Method for producing earthworm powder

Abstract

The objective is to provide a method for efficiently producing earthworm powder that reduces the characteristic odor of earthworms and can be used directly as a protein source in food products. [Solution] A method for producing earthworm powder, comprising: a filth removal process to remove any remaining filth inside the body of the earthworm to be powdered; a body fluid discharge process to discharge body fluid from the earthworm; a sterilization process to kill the earthworm; a drying process to dry the earthworm; and a powdering process to turn the dried earthworm into powder, wherein the sterilization process is either a hot air heating process in which the earthworm from which the filth has been removed is heated with hot air at 150°C or higher, or a boiling process in which the earthworm from which the filth has been removed is boiled in water.

Description

Technical Field

[0001] The present invention relates to a method for producing earthworm powder.

Background Art

[0002] As the problem of food shortage due to the global population increase becomes more serious, with the economic development of emerging countries, people who have been obtaining energy from carbohydrates such as rice and bread have come to consume more protein such as meat and seafood. It is said that in the near future, the balance between the supply and demand of protein will be disrupted, and a "protein crisis" will occur globally where protein is in short supply.

[0003] However, at present, measures relying on the increased production of livestock and fishery resources lack sustainability and are not practical. Therefore, as one of the countermeasures for food demand that does not depend on these livestock and fishery resources, the development of alternative proteins is being promoted in various countries around the world.

[0004] Under such circumstances, the applicant of the present application has focused on earthworms, which are rich in protein, highly nutritious, distributed in various countries around the world, and easily available, and has decided to develop earthworm powder as a food suitable for alternative proteins.

[0005] Regarding this earthworm powder, for example, a production method as shown in the following patent document (hereinafter referred to as the "conventional method") has been proposed. However, the earthworm powder produced by the conventional method has a peculiar smell of earthworms and is difficult to be directly applied to food as a protein source. In addition, many processes such as the removal of feces and coelomic fluid in the body, sterilization, drying, and powdering are required, so the production is complicated and the production efficiency is not good.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] The present invention aims to solve the problems of such conventional methods and to provide a method for efficiently producing earthworm powder that has a reduced earthworm-specific odor and can be used directly as a protein source in food. [Means for solving the problem]

[0008] The gist of the present invention will be explained with reference to the attached drawings.

[0009] The present invention relates to a method for producing earthworm powder, comprising a filth removal treatment to remove any remaining filth from the body of the earthworm to be powdered, a body fluid discharge treatment to discharge body fluid from the earthworm, a sterilization treatment to kill the earthworm, a drying treatment to dry the earthworm, and a powdering treatment to turn the dried earthworm into powder, wherein the sterilization treatment is either a hot air heating treatment in which the earthworm from which the filth has been removed is heated with hot air at 150°C or higher, or a boiling treatment in which the earthworm from which the filth has been removed is boiled in water.

[0010] Furthermore, the present invention relates to a method for producing earthworm powder according to claim 1, characterized in that the sterilization treatment and the drying treatment are performed simultaneously by the hot air heating treatment.

[0011] Furthermore, the method for producing earthworm powder according to claim 2 is characterized in that the hot air heating treatment is performed at a hot air temperature of 180°C ± 10°C and a treatment time of 15 minutes ± 5 minutes.

[0012] Furthermore, the method for producing earthworm powder according to claim 2 is characterized in that the body cavity fluid drainage treatment is a treatment in which the earthworms are immersed in an alkaline solution.

[0013] Furthermore, the method for producing earthworm powder according to claim 3 is characterized in that the body cavity fluid drainage treatment is a treatment in which the earthworms are immersed in an alkaline solution.

[0014] Furthermore, the method for producing earthworm powder according to claim 4 is characterized in that the body cavity fluid drainage treatment is a process in which the earthworms are alternately subjected to an immersion treatment in which they are submerged in the alkaline solution and a pure water washing treatment in which they are washed with pure water, and this process is repeated multiple times.

[0015] Furthermore, the method for producing earthworm powder according to claim 5 is characterized in that the body cavity fluid drainage treatment is a process in which the earthworms are repeatedly and alternately subjected to an immersion treatment in which they are submerged in the alkaline solution and a pure water washing treatment in which they are washed with pure water.

