Method for deodorizing materials derived from marine microalgae, and method for manufacturing products containing materials derived from marine microalgae

Abstract

This invention provides a method for deodorizing marine microalgae-derived materials, and a method for producing products containing marine microalgae-derived materials, which allows for easy deodorization of marine microalgae-derived materials and minimizes the residue of compounds used in the deodorization process on the marine microalgae-derived materials. [Solution] A method for deodorizing a marine microalgae-derived material, comprising the step (A) of treating the marine microalgae-derived material with a volatile alkaline compound. A method for producing a marine microalgae-derived material-containing product, comprising the step (a) of deodorizing the marine microalgae-derived material using the method for deodorizing the marine microalgae-derived material, and the step (b) of mixing the marine microalgae-derived material deodorized in step (a) with at least one other material.

Description

Technical Field

[0001] The present invention relates to a method for deodorizing a marine microalgae-derived material, and a method for producing a product containing a marine microalgae-derived material.

Background Art

[0002] Marine microalgae can produce biomass through photosynthesis, and can be easily propagated using seawater or the like. Therefore, they are expected to be used in various applications as biomass materials with low environmental impact. In addition, since some marine microalgae produce various useful components, they can also be utilized for the production of such useful components. Residues obtained after extracting target useful components from marine microalgae can also be utilized as biomass materials.

[0003] However, marine microalgae have a characteristic odor, and the odor may remain in final products manufactured using marine microalgae-derived materials. For this reason, methods for deodorizing marine microalgae-derived materials are being investigated.

[0004] For example, Patent Document 1 describes deodorizing algal cells by subjecting them to acid washing and sodium hydroxide treatment.

[0005] For example, Patent Document 2 describes a method for deodorizing Nannochloropsis algal biomass by bringing the Nannochloropsis algal biomass into contact with an adduct-forming compound selected from metal sulfites, metal bisulfites, ammonium bisulfite, metal metabisulfites, SO₂, or mixtures thereof.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

[0007] However, the methods described in Patent Documents 1 and 2 make it difficult to remove the compounds used in the deodorization treatment from materials derived from marine microalgae.

[0008] Therefore, the object of this disclosure is to provide a method for deodorizing marine microalgae-derived materials, and a method for producing products containing marine microalgae-derived materials, which allows for easy deodorization of marine microalgae-derived materials and minimizes the residue of compounds used in the deodorization process on the marine microalgae-derived materials. [Means for solving the problem]

[0009] The present invention includes the following embodiments. [1] A method for deodorizing a material derived from marine microalgae, comprising step (A) of treating the material with a volatile alkaline compound. [2] The method for deodorizing marine microalgae-derived materials according to [1], wherein the volatile alkali compound is a compound with a boiling point of 10°C or lower. [3] The method for deodorizing a marine microalgae-derived material according to [1], wherein the volatile alkali compound is ammonia. [4] A method for deodorizing a marine microalgae-derived material according to any one of [1] to [3], further comprising a step (B) of volatilizing the volatile alkali compound and dimethyl sulfide after step (A). A method for producing a product containing marine microalgae, comprising: (a) a step of deodorizing a marine microalgae-derived material using a method for deodorizing marine microalgae-derived materials described in any one of [5][1] to [4]; and (b) a step of mixing the marine microalgae-derived material deodorized in step (a) with at least one other material. [6] The method for producing a marine microalgae-derived material-containing product according to [5], wherein the marine microalgae-derived material-containing product is a plastic product, and the at least one other material includes a plastic resin. [Effects of the Invention]

[0010] This disclosure provides a method for deodorizing marine microalgae-derived materials, and a method for producing products containing marine microalgae-derived materials, which allows for easy deodorization of marine microalgae-derived materials and minimizes the residue of compounds used in the deodorization process on the marine microalgae-derived materials. [Modes for carrying out the invention]

[0011] The embodiments of the present invention will be described in detail below, but the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of the invention. Furthermore, if multiple upper and lower limits are given for a particular parameter, any combination of these upper and lower limits can be used to create a suitable numerical range. A numerical range represented using "~" means a range that includes the numbers written before and after "~" as the lower and upper limits.

