as described in the examples described later.

[0114] In addition, according to one embodiment of the present invention, cocoa-derived cellulose nanofibers satisfying at least one of (D) to (H) are provided.

[0115] (D) The proportion of fibers with a length of more than 1000 nm in the above-mentioned cellulose nanofibers derived from cocoa is more than 40%.

[0116] (E) The proportion of fibers with a fiber width of less than 5 nm in the above-mentioned cellulose nanofibers derived from cocoa is more than 50%.

[0117] (F) The average aspect ratio is 200 or higher;

[0118] (G) The crystallinity of cellulose is above 40%;

[0119] (H) The 1 w / w% aqueous suspension of the above-mentioned cellulose nanofibers derived from cocoa has a viscosity of 900 mPa·s or higher at 22~23°C.

[0120] In the preferred embodiment of the present invention described above, the CNF derived from cocoa can satisfy all of (D) to (H), or satisfy 1 to 4 of them; from the viewpoint of manufacturing high-performance materials, it is preferable to satisfy all of them. In a more specific manner of the present invention, (D) to (H) can be expressed by applying the values ​​of the parameters described in one embodiment of the present invention described above.

[0121] Furthermore, as mentioned above, CNF derived from cocoa contains a large amount of long, thin fibers, and therefore, like pulp derived from cocoa, it can exhibit the property of long-term dispersion and non-settling in solution. According to a preferred embodiment of the invention, in the above-described sedimentation rate measurement method, the scale reading of CNF derived from cocoa at 72 hours is, for example, 80 cc or more, preferably 90 cc or more.

[0122] It should be noted that the cocoa-derived pulp and CNF of the present invention are not limited to the above, and the standards can be determined by various methods. Specifically, the dry weight, crystal structure, light transmittance, fiber width and height, fiber length, molecular weight distribution, solid content of supernatant, thermal stability, ash content, acid-soluble metal content, organic pollutant content, acetone-soluble substance content, and constituent sugar content can also be determined according to the international standard ISO / TS21346.

[0123] According to one embodiment of the present invention, the following solution is provided.

[0124] [1] A method for manufacturing cocoa pulp, comprising: a step of evaporating cocoa-derived raw materials with an alkaline solution.

[0125] [2] According to the method described in [1], the raw material derived from cocoa is cocoa bean shell or cocoa pod.

[0126] [3] According to the method described in [1] or [2], wherein the temperature of the alkaline solution is above 80°C and below 140°C.

[0127] [4] The method according to any one of [1] to [3], wherein the concentration of the alkaline agent in the alkaline solution is 1 w / w% or more and 8 w / w% or less.

[0128] [5] The method according to any one of [1] to [4], wherein the above-mentioned evaporation time is within 3 hours.

[0129] [6] A cocoa pulp that satisfies at least one of the following (A) to (C):

[0130] (A) The proportion of fibers with a length of 100µm or more relative to the total number of fibers is 50% or more;

[0131] (B) The proportion of fibers with a length of 250µm or more is 30% or more relative to the number of fibers other than those derived from soft cells.

[0132] (C) The cellulose crystallinity is above 40%.

[0133] [7] According to [6], the cocoa-derived pulp, wherein in (A), the proportion of fibers having a length of 200 µm or more relative to the total number of fibers is 35% or more.

[0134] [8] According to [6] or [7], the total fiber number is the sum of fibers obtained from soft cells, vascular bundle cells and fiber cells.

[0135] [9] The cocoa pulp according to any one of [6] to [8], wherein the proportion of fibers having a length of 450 µm or more is 40% or more relative to the number of fibers other than those derived from soft cells.

[0136]

[10] Pulp derived from cocoa according to any one of [6] to [9], wherein, in the sedimentation rate determination method specified below, the graduation level of the graduated cylinder (according to JIS R3505) as an indicator of sedimentation rate is 80 cc or more at 72 hours.

[0137] The sedimentation rate determination method is as follows: 100 mL of a 0.1 w / w% mixture obtained by adding distilled water to 0.1 g (dry weight) of cocoa pulp is treated with an ultrasonic homogenizer for 4 minutes to obtain a 0.1 w / w% suspension. Then, the suspension is injected into a 100 mL volumetric cylinder and allowed to stand. The upper limit of the sedimentation rate of the cocoa pulp is measured at regular intervals.