[0016] Furthermore, the present invention relates to a method for producing earthworm powder according to claim 1, characterized in that the body cavity fluid removal treatment and the sterilization treatment are performed simultaneously by the boiling treatment.

[0017] Furthermore, the method for producing earthworm powder according to claim 8 is characterized in that the boiling treatment is a process of placing earthworms and water in a container, heating the water, and boiling it for 1 minute or more.

[0018] Furthermore, the method for producing earthworm powder according to claim 8 is characterized in that the drying treatment is freeze-drying or hot air heating.

[0019] Furthermore, the method for producing earthworm powder according to claim 9 is characterized in that the drying treatment is freeze-drying or hot air heating.

[0020] Also, in the method for producing earthworm powder according to any one of claims 1 to 11, the manure removal treatment is a treatment in which the earthworms are starved while supplying air in water, and it relates to a method for producing earthworm powder.

[0021] Also, in the method for producing earthworm powder according to claim 12, the water is tap water from which calcium has been removed, and it relates to a method for producing earthworm powder.

[0022] Also, in the method for producing earthworm powder according to any one of claims 1 to 11, the earthworms are any one of Eisenia andrei, Eisenia fetida, Lumbricus rubellus, Lumbricus terrestris, Drawida hattamimizu, Pheretima sp., Perionyx excavatus, and Eudrilus eugeniae, and it relates to a method for producing earthworm powder.

[0023] Also, in the method for producing earthworm powder according to claim 12, the earthworms are any one of Eisenia andrei, Eisenia fetida, Lumbricus rubellus, Lumbricus terrestris, Drawida hattamimizu, Pheretima sp., Perionyx excavatus, and Eudrilus eugeniae, and it relates to a method for producing earthworm powder.

[0024] Also, in the method for producing earthworm powder according to claim 13, the earthworms are any one of Eisenia andrei, Eisenia fetida, Lumbricus rubellus, Lumbricus terrestris, Drawida hattamimizu, Pheretima sp., Perionyx excavatus, and Eudrilus eugeniae, and it relates to a method for producing earthworm powder.

Advantages of the Invention

[0025] Since the present invention is configured as described above, it is possible to efficiently produce earthworm powder with a reduced earthworm-specific odor and which can be directly applied as a protein source to food. Thus, it becomes a method for producing earthworm powder.

Brief Description of the Drawings

[0026] [Figure 1] This is a process flow diagram of the present embodiment, where (a) shows the case where boiling treatment is selected for sterilization treatment, and (b) shows the case where hot air heating treatment is selected for sterilization treatment. [Figure 2] This is a photograph showing the color of the liquid after the body cavity fluid drainage treatment in Experiment 1. [Figure 3] This is a photograph showing the color of the liquid after the body cavity fluid drainage treatment in Experiment 2. [Figure 4] This is a photograph showing the color of the liquid after the body cavity fluid drainage treatment in Experiment 3. <00,001,07> [Figure 5] This is a graph showing the measurement results of the residual enzyme activity in Experiment 6. [Figure 6] This is a graph showing the measurement results of the residual enzyme activity in Experiment 7. [Figure 7] This is a graph showing the measurement results of the residual enzyme activity in Experiment 8. [Figure 8] This is a graph comparing the concentrations of the main odor components detected in Samples No. 1 to 3 in Experiment 9. [Figure 9] This is a graph comparing the concentrations of the main odor components detected in Samples No. 4 to 7 in Experiment 9. [Figure 10] This is a graph comparing the concentrations of the main odor components detected in Samples No. 8 to 11 in Experiment 9. [Figure 11] This is a graph comparing the concentrations of the main odor components detected in Samples No. 1 and 8 in Experiment 9.

Modes for Carrying Out the Invention

[0027] <00001,26>A preferred embodiment of the present invention will be briefly described with reference to the drawings, illustrating the operation of the present invention.