[0012] [Deodorization method for materials derived from marine microalgae] A first aspect of this disclosure is a method for deodorizing a material derived from marine microalgae. The deodorizing method includes a step (A) of treating the material derived from marine microalgae with a volatile alkali compound.

[0013] <Process (A)> (marine microalgae) "Marine microalgae" refers to microalgae that inhabit the sea. "Microalgae" refers to eukaryotic algae and cyanobacteria that are too small to be seen with the naked eye. Microalgae, for example, are less than 1000 μm in size.

[0014] Marine microalgae are not particularly limited. Examples of marine microalgae include, but are not limited to, diatoms, green algae, red algae, dinoflagellates, cryptophytes, haptophytes, etc. Examples of marine microalgae include algae of the genera Chlamydomonas, Chlorella, Dunaliella, Nannochloropsis, Botryococcus, Chaetoceros, Chlorecoccum, Euglena, Haematococcus, Isocrysis Examples include, but are not limited to, algae of the genera Isochrysis, Navicula, Neochloris, Porphyridium, Prymnesium, Scenedes, Spirulina, Spirogyra, Synechoccus, and Tetraselmis. Marine microalgae containing dimethyl sulfoniopropionate (DMSP) are preferred.

[0015] (Materials derived from marine microalgae) "Marine microalgae-derived material" refers to a material containing components derived from marine microalgae. Marine microalgae-derived material may contain cells or parts of cells of marine microalgae. Marine microalgae-derived material may also be a cellular residue from which at least one component has been extracted from marine microalgae.

[0016] The material derived from marine microalgae may be a dried product or a wet product, with a dried product being preferred. From the viewpoint of the efficiency of the treatment with a volatile alkali compound described later, the material derived from marine microalgae is preferably a dry powder. When the material derived from marine microalgae is a dry powder, the dry powder can be obtained, for example, by drying cells or cell residues of marine microalgae and then pulverizing them. As the drying method, a known method can be used, and examples thereof include freeze drying, vacuum drying, heat drying and the like. As the pulverization method, a known method can be used, and examples thereof include a method of pulverizing using a mortar and pestle, and a method of pulverizing using a cell pulverizer or the like.

[0017] The material derived from marine microalgae may be a cell residue obtained after subjecting marine microalgae to organic solvent extraction (for example, ethanol extraction). The cell residue may be a wet product or a dried product.

[0018] (Volatile alkali compound) The "volatile alkali compound" refers to an alkali compound that is volatile at normal temperature (for example, 20°C). Examples of the volatile alkali compound include alkali compounds having a boiling point of 10°C or lower, a boiling point of 5°C or lower, or a boiling point of 0°C or lower. The "alkali compound" refers to a compound that exhibits basicity when dissolved in water. Specific examples of the volatile alkali compound include ammonia.

[0019] By using a volatile alkali compound, the volatile alkali compound can be easily removed after the alkali treatment.

[0020] (Treatment with volatile alkali compound) The treatment of a marine microalgae-derived material with a volatile alkali compound can be carried out by bringing the volatile alkali compound into contact with the marine microalgae-derived material. For example, the treatment with the volatile alkali compound can be performed by adding an aqueous solution of the volatile alkali compound (e.g., a 5 to 30 mass% aqueous solution) to the marine microalgae-derived material and stirring the resulting mixture. When the marine microalgae-derived material is a dried product, water may be added to the marine microalgae-derived material to moisten the marine microalgae-derived material before adding the aqueous solution of the volatile alkali compound. When the volatile alkali compound is ammonia, the treatment can be carried out by adding aqueous ammonia to the marine microalgae-derived material. As the aqueous ammonia, for example, 10 to 30 mass% aqueous ammonia can be used. The usage amount of the aqueous solution of the volatile alkali compound may be an amount sufficient to immerse the entire marine microalgae-derived material. The usage amount of the aqueous solution of the volatile alkali compound may be an amount sufficient to suspend the entire marine microalgae-derived material and allow the resulting suspension to be stirred.