[0138]

[11] The cocoa-derived pulp according to any one of [6] to

[10] , which is obtained by the method of [1].

[0139]

[12] A method for manufacturing cellulose nanofibers derived from cocoa, comprising: a step of defibrating pulp derived from cocoa.

[0140]

[13] According to the method of

[12] , wherein the above-mentioned cocoa-derived pulp is obtained by any one of [1] to [5].

[0141]

[14] According to the method of

[12] or

[13] , wherein the above-mentioned fiber unwinding process is carried out by ultrasonic treatment.

[0142]

[15] A cellulose nanofiber derived from cocoa, which satisfies at least one of the following (D)~(H):

[0143] (D) The proportion of fibers with a length of more than 1000 nm in the above-mentioned cellulose nanofibers derived from cocoa is more than 40%.

[0144] (E) The proportion of fibers with a fiber width of less than 5 nm in the above-mentioned cellulose nanofibers derived from cocoa is more than 50%.

[0145] (F) The average aspect ratio is 200 or higher;

[0146] (G) The crystallinity of cellulose is above 40%;

[0147] (H) The viscosity of the above 1 w / w% aqueous suspension of cellulose nanofibers derived from cocoa is above 900 mPa·s.

[0148]

[16] The cocoa-derived cellulose nanofibers according to

[15] , wherein, in (D), the proportion of fibers having a length of 2000 nm or more in the cocoa-derived cellulose nanofibers is 50% or more.

[0149]

[17] According to

[15] or

[16] , the cellulose nanofibers derived from cocoa, wherein, in the sedimentation velocity determination method specified below, the graduation level of the graduated cylinder (according to JIS R3505) as an indicator of sedimentation velocity is 80 cc or more at 72 hours.

[0150] The sedimentation velocity determination method is as follows: 100 mL of a 0.1 w / w% aqueous suspension is obtained by adding distilled water to 0.1 g (dry weight) of cocoa-derived cellulose nanofibers.

[0151] Next, the suspension was injected into a 100 mL graduated cylinder and allowed to stand. The upper limit of the sedimentation level of the cellulose nanofibers derived from cocoa was measured at intervals of time.

[0152]

[18] The cellulose nanofibers derived from cocoa according to any one of

[15] to

[17] , wherein, in (H), the viscosity is less than 1500 mPa·s.

[0153]

[19] The cellulose nanofibers derived from cocoa according to any one of

[15] to

[18] are obtained by any one of

[12] to

[14] .

[0154] Example

[0155] The present invention will be described in detail below through the following embodiments, but the present invention is not limited to these embodiments. Furthermore, unless otherwise specified, the measurement methods and units described in this specification conform to JIS (Japanese Industrial Standards).

[0156] Example 1: Distillation (pulping) of cocoa bean husks

[0157] 15g (dry weight) of cocoa bean shells and 150g of sodium hydroxide aqueous solution (NaOH concentration 1-8 w / w%) were placed in a stainless steel container. The container was then heated in an oil bath to a temperature of 80-160°C for 2-3 hours. After distillation, the treated material was separated into solid and liquid components using filter paper or filter cloth. The resulting solid fraction was thoroughly washed with water and then squeezed to remove as much moisture as possible, yielding unbleached cocoa pulp.

[0158] The results are shown in Tables 1 and 2. Both results show a tendency for higher pulp yields to be achieved under milder reaction conditions.

[0159] [Table 1]

[0160]

[0161] [Table 2]

[0162]

[0163] Example 2: Bleaching of cocoa pulp

[0164] Add sodium hydroxide aqueous solution (1 w / w%) to 15 g (dry weight) of unbleached cocoa pulp to make a total volume of 280 g. Place this mixture and 20 g (1 g available chlorine) of 5 w / w% sodium hypochlorite aqueous solution into a plastic bag and seal the bag. Heat the bag in a water bath until the temperature inside the bag reaches 40°C, then treat for 1 hour to perform bleaching. After bleaching, perform solid-liquid separation using filter paper or filter cloth. Wash the resulting solid portion thoroughly with water and then squeeze to remove as much water as possible to obtain bleached cocoa pulp. Repeat this process several times until the cocoa pulp reaches the target whiteness.