[0028] In the present invention, when hot air heating is used in the sterilization process, the earthworms can also be dried by this hot air heating process, so the two processes of sterilization and drying can be performed simultaneously with this hot air heating process. Furthermore, when boiling is used in the sterilization process, the heating by this boiling process stimulates the earthworms and causes them to expel body fluid, so the two processes of sterilization and body fluid expulsion can be performed simultaneously with this boiling process.

[0029] Therefore, in the sterilization process, whether hot air heating or boiling is performed, either drying or body fluid drainage can be combined with it, reducing the processing time compared to conventional methods and enabling the efficient production of earthworm powder.

[0030] Furthermore, in the present invention, whether hot air heating or boiling is performed, the earthworms are heated, and this heating reduces the levels of 2-Phenylethanol and Ethyl laurate, which are thought to be the source of the earthworm's characteristic odor. This reduces the impact of the earthworm's characteristic odor on food, making it possible to apply earthworm powder directly to food. [Examples]

[0031] Specific embodiments of the present invention will be described with reference to the drawings.

[0032] This embodiment is a method for producing earthworm powder, comprising a filth removal treatment to remove residual filth from the earthworm's body, a body fluid discharge treatment to discharge body fluid from the earthworm, a sterilization treatment to kill the earthworm, a drying treatment to dry the earthworm, and a powdering treatment to turn the dried earthworm into powder, wherein the sterilization treatment is either a hot air heating treatment in which the earthworm from which the filth has been removed is heated with hot air at 150°C or higher, or a boiling treatment in which the earthworm is boiled in water.

[0033] The following describes in detail each process related to this embodiment.

[0034] <Removal and treatment of human waste> The fecal soil removal process involves removing the fecal soil from the earthworm's body and purifying its internal structure. In this embodiment, the fecal soil is removed (excreted) by fasting the earthworm in water.

[0035] Specifically, dechlorinated tap water (in this example, tap water that has been drawn and left to stand the day before) and an air pump are placed in a tank, earthworms that have been washed with tap water are placed in the tank, and the air pump is operated to supply air (oxygen) to the water while the earthworms are left unattended (fasting). (Without supplying air, the limit for fasting earthworms in water is 2-3 days, but by supplying air to the water, it becomes possible to fast them in water for a longer period, allowing them to sufficiently expel the fecal matter from their bodies.)

[0036] More specifically, the period of neglect (fasting period) should be 5 days, during which time the earthworms should be washed and the water in the tank changed daily (using dechlorinated tap water for the water change) to keep the tank clean and to prevent the earthworms from ingesting their own excrement.

[0037] Furthermore, the period of neglect is not limited to the above and may be adjusted as appropriate depending on the amount of fecal matter being discharged (specifically, until no more fecal matter is observed being discharged).

[0038] <Body cavity fluid drainage treatment> Body fluid drainage is a process that involves draining the body fluid, which is irritating and has a distinctive odor, stored inside the earthworm's body. This drainage is carried out using either a chemical method or a boiling method.

[0039] The chemical method involves immersing earthworms in an alkaline solution to stimulate them and induce the expulsion of body fluids. Suitable alkaline solutions include aqueous sodium hypochlorite solution and sodium bicarbonate solution.

[0040] When using an aqueous sodium hypochlorite solution as the alkaline solution, a solution with an effective chlorine concentration (NaClO concentration) of approximately 0.02% to 0.08% is preferable. When using a sodium bicarbonate solution, a sodium bicarbonate concentration of approximately 5 wt% is preferable.

[0041] Specifically, the amount of alkaline solution should be about 10 times the mass of the earthworms. The process involves alternating between immersion in the alkaline solution (immersion time is about 2 minutes for sodium hypochlorite solution and about 3 minutes for baking soda solution) and washing with pure water, repeating this 2-3 times until the discharge of body fluid is almost completely eliminated (until the color of the alkaline solution hardly changes from transparent even when the earthworms are immersed in it).

[0042] The boiling method involves placing earthworms and water in a container, heating the water in the container, and boiling (heating) the earthworms to stimulate them and cause them to expel body fluid.