[0021] When aqueous ammonia is used, the concentration of ammonia in the mixture of the marine microalgae-derived material and aqueous ammonia includes, for example, 0.1 to 20 mass%. The concentration of ammonia may be 0.2 mass% or more, 0.5 mass% or more, 0.6 mass% or more, 0.7 mass% or more, 1 mass% or more, 1.5 mass% or more, 2 mass% or more, or 2.5 mass% or more. The concentration of ammonia may be 15 mass% or less, 15 mass% or less, 10 mass% or less, 8 mass% or less, 7 mass% or less, or 6 mass% or less.

[0022] When stirring is performed, the stirring speed includes, for example, 100 to 500 rpm, but is not limited thereto. The treatment temperature includes, for example, 10 to 60°C or 10 to 30°C, but is not limited thereto. The treatment can be carried out, for example, under atmospheric pressure (1 atm, 1013 hPa), but is not limited thereto. The processing time is not particularly limited and can be appropriately selected depending on the amount of marine microalgae-derived material. Examples of processing times include 1 minute or more, 2 minutes or more, 3 minutes or more, 4 minutes or more, or 5 minutes or more. Examples of processing times include 1 to 60 minutes, 2 to 30 minutes, 3 to 30 minutes, 4 to 30 minutes, or 5 to 30 minutes, but are not limited to these.

[0023] Alternatively, the material may be treated at 50-90°C (preferably 50-70°C) under atmospheric pressure, followed by drying under vacuum conditions at 50-90°C (preferably 50-70°C). The treatment time at 50-90°C under atmospheric pressure may be, for example, 30 minutes or more, 40 minutes or more, 50 minutes or more, or 60 minutes or more. The treatment time at 50-90°C under atmospheric pressure may be, for example, 240 minutes or less, 180 minutes or less, 150 minutes or more, 120 minutes or more, 90 minutes or more, or 60 minutes or less. The treatment time at 50-90°C under vacuum conditions may be 30 minutes or more, 40 minutes or more, 50 minutes or more, 60 minutes or more, 90 minutes or more, or 120 minutes or more. The treatment time at 50-90°C under vacuum conditions may be, for example, 360 minutes or less, 300 minutes or less, 240 minutes or less, 180 minutes or less, 150 minutes or more, or 120 minutes or more.

[0024] Alternatively, the material derived from marine microalgae may be treated with a volatile alkali compound by filling a sealed container containing the material with a gas of the volatile alkali compound.

[0025] By treating marine microalgae-derived materials with volatile alkaline compounds, DMSP contained in the materials can be converted to dimethyl sulfide (DMS). DMSP and DMS are substances that cause odor in marine microalgae-derived materials. Because DMS is more volatile than DMSP, it can be easily removed from marine microalgae-derived materials by heat treatment or vacuum treatment. In addition, volatile alkaline compounds can also be removed along with DMS by heat treatment or vacuum treatment.

[0026] <Other processes> The deodorization method of this embodiment may include other steps in addition to step (a) described above. Examples of other steps include step (B) of volatilizing a volatile alkali compound and dimethyl sulfide.

[0027] (Process (B)) Step (B) can be performed after step (A). In step (B), the volatile alkali compound used in step (A) and the dimethyl sulfide generated in step (A) are volatilized and removed from the marine microalgae-derived material. The volatilization method is not particularly limited, and known methods can be used. Examples of volatilization methods include volatilization by heating and volatilization by reduced pressure.

[0028] When volatilization is performed by heating, for example, the mixture obtained in step (A) may be spread thinly on a tray or plate and then heated. Spreading it thinly can improve the volatilization efficiency. Examples of heating temperatures include 50 to 80°C, preferably 60 to 70°C. Examples of heating times include 30 minutes or more, 40 minutes or more, 50 minutes or more, and 60 minutes or more. Examples of upper limits for heating time include 180 minutes or less, 150 minutes or less, 120 minutes or less, and 90 minutes or less. Examples of heating times include 30 to 180 minutes, 40 to 150 minutes, 50 to 90 minutes, 60 to 90 minutes, etc., but are not limited to these. The heating time should be sufficient to remove the volatile alkali compound and dimethyl sulfide from the mixture obtained in step (A).