[0165] The results are shown in Tables 3 and 4. Both results show a tendency for higher pulp yields to be achieved under milder reaction conditions.

[0166] [Table 3]

[0167]

[0168] [Table 4]

[0169]

[0170] Example 3: Determination of fiber length in pulp

[0171] Cocoa pulp

[0172] Undried, unbleached cocoa-derived pulps (Ca48, Ca49, Ca50, Ca51) were suspended in a small amount of distilled water. The resulting samples were placed on glass slides and observed and photographed using a polarizing microscope (Nikon ECLIPSE E600POL). Fiber lengths were measured using ImageJ (National Institutes of Health (NIH) Rasband 1997-2023).

[0173] The fiber lengths (number-average fiber lengths) of cocoa pulp (Ca48, Ca49, Ca50, Ca51) are shown in Table 5-1.

[0174] [Table 5-1]

[0175]

[0176] In addition, the measured values ​​and cumulative ratios of fiber length from cocoa-derived pulp (Ca48, Ca49, Ca50, Ca51) are shown in Tables 5-2 and 5-3, respectively. In particular, the relationship between fiber length and cumulative ratio of cocoa-derived pulp (Ca48, Ca49, Ca50, Ca51) in Table 5-3 is as follows: Figure 1 As shown.

[0177] [Table 5-2]

[0178]

[0179] [Table 5-3]

[0180]

[0181] In addition, cocoa pulp contains fibers containing both soft cells and vascular bundle cells. Therefore, to investigate the compositional ratio of fibers derived from soft cells to those containing vascular bundle cells, cocoa pulp samples were placed on glass slides and observed / photographed using a polarizing microscope. For multiple photographs, the fiber lengths of vascular bundle cells and soft cells were measured separately using ImageJ (National Institutes of Health (NIH) Rasband 1997-2023).

[0182] For the cocoa-derived pulps (Ca48, Ca49, Ca50, Ca51) mentioned above, the fiber length (µm) was measured for samples containing soft cells and samples without soft cells.

[0183] The results are shown in Table 6. It was confirmed that samples containing soft cells tended to have shorter fiber lengths compared to samples without soft cells. This result is attributed to the shorter fibers derived from soft cells.

[0184] Furthermore, it was confirmed that the fiber length of the sample processed at a lower temperature (80°C) tended to be longer compared to the sample processed at a higher temperature (140°C). This result suggests that the lower the processing temperature, the longer the fiber can maintain its length.

[0185] [Table 6]

[0186]

[0187] Pulp derived from cedar trees (reference area)

[0188] Sulfate distillation of cedar wood

[0189] A distillate solution containing 15g of cedar wood material (absolute dry weight), 3g of sodium hydroxide, and 1g of sodium sulfide dissolved in 90g of water was placed in a stainless steel container. The container was heated in an oil bath until the temperature reached 170°C, then treated for 2 hours. Solid-liquid separation was performed using filter paper or filter cloth. The resulting solid fraction was defiberized using a defiberizer and thoroughly washed with water. Finally, it was squeezed to remove as much moisture as possible, yielding cedar wood pulp derived from the sulfate (KP) process (hereinafter also referred to as "unbleached cedar sulfate pulp").

[0190] The results are shown in Table 7.

[0191] [Table 7]

[0192]

[0193] The caustic soda anthraquinone process (caustic soda AQ) for the decomposition of fir materials

[0194] 15g of cedar wood material (absolute dry weight), 90g of sodium hydroxide (caustic soda) aqueous solution (NaOH concentration 2~6 w / w%), and 0.075g of anthraquinone (AQ) were placed in a stainless steel container. The container was heated in an oil bath, and after the temperature inside the container reached 150~170℃, it was treated for 3 hours. Solid-liquid separation was performed on the treated material using filter paper or filter cloth. The obtained solid fraction was defiberized using a defiberizer and thoroughly washed with water. Finally, it was squeezed to remove as much water as possible, yielding unbleached cedar wood pulp treated with caustic soda (AQ) (hereinafter also referred to as "unbleached cedar wood pulp with caustic soda AQ").