[0043] Specifically, the water is heated from a cold state, brought to a boil, and then boiled for 1 to 10 minutes (continuing the heating) to expel the body fluid. In this boiling method, if earthworms are placed in boiling water, they will die immediately and the body fluid will not be expelled. Therefore, it is preferable to heat the water from a cold state to prevent the earthworms from dying immediately, and to apply a gradual, long-term stimulus to expel the body fluid.

[0044] <Sterilization treatment> Sterilization is a process that kills live bacteria present inside and outside the earthworms. This is done by either hot air heating, where earthworms with removed excrement are heated with hot air at 150°C or higher, or by boiling, where earthworms are boiled in water.

[0045] When sterilizing by hot air heat treatment, the use of an air fryer (also called a non-fryer) is preferable. In this example, an Innsky 1.8L air fryer (model number: IS-AF005) is used, and sterilization is performed by hot air heat treatment at a hot air temperature of 180℃±10℃ for a processing time of 15 minutes±5 minutes.

[0046] Furthermore, when sterilization is performed by boiling, the boiling process is carried out under the same conditions as the process described above for draining body fluids by boiling (boiling from water for 1 to 10 minutes).

[0047] In other words, in this embodiment, by using the boiling method in the body cavity fluid drainage process, sterilization is performed simultaneously with the boiling process for draining the body cavity fluid. This single boiling process can perform both body cavity fluid drainage and sterilization, thus eliminating the need for one additional step.

[0048] <Drying process> The drying process involves drying the earthworms, and in this embodiment, the earthworms are dried by freeze-drying or hot air heating.

[0049] When drying earthworms by freeze-drying, first, the earthworms are frozen in a deep freezer (around -80°C), and then these frozen earthworms are freeze-dried using a freeze-dryer (FDU-1200 manufactured by Tokyo Rikakikai (EYELA) Co., Ltd.) (processing time: approximately 70 hours).

[0050] Furthermore, when drying earthworms by hot air heating, the drying process should be carried out under the same conditions as the hot air heating treatment in the sterilization process described above.

[0051] In other words, in this embodiment, by setting the hot air heating conditions for the sterilization treatment and the hot air heating conditions for the drying treatment to the same conditions, the drying treatment of the earthworms is performed simultaneously with the hot air heating treatment for sterilization. Thus, both sterilization and drying treatments can be performed in this single hot air heating treatment, and one treatment step can be omitted.

[0052] <Powdering process> The powdering process involves turning dried earthworms into a powder, which is achieved by crushing them using a mixer.

[0053] Furthermore, in the pulverization process, the pulverization method (means) for earthworms is not limited to those described above, and any method that can turn earthworms into a powder may be used as appropriate.

[0054] As described above, in this embodiment, by performing a boiling treatment in the body cavity fluid drainage process (by using the foil method), the earthworms are sterilized simultaneously by this boiling treatment, and the subsequent sterilization treatment can be omitted.

[0055] Furthermore, by using hot air heating during the sterilization process, the earthworms are dried simultaneously, eliminating the need for a subsequent drying process.

[0056] In other words, in this embodiment, the sterilization process is performed by boiling or hot air heating. If the former, boiling, is selected, the earthworms are stimulated by boiling (heating), causing them to expel body fluids, and the subsequent boiling sterilizes the earthworms. Thus, this boiling process allows for the simultaneous performance of both body fluid expulsion and sterilization, resulting in the processing flow shown in Figure 1(a).

[0057] Furthermore, if the latter hot air heating treatment is selected, the earthworms can be dried by the hot air heating treatment, so both sterilization and drying treatments can be performed simultaneously with this hot air heating treatment, resulting in the treatment flow shown in Figure 1(b).

[0058] Therefore, this embodiment can reduce the number of steps required and efficiently produce earthworm powder compared to conventional methods.

[0059] Furthermore, in this embodiment, since the earthworms are heated in both the hot air heating treatment and the boiling treatment, this heating treatment can reduce 2-Phenylethanol and Ethyl laurate, which are odor components unique to earthworms. This reduces the characteristic earthworm odor when applied to food, making it possible to apply earthworm powder directly to food.