[0029] When volatilization is performed by reducing pressure, for example, an evaporator can be used.

[0030] The marine microalgae-derived material after step (B) is usually dry. The dried material obtained in step (B) may be pulverized to obtain a dry powder.

[0031] In the deodorization method according to this embodiment, DMSP contained in marine microalgae-derived material is converted to DMS using a volatile alkaline compound. DMSP and DMS are substances that cause odor in marine microalgae-derived material, and it is believed that their presence causes odor in the final product containing marine microalgae-derived material. In the deodorization method according to this embodiment, DMSP and DMS can be removed from marine microalgae-derived material by converting DMSP to the more volatile DMS and volatilizing it. In addition, volatile alkaline compounds can also be removed by volatilization along with DMS. Therefore, deodorization treatment of marine microalgae-derived material can be performed without leaving any residual volatile alkaline compounds used in the treatment.

[0032] The marine microalgae-derived material obtained by the deodorization method according to this embodiment can be processed into various products. The marine microalgae-derived material may be used as is or mixed with other materials. The marine microalgae-derived material can be used in various fields, such as the food and beverage sector, cosmetics sector, pharmaceutical and healthcare sector, biomaterials and industrial sector, environmental technology and agriculture sector, livestock farming and aquaculture sector, etc.

[0033] In the food and beverage sector, marine microalgae-derived materials may be incorporated into foods, beverages, etc., to create food or beverage products. Marine microalgae-derived materials can be used, for example, in processed foods, functional foods, powdered smoothies, instant foods, confectionery, sweets, etc. Alternatively, they may be used as additives such as colorants, seasonings, and flavorings.

[0034] In the cosmetics field, materials derived from marine microalgae may be incorporated into cosmetics, skincare products, etc., to create cosmetics or skincare products. For example, the functions of various components contained in materials derived from marine microalgae can be utilized. Materials derived from marine microalgae can be incorporated into cosmetics, skincare products, body care products, bath additives, sunscreens, etc., as antioxidants, anti-inflammatory agents, UV protectants, exfoliants, antibacterial agents, deodorants, etc.

[0035] In the pharmaceutical and healthcare fields, marine microalgae-derived materials may be incorporated into pharmaceuticals and healthcare products. For example, the functions of various components contained in marine microalgae-derived materials can be utilized. Marine microalgae-derived materials can be incorporated into herbal medicines, supplements, pharmaceuticals, etc., as anti-inflammatory agents, antioxidants, antibacterial agents, dietary fiber, etc.

[0036] In the biomaterials and industrial fields, marine microalgae-derived materials can be incorporated into various industrial products. Marine microalgae-derived materials can be used, for example, in plastics, paper products, film products, functional fibers, paints, coatings, and the like.

[0037] In the fields of environmental technology and agriculture, materials derived from marine microalgae may be incorporated into soil conditioners, water purifiers, biofuels, etc., to create soil conditioners, water purifiers, and biofuels.

[0038] In the livestock and aquaculture sectors, marine microalgae-derived materials may be incorporated into feeds and animal feed as additives or nutrients. For example, the functions of various components contained in marine microalgae-derived materials can be utilized.

[0039] [Manufacturing method for products containing materials derived from marine microalgae] A second aspect of this disclosure is a method for producing a product containing a material derived from marine microalgae. The production method includes (a) a step of deodorizing a material derived from marine microalgae using a method for deodorizing a material derived from marine microalgae according to the first aspect, and (b) a step of mixing the material derived from marine microalgae that has been deodorized in step (a) with at least one other material.

[0040] <Process (a)> Step (a) is a step of deodorizing a marine microalgae-derived material using the deodorization method for marine microalgae-derived materials according to the first embodiment described above. Step (a) can be carried out in the same manner as the method described in the section [Deodorization Method for Marine Microalgae-Derived Materials] above.