[0195] Bleaching of unbleached cedar sulfate pulp and unbleached cedar caustic soda (AQ) pulp

[0196] Add sodium hydroxide aqueous solution (NaOH concentration 1w / w%) to 15g (dry weight) of unbleached cedar sulfate pulp or unbleached cedar caustic soda AQ pulp, making a total weight of 145g. Place this mixture and 5g of 5% sodium hypochlorite aqueous solution (available chlorine content 0.25g) into a plastic bag and seal the bag. Heat the bag in a water bath until the temperature inside the bag reaches 40°C, then treat for 1 hour. Separate the solids from the liquid using filter paper or filter cloth. Wash the resulting solid portion thoroughly with water, then squeeze to remove as much water as possible, obtaining bleached cedar pulp. Repeat this process several times until the target whiteness is achieved.

[0197] Example 4: Manufacturing of cellulose nanofibers (CNF)

[0198] 4-1: Nanoparticles (derived from cocoa pulp)

[0199] Distilled water was added to 1 g (by dry weight) of the prepared undried cocoa bean husk pulp to make a 0.1 wt% aqueous suspension. The suspension was placed in a 100 mL volumetric beaker and treated with an ultrasonic homogenizer (TAITEC VP-30S, 20 kHz) for 4 minutes or 1 minute to obtain a CNF suspension.

[0200] Figure 2 These are photographs taken using a transmission electron microscope of CNF in a CNF suspension obtained from pulp derived from cocoa bean shells. Figure 2 In the image, A is a photo magnified 90,000 times, B is a photo magnified 36,000 times, and C is a photo magnified 18,000 times.

[0201] 4-2: Nanoparticles (Fir sulfate pulp, Fir caustic soda AQ pulp)

[0202] Distilled water was added to 1 g (by dry weight) of undried cedar sulfate pulp or cedar caustic soda AQ pulp to prepare a 1 wt% aqueous suspension. The suspension was then processed using a water jet processing system (manufactured by Sugino Machine) for approximately 10 cycles to obtain a CNF suspension.

[0203] Figure 3 These are photographs taken using a transmission electron microscope of CNF in a CNF suspension obtained from cedar caustic soda AQ pulp. Figure 3 In the image, A is a photo magnified 90,000 times, B is a photo magnified 35,000 times, and C is a photo magnified 16,000 times.

[0204] Example 5: Determination of fiber length and fiber width of CNF derived from cocoa pulp.

[0205] A small amount of cocoa CNF suspension prepared from cocoa-derived samples (Ca48, Ca49, Ca50, Ca51) was suspended in distilled water. The suspension was dropped onto a grid with a plastic support membrane, negatively stained with 4% uranyl acetate, and observed and photographed using a transmission electron microscope (JEM-2000EX, Nippon Electron Ltd., accelerating voltage 200kV). The fiber length and width of the CNF were determined using ImageJ (National Institutes of Health (NIH) Rasband 1997-2023) (mean values ​​are expressed as number averages). The results are shown in Table 8. It can be seen that under various conditions, the finest fiber width and longest fiber length are easily obtained at an alkali concentration of 2% and a treatment temperature of 80℃.

[0206] [Table 8]

[0207]

[0208] Furthermore, the measured fiber lengths and cumulative ratios of CNFs obtained from cocoa-derived pulp (Ca48, Ca49, Ca50, Ca51) are shown in Tables 9-1 and 9-2, respectively. In particular, the relationship between fiber length distribution and cumulative ratio of CNFs obtained from cocoa-derived pulp (Ca48, Ca49, Ca50, Ca51) in Table 9-2 is as follows: Figure 4 As shown.

[0209] [Table 9-1]

[0210]

[0211] [Table 9-2]

[0212]

[0213] Furthermore, the measured fiber width and cumulative ratio of CNF obtained from cocoa-derived pulp (Ca48, Ca49, Ca50, Ca51) are shown in Tables 10-1 and 10-2, respectively. In particular, the relationship between fiber width distribution and cumulative ratio of CNF obtained from cocoa-derived pulp (Ca48, Ca49, Ca50, Ca51) in Table 10-2 is as follows: Figure 5 As shown.

[0214] [Table 10-1]

[0215]

[0216] [Table 10-2]

[0217]

[0218] Example 6: Study on the crystallinity of cocoa pulp and CNF

[0219] Using an X-ray diffraction apparatus (Rigaku Corporation, Smart Lab, accelerating voltage 40kV), spectra of the test samples were taken in the range of 5-40°, and the crystallinity was calculated according to the following formula.