[0060] Furthermore, in this embodiment, when hot air heating is used, the hot air heating imparts a savory aroma to the powdered earthworms. This aroma reduces any unpleasant odors other than the characteristic earthworm smell, making it possible to apply the earthworm powder directly to food.

[0061] The following describes experimental examples (evaluations) that support the effectiveness of this embodiment.

[0062] In the experiments described below, Eisenia andrei was used as the earthworm, but other earthworm species such as Eisenia fetida, Lumbricus rubellus, Lumbricus terrestris, Drawida hattamimizu, Pheretima sp., Perionyx excavatus, and Eudrilus eugeniae may also be used.

[0063] <Experiment 1> In Experiment 1, the efficiency of removing body cavity fluids was confirmed when using a chemical method involving a sodium hypochlorite aqueous solution in the treatment of body cavity fluids.

[0064] Specifically, approximately 10g of earthworms, which had been kept in water without food for 5 days and had their fecal matter removed, were placed in containers (beakers) containing 10 times the amount of earthworm mass (density not considered) of sodium hypochlorite aqueous solution with effective chlorine concentrations (NaClO concentration): 0.02% (A1), 0.04% (A2), and 0.08% (A3). After allowing the earthworms to expel their coelom fluid, the earthworms were removed, and the absorbance and color of the liquid in the containers (sodium hypochlorite aqueous solution + coelom fluid) were measured.

[0065] In detail, as shown in Table 1, the immersion time in the sodium hypochlorite aqueous solution was set to 2 minutes, and this immersion-to-wash process for draining body fluids was repeated three times. After each process, the absorbance of the sodium hypochlorite aqueous solution from which the body fluids had been drained was measured using a spectrophotometer (V-630BIO, JASCO Corporation), and the color was observed visually. In the absorbance measurement, a significant peak was observed at 200 nm, so the absorbance at that point was multiplied by the dilution ratio used during measurement and converted to this value, which was defined as the "absorbance".

[0066] [Table 1]

[0067] As shown in Table 1, there was almost no difference in absorbance between the conditions (A1-A3) with varying effective chlorine concentrations (NaClO concentrations). Furthermore, as shown in Figure 2, visual observation of the color revealed that in all conditions, the sodium hypochlorite solution was darker (yellowish-white turbidity) after the first treatment, indicating the discharge of a large amount of body fluid. However, the color became lighter after the second treatment (almost no turbidity), and in the third treatment, the color remained almost unchanged (almost transparent, like the sodium hypochlorite solution) across all conditions (A1-A3) with varying effective chlorine concentrations (NaClO concentrations), indicating that very little body fluid was discharged.

[0068] From the above, it was confirmed that when using a sodium hypochlorite aqueous solution in the treatment of body cavity fluid drainage, setting the effective chlorine concentration (NaClO concentration) to 0.02% to 0.08% and repeating the treatment of immersing earthworms in this sodium hypochlorite aqueous solution with an effective chlorine concentration (NaClO concentration) of 0.02% to 0.08% for 2 minutes three times can drain almost all of the body cavity fluid from the earthworms.

[0069] <Experiment 2> In Experiment 2, the efficiency of removing body cavity fluids using a chemical method involving a sodium bicarbonate solution was confirmed.

[0070] Specifically, similar to Experiment 1, approximately 10g of earthworms, which had been kept in water without food for 5 days and had their fecal matter removed, were placed in a container (beaker) containing a 5wt% sodium bicarbonate solution in an amount 10 times the weight of the earthworms (density not considered). After the body fluid was drained, the earthworms were removed, and the absorbance and color of the liquid in the container (sodium bicarbonate solution + body fluid) were measured.

[0071] In detail, as shown in Table 2, the immersion time in the sodium bicarbonate solution was set to 1 to 3 minutes, and this process of draining body fluids from immersion to washing was repeated three times. After each treatment, the absorbance of the sodium bicarbonate solution from which the body fluids had been drained was measured using a spectrophotometer (V-630BIO, JASCO Corporation), and the color was observed visually. As in Experiment 1, a significant peak was observed at 200 nm in the absorbance measurement, so the absorbance at that point was multiplied by the dilution ratio used during measurement and converted to this value, which was defined as the "absorbance".