[0041] Step (b) is a step of mixing the marine microalgae-derived material, which has been deodorized in step (a), with at least one other material.

[0042] Products containing materials derived from marine microalgae are not particularly limited. Examples of products containing materials derived from marine microalgae include the various products exemplified in the section [Deodorization Method for Materials Derived from Marine Microalgae] above.

[0043] At least one other material may be appropriately selected depending on the type of product containing marine microalgae-derived materials. For example, when manufacturing food or beverages, marine microalgae-derived materials can be mixed with food or beverage ingredients. For example, when manufacturing cosmetics or skincare products, marine microalgae-derived materials can be mixed with cosmetic or skincare product ingredients. For example, when manufacturing pharmaceuticals or healthcare products, marine microalgae-derived materials can be mixed with pharmaceutical or healthcare product ingredients. For example, when manufacturing industrial products, marine microalgae-derived materials can be mixed with industrial product ingredients. For example, when manufacturing agricultural products or environmental technology products, marine microalgae-derived materials can be mixed with agricultural or environmental technology product ingredients. For example, when manufacturing livestock products or aquaculture products, marine microalgae-derived materials can be mixed with livestock products or aquaculture product ingredients.

[0044] For example, a product containing materials derived from marine microalgae is a plastic product, and at least one other material may also contain a plastic resin. "Plastic resin" refers to a resin used in the manufacture of plastic products. Examples of plastic resins include, but are not limited to, polyethylene, polypropylene, polyurethane, polyester, polyvinyl chloride, acrylic resin, polycarbonate, polyamide, polyacetal, polybutylene terephthalate, polysulfone, polyamide, phenolic resin, epoxy resin, melamine resin, polylactic acid, and cellulose acetate resin.

[0045] Plastic products containing materials derived from marine microalgae can be manufactured, for example, by mixing powdered plastic resin with dried powdered marine microalgae-derived material, stirring until uniform, heating, and then molding the mixture into a plastic product. The mass ratio when mixing the plastic resin and the marine microalgae-derived material (plastic resin: marine microalgae-derived material) is not particularly limited, but examples include 30:70 to 90:10.

[0046] By using a marine microalgae-derived material obtained by the deodorization method for marine microalgae-derived materials according to the first embodiment, it is possible to manufacture a marine microalgae-derived material-containing product that does not emit an unpleasant odor. [Examples]

[0047] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0048] <Deodorization using marine microalgae (1)> Dried algal powder was obtained by freeze-drying the algal bodies of the marine microalga (Chaetoseros gracilis). The deodorization treatment for the examples and comparative examples was performed according to the following procedure.

[0049] (Example 1) (1) 30 g of dried algal powder was mixed with 30 mL of deionized water and stirred. (2) 20 mL of 10% by mass ammonia water was added to the paste-like algal material and stirred at room temperature for 5 minutes. (3) The paste-like algal material obtained in (2) was spread thinly on a metal tray and heated at 60°C for 1 hour to dry and remove ammonia. (4) The dried algal material was collected, crushed in a mortar, and then subjected to a sensory evaluation.

[0050] (Comparative Example 1) (1) 30 g of dried algal powder was mixed with 30 mL of deionized water and stirred. (2) Add 20 mL of deionized water to the paste-like algal material and stir at room temperature for 5 minutes. (3) The paste-like algal material obtained in (2) was spread thinly on a metal tray and heated at 60°C for 1 hour to dry. (4) The dried algal material was collected, crushed in a mortar, and then subjected to a sensory evaluation.

[0051] <Sensory Testing> (1) 5 g of the pulverized algae from the example was weighed, placed in a screw-top test tube (glass), and left at room temperature for 5 minutes. Similarly, 5 g of the pulverized algae from the comparative example was weighed, placed in a screw-top test tube (glass), and left at room temperature for 5 minutes. (2) Five testers smelled each screw-top test tube and evaluated the odor.