[0220] Crystallinity (%) = (Strength of crystal / (Strength of crystal + Strength of amorphous solid)) × 100

[0221] Here, the strength of crystalline and amorphous materials is as follows: Figure 6 As illustrated.

[0222] It should be noted that for cocoa pulp, air-dried wood was used as the sample.

[0223] In addition, for CNF derived from cocoa pulp, cast films made from a 0.1% CNF suspension were used as samples.

[0224] X-ray diffraction patterns of CNFs (Ca75, Ca76, Ca77, Ca78) obtained from cocoa pulp (Ca48, Ca49, Ca50, Ca51) are shown below. Figure 7 As shown. Here, Ca75 corresponds to Ca48, Ca76 corresponds to Ca49, Ca77 corresponds to Ca50, and Ca78 corresponds to Ca51.

[0225] The obtained spectrum confirmed that CNF is a type I crystal of natural cellulose.

[0226] In addition, the crystallinity of cocoa pulp (Ca48, Ca49, Ca50, Ca51) and CNF derived from it is recorded in Table 11.

[0227] [Table 11]

[0228]

[0229] In addition, as a reference area, the crystallinity of pulp derived from cedar trees and CNF obtained therefrom was calculated using the same method as that for pulp derived from cocoa trees.

[0230] The results are shown in Table 12. Here, "KP" refers to the sulfate distillation treatment described above, and "caustic soda AQ" refers to the distillation treatment based on the above-mentioned caustic soda anthraquinone (caustic soda AQ).

[0231] [Table 12]

[0232]

[0233] Example 7: Study on the settling velocity of CNF obtained by ultrasonic treatment

[0234] 7-1: A study on ultrasonic treatment for 4 minutes (from cocoa bean husk pulp).

[0235] 0.1 g (dry weight) of cocoa-derived pulp obtained from cocoa bean shells was added to distilled water to prepare a 0.1 wt% suspension in 100 mL. The suspension was then treated with an ultrasonic homogenizer for 4 minutes (hereinafter referred to as "nano-sizing") under the experimental conditions shown in Table 13. The resulting CNF-containing liquid was poured into a 100 mL graduated cylinder (JIS R3505) and allowed to stand. The time of pouring was taken as hour 0, and the sedimentation rate was read at intervals. Therefore, starting from the 100 mark, the scale gradually decreased over time while sedimentation was observed, indicating that lower scale values ​​indicate greater sedimentation.

[0236] In addition, the same experiment was conducted using pulp derived from cedar trees as a reference area.

[0237] [Table 13]

[0238]

[0239] The results are as follows Figure 8 As shown. Here, "US4m" refers to a 4-minute ultrasonic treatment. Additionally, "KP" indicates that the aforementioned sulfate distillation treatment was performed.

[0240] No sedimentation was observed in the suspension obtained by ultrasonic treatment of cocoa-derived pulp for 4 minutes, indicating good dispersion. In contrast, most of the sample obtained by ultrasonic treatment of cedar sulfate (KP) pulp precipitated, and no dispersibility was confirmed. These results suggest that cellulose in cocoa-derived pulp is more readily nanofiberized by ultrasonic treatment compared to cellulose in cedar-derived pulp.

[0241] It should be noted that, Figure 8 The line representing the Ca48-US4m sample overlaps with the line representing the Ca50-US4m sample, but both show 100cc at any given time.

[0242] 7-2: Study on the sedimentation rate after 1 minute of ultrasonic treatment (from cocoa bean husk pulp)

[0243] In addition, 0.1 g (by dry weight) of cocoa-derived pulp (Ca48, Ca50, Ca51) obtained from cocoa bean shells was mixed with distilled water to prepare 100 mL of 0.1 wt% suspension. The suspension was then treated with an ultrasonic homogenizer for 1 minute under the test conditions shown in Table 14, and the test was carried out in the same manner as in 7-1.

[0244] [Table 14]

[0245]

[0246] The results are as follows Figure 9 As shown.

[0247] Here, Figure 9 The graph shows the time-varying sedimentation level of suspension samples obtained by ultrasonic treatment (Ca48, Ca50, Ca51) derived from cocoa pulp (Ca48, Ca50, Ca51) for 1 minute.