[0072] [Table 2]

[0073] As shown in Table 2, regarding absorbance, under condition B3, where the immersion time was set to 3 minutes (the longest time), the absorbance was highest after the first treatment and lowest after the third treatment. Furthermore, as shown in Figure 3, visual observation of the color revealed that in all conditions, the sodium bicarbonate solution was darker (yellowish-white turbidity) after the first treatment, indicating the discharge of a large amount of body cavity fluid. However, only under condition B3, where the immersion time was set to 3 minutes, did the color become almost transparent after the third treatment. In other words, only under condition B3, where the immersion time was set to 3 minutes, was it confirmed that the color hardly changed (almost transparent, like the sodium bicarbonate solution) after the third treatment, and that almost no body cavity fluid was discharged.

[0074] From the above, it was confirmed that when using a sodium bicarbonate solution in the treatment of draining body cavity fluid, setting the sodium bicarbonate concentration to 5 wt% and repeating the treatment of immersing earthworms in this 5 wt% sodium bicarbonate solution for 3 minutes three times can efficiently drain almost all of the body cavity fluid from the earthworms.

[0075] <Experiment 3> In Experiment 3, the efficiency of removing body cavity fluid when using the boiling method (boiling treatment) in the drainage of body cavity fluid was confirmed.

[0076] Specifically, similar to experiments 1 and 2, approximately 10g of earthworms, which had been kept in water without food for 5 days and had their fecal matter removed, were placed in a container (beaker) containing 10 times the amount of water (pure water) as the weight of the earthworms (density not considered). After the earthworms were boiled in this water to expel their coelomic fluid, or the water was boiled and the earthworms were boiled in this boiling water to expel their coelomic fluid, the earthworms were removed, and the absorbance and color of the liquid (water + coelomic fluid) in each container were measured.

[0077] In detail, as shown in Table 3, absorbance measurements were taken using a spectrophotometer (JASCO V-630BIO) and the color was observed visually for the coelom fluid discharged from water in two cases: when earthworms were placed in water, heated, boiled, and then boiled for 1 to 10 minutes; and when earthworms were placed in boiling water and boiled for 1 minute. As in experiments 1 and 2, a significant peak was observed at 200 nm in the absorbance measurement, so the absorbance at that point was multiplied by the dilution ratio used during measurement and converted to this value, which was defined as the "absorbance".

[0078] [Table 3]

[0079] As shown in Table 3, the absorbance values ​​were higher under the conditions where earthworms were placed in water, heated, boiled, and then the water was boiled (C1-C3) compared to Experiments 1 and 2, while the absorbance was lower under the condition where earthworms were placed in boiling water (C4). Furthermore, as shown in Figure 4, visual observation of the color revealed that under the conditions where earthworms were placed in water, heated, boiled, and then the water was boiled (C1-C3), the color was a darker yellow compared to the observation results after the first treatment in Experiments 1 and 2, confirming that a large amount of coelom fluid was discharged. However, under the condition where earthworms were placed in boiling water (C4), the color hardly changed (almost transparent, like boiling water), confirming that almost no coelom fluid was discharged. This is thought to be because the earthworms died immediately when placed in boiling water and did not discharge coelom fluid.

[0080] Furthermore, since the earthworms die from boiling even when heated from water, unlike in experiments 1 and 2, it was not possible to repeatedly perform the coelom fluid drainage process, and absorbance measurements could only be taken once.

[0081] From the above, it was confirmed that when using boiling treatment (boiling method) in the treatment of body cavity fluid, boiling the earthworms by heating water first allows for the efficient drainage of a large amount of body cavity fluid.

[0082] Furthermore, when using the boiling method, it was found that boiling kills the earthworms, so it is better to boil (heat) them slowly over a long period of time to efficiently expel the body fluid.

[0083] <Experiment 4> In Experiment 4, the sterilization effect of using hot air heating treatment in the sterilization process was confirmed.