[0052] The results are shown in Table 1. The results shown in Table 1 were evaluated according to the following criteria. (Smell of the sea) A: A faint, unpleasant smell of the sea. B: A strong, unpleasant smell of the sea.

[0053] (Sulfurous, putrid smell) A: There is no sulfurous, putrid smell. B: It has a sulfurous, putrid smell.

[0054] (Ammonia smell) A: There is no ammonia smell. B: It smells like ammonia.

[0055] [Table 1]

[0056] As shown in Table 1, the examples showed a significant reduction in both the sea odor and the sulfurous, putrid odor compared to the comparative example. This result confirms that ammonia treatment reduces odor. Furthermore, a faint, sweet scent reminiscent of matcha green tea was detected in the examples.

[0057] <Deodorization using marine microalgae (2)> Ethanol extraction was performed on the thallus of the marine microalga (Chaetoseros gracilis), and the extraction residue of the thallus was obtained. The deodorization treatments for Examples 2-6 and Comparative Example 2 were carried out according to the following procedure.

[0058] (Examples 2-6) (1) The extraction residue and 28% by mass ammonia water were mixed in the mixing ratios shown in Table 2 below.

[0059] [Table 2]

[0060] (2) After mixing, the mixture was heated in a 60°C incubator for 1 hour to allow it to react, and then dried in a vacuum dryer at 60°C under vacuum conditions for 2 hours. The dried algal material was in the form of a film. (3) The dried algal material was collected, crushed in a mortar, and then subjected to a sensory evaluation.

[0061] (Comparative Example 2) (1) The extracted residue was heated in a 60°C incubator for 1 hour to react, and then dried in a vacuum dryer at 60°C under vacuum conditions for 2 hours. The thallus after drying was in the form of a film. (2) The dried algal material was collected, crushed in a mortar, and then subjected to a sensory evaluation.

[0062] <Sensory Testing> (1) 5 g of the pulverized algae from the example was weighed, placed in a screw-top test tube (glass), and left at room temperature for 5 minutes. Similarly, 5 g of the pulverized algae from the comparative example was weighed, placed in a screw-top test tube (glass), and left at room temperature for 5 minutes. (2) Five testers smelled each screw-top test tube and evaluated the odor. "0" was used to indicate no odor, and the intensity of the odor was evaluated on a 5-point scale.

[0063] The results are shown in Table 3. A higher number indicates a stronger odor.

[0064] [Table 3]

[0065] In Examples 3 to 6, it was confirmed that the odor intensity was reduced compared to Comparative Example 2.

[0066] Table 4 shows the ammonia concentrations in the mixture of marine microalgae and ammonia water during ammonia treatment for Examples 1-6 and Comparative Examples 1 and 2.

[0067] [Table 4] [Industrial applicability]

[0068] The present invention provides a method for deodorizing marine microalgae-derived materials, and a method for producing products containing marine microalgae-derived materials, which allows for easy deodorization of marine microalgae-derived materials and minimizes the residue of compounds used in the deodorization process on the marine microalgae-derived materials.

Claims

1. A method for deodorizing a material derived from marine microalgae, comprising step (A) of treating the material with a volatile alkaline compound.

2. The method for deodorizing a marine microalgae-derived material according to claim 1, wherein the volatile alkali compound is a compound with a boiling point of 10°C or lower.

3. The method for deodorizing a marine microalgae-derived material according to claim 1, wherein the volatile alkaline compound is ammonia.

4. A method for deodorizing a marine microalgae-derived material according to claim 1, further comprising a step (B) of volatilizing the volatile alkali compound and dimethyl sulfide after the above step (A).

5. A step (a) of deodorizing a marine microalgae-derived material using the deodorization method for marine microalgae-derived materials described in any one of claims 1 to 4, Step (b) involves mixing the marine microalgae-derived material, which has been deodorized in step (a), with at least one other material. A method for producing a product containing marine microalgae-derived materials, including [the specified material].

6. The method for producing a marine microalgae-derived material-containing product according to claim 5, wherein the marine microalgae-derived material-containing product is a plastic product, and the at least one other material includes a plastic resin.

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