[0248] for Figure 9 The samples (Ca48, Ca50, Ca51: ultrasonically treated for 1 minute), despite the short ultrasonic treatment time, showed better performance than... Figure 8 Compared to the above-mentioned samples derived from cedar trees that underwent ultrasonic treatment (4 minutes of ultrasonic treatment), no sedimentation was observed, confirming good dispersion and stabilization.

[0249] It should be noted that, Figure 10 Photographs of ultrasonically treated samples (Ca48, Ca50, Ca51: 1 minute ultrasonic treatment) derived from cocoa pulp at 1 hour and 5 hours after the start of the test.

[0250] 7-3: Study on sedimentation rate after 4 minutes of ultrasonic treatment (from cocoa pod pulp)

[0251] In addition, cocoa-derived pulp (Ca43~47) obtained from cocoa pods was used, and the experiment was conducted under the conditions in Table 15 according to 7-1.

[0252] The results are as follows Figure 11 As shown.

[0253] Figure 11In the figure, the lines representing Ca44~47 overlap, but both show 100cc at any given time. That is, Ca44~47 are well dispersed, and no sedimentation was observed in the suspension. Although some sedimentation was observed in Ca43, even after 70 hours, the sedimentation rate (scale) still showed above 90cc, indicating that CNF was well dispersed and stabilized.

[0254] It should be noted that even at a concentration of 0.1 wt%, Ca44~47 exhibit significant gelation, especially Ca46, which becomes a fairly hard gel, while Ca45 increases in hardness over time.

[0255] Example 8: Viscosity determination of CNF derived from cocoa pulp

[0256] The viscosity of CNF obtained from cocoa pulp was determined (n=3) under the conditions described in Table 15.

[0257] [Table 15]

[0258]

[0259] The results are shown in Table 16.

[0260] [Table 16]

[0261]

[0262] In addition, as a reference area, the viscosity of CNF obtained from cedar pulp and CNF from cedar were measured under the conditions described in Table 17 (n=3).

[0263] [Table 17]

[0264]

[0265] The results are shown in Table 18.

[0266] Here, "TEMPO oxidation" refers to chemical treatment using TEMPO as described in Saito T, Nishiyama Y., Putaux J.-L., Vignon M., Isoga A. Homogeneous Suspensions of Individualized Microfibrils from TEMPO-Catalyzed Oxidation of Native Cellulose. Biomacromolecules 2006, 7, 1687-1691.

[0267] "10-time water jet treatment" refers to a mechanical treatment performed 10 times using a high-pressure homogenizer (Sugino Machine Co., Ltd., machine name Star Burst 100).

[0268] [Table 18]

[0269]

[0270] Example 9: Manufacturing of CNF films derived from cocoa pulp

[0271] 9-1

[0272] 0.1 g (dry weight) of unbleached cocoa-derived pulp obtained from cocoa bean shells was mixed with distilled water to prepare 100 mL of a 0.1 wt% suspension. The suspension was then treated with an ultrasonic homogenizer under the experimental conditions shown in Table 19, and the experiment was conducted in the same manner as in 7-1 to obtain CNF films (n=5). The properties of the obtained films were evaluated by trained judges (n=3).

[0273] The results are shown in Table 19.

[0274] [Table 19]

[0275]

[0276] CNF films derived from cocoa pulp were found to be soft and not easily broken even under pressure. On the other hand, CNF films made from other raw materials (cedar) using the same method as described above, though not shown in the table, were brittle and hard to the touch and easily torn.

[0277] 9-2

[0278] 0.1 g (dry weight) of unbleached cocoa-derived pulp obtained from cocoa bean shells was mixed with distilled water to prepare a 0.1 wt% suspension of 100 mL. The suspension was then treated with an ultrasonic homogenizer under the experimental conditions shown in Table 20, and the experiment was conducted in the same manner as in 7-1 to obtain CNF films (n=5). The properties of the obtained films were evaluated by trained judges (n=3).

[0279] The results are shown in Table 20 and Figure 12 As shown.

[0280] [Table 20]

[0281]

[0282] CNF films with a NaOH concentration of 2 (w / w%) were obtained compared to those with a concentration of 5 (w / w%). It should be noted that in the above experiments, a well-dispersed suspension was obtained in the first 2 minutes of the treatment at 80°C (ultrasonic treatment), but agglomeration was observed in the first 2 minutes of the treatment at 140°C, therefore an additional 2 minutes of treatment was performed.

Claims

1. A method for producing cocoa-derived pulp, comprising: The process of evaporating cocoa-derived raw materials using an alkaline solution.

2. The method according to claim 1, wherein, The cocoa-derived raw material is cocoa bean shell or cocoa pod.

3. The method according to claim 1, wherein, The temperature of the alkaline solution is above 80°C and below 140°C.

4. The method according to claim 1, wherein, The concentration of the alkali in the alkaline solution is above 1 w / w% and below 8 w / w%.

5. The method according to claim 1, wherein, The evaporation time is within 3 hours.

6. A cocoa pulp that satisfies at least one of the following (A) to (C): (A) The proportion of fibers with a length of 100µm or more relative to the total number of fibers is 50% or more; (B) The proportion of fibers with a length of 250µm or more is 30% or more relative to the number of fibers other than those derived from soft cells. (C) The cellulose crystallinity is above 40%.

7. The cocoa-derived pulp according to claim 6, wherein, In (A), the proportion of fibers with a length of 200µm or more relative to the total number of fibers is 35% or more.

8. The cocoa-derived pulp according to claim 6, wherein, The total fiber number is the sum of fibers derived from soft cells, vascular bundle cells, and fiber cells.

9. The cocoa-derived pulp according to claim 6, wherein, The proportion of fibers with a length of 450µm or more is more than 40% relative to the number of fibers other than those derived from soft cells.

10. The cocoa-derived pulp according to claim 6, wherein, In the following methods for determining settling velocity, the graduated cylinder used as the indicator of settling velocity, JIS R3505, must have a graduation of 80 cc or higher at 72 hours. The sedimentation rate determination method is as follows: 100 mL of a 0.1 w / w% mixture obtained by adding distilled water to 0.1 g of cocoa pulp (dry weight) is treated with an ultrasonic homogenizer for 4 minutes to obtain a 0.1 w / w% suspension. Then, the suspension is injected into a 100 mL volumetric cylinder and allowed to stand. The upper limit of the sedimentation rate of the cocoa pulp is measured at regular intervals.

11. The cocoa-derived pulp according to claim 6, obtained by the method of claim 1.

12. A method for manufacturing cellulose nanofibers derived from cocoa, comprising: The process of defiberizing pulp derived from cocoa.

13. The method according to claim 12, wherein, The cocoa-derived pulp is obtained by the method of claim 1.

14. The method according to claim 12, wherein, The fiber disassembly process is carried out using ultrasonic treatment.

15. A cellulose nanofiber derived from cocoa, which satisfies at least one of the following (D) to (H): (D) The proportion of fibers with a length of more than 1000 nm in the cellulose nanofibers derived from cocoa is more than 40%. (E) The proportion of fibers with a fiber width of less than 5 nm in the cocoa-derived cellulose nanofibers is more than 50%. (F) The average aspect ratio is 200 or higher; (G) The crystallinity of cellulose is above 40%; (H) The viscosity of the 1 w / w% aqueous suspension of cellulose nanofibers derived from cocoa is above 900 mPa·s.

16. The cocoa-derived cellulose nanofibers according to claim 15, wherein, In (D), the proportion of fibers with a length of more than 2000 nm in the cocoa-derived cellulose nanofibers is more than 50%.

17. The cocoa-derived cellulose nanofibers according to claim 15, wherein, In the following methods for determining settling velocity, the graduated cylinder used as the indicator of settling velocity, JIS R3505, must have a graduation of 80 cc or higher at 72 hours. The sedimentation rate determination method is as follows: 100 mL of 0.1 w / w% aqueous suspension is obtained by adding distilled water to 0.1 g of cocoa-derived cellulose nanofibers (dry weight). The suspension is then injected into a 100 mL volumetric cylinder and allowed to stand. The upper limit of the sedimentation rate of the cocoa-derived cellulose nanofibers is measured at intervals of time.

18. The cocoa-derived cellulose nanofibers according to claim 15, wherein, In (H), the viscosity is below 1500 mPa·s.

19. The cocoa-derived cellulose nanofibers according to claim 15, obtained by the method of claim 12 or 13.

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