[0084] Since there are currently no established food hygiene standards for earthworm powder, we independently set food hygiene standards (sterilization target values) for earthworm powder as shown in Table 4, referencing the standards for general bacteria and coliform bacteria for heated prepared foods as defined in the Niigata Prefecture Food Guidance Standards (http: / / www.fureaikan.net / syokuinfo / 02terakoya / tera03 / tera03_02_07.html), and the standards for mold and yeast as defined in the Ministry of Health, Labour and Welfare's Pickled Food Hygiene Standards (https: / / www.mhlw.go.jp / stf / shingi / 2r9852000002kxlb-att / 2r9852000002kxr7.pdf), and confirmed whether or not these standards were met.

[0085] [Table 4]

[0086] Specifically, earthworms that had undergone coelomic fluid drainage treatment under each of the treatment conditions in Experiments 1-3 (A1-A3, B1-B3, C1-C4) were placed in sterilized containers and subjected to hot air heating treatment at 180°C for 15 minutes in a preheated air fryer (Innsky 1.8L air fryer IS-AF005) to sterilize and simultaneously dry the earthworms. These sterilized and dried earthworms were then ground into a powder using a mixer, and a viability test was performed on this powdered earthworm (powdered earthworm).

[0087] In addition to the earthworms that underwent the above-mentioned coelomal fluid drainage treatment (A1-A3, B1-B3, C1-C4), the viability test was also performed on two comparative test subjects: raw earthworms processed into a paste (Control) and untreated earthworms that were sterilized by hot air heating (180°C, 15 minutes) and dried into a powder without the removal of fecal matter or the drainage of coelomal fluid (Untreated).

[0088] Specifically, 0.5g of earthworm powder contains calcium 2+ Mg 2+The bacterial solution was suspended in 5 mL of phosphate-buffered saline (hereinafter referred to as "PBS(-)") that does not contain phosphate-buffered bacteria, and the residue and filtrate were separated using a sterile bag with a filter (AS ONE Sanispec Test Bag Mini (with filter)) to obtain a 10-fold diluted bacterial solution (stock solution). This 10-fold diluted bacterial solution was then diluted 100-fold and 1,000-fold with PBS(-). 1,000 μL of the bacterial solution was dropped onto AC plates for general viable bacteria, RCC plates for coliform bacteria, and YM plates for yeast and mold, and spread with a spreader (all plates were manufactured by 3M). Subsequently, the AC plates were cultured at 35°C for 48 hours, the RCC plates at 35°C for 24 hours, and the YM plates at 25°C for 5 days. After culturing, the number of viable bacteria (colony count) was measured.

[0089] Table 5 shows the results of the viable bacteria test in Experiment 4. As shown in Table 5, no viable bacteria were detected in any of the samples that were sterilized by hot air heating treatment using an air fryer. This confirms that viable bacteria can be killed by hot air heating treatment. Note that "no viable bacteria detected" means that no colonies were observed on a 10-fold dilution plate for general viable bacteria, and no colonies were observed on a 100-fold dilution plate for coliform bacteria, molds, and yeasts.

[0090] [Table 5]

[0091] <Experiment 5> In Experiment 5, the sterilization effect of using boiling treatment in the sterilization process was confirmed (the reference value was the same as in Experiment 4).

[0092] Specifically, the earthworms that underwent the treatment conditions of Experiment 3 (C1-C4), namely, the boiling method to drain body fluid and sterilize them, were placed in boiled containers and dried in a freeze-dryer (FDU-1200, manufactured by Tokyo Science Instruments Co., Ltd. (EYELA)) at -80°C for 70 hours. These boiled and freeze-dried earthworms were then powdered using a mixer, and a viability test was performed on this powdered earthworm (powdered earthworm).

[0093] In addition to the earthworms that underwent the above-mentioned coelomic fluid drainage treatment (C1-C4), the viability test was also performed on comparative test subjects: raw earthworms processed into a paste (Control) and untreated earthworms that had not undergone the fecal soil removal treatment or coelomic fluid drainage treatment but had been freeze-dried (-80°C, 70 hours) to produce a powder.

[0094] Specifically, 0.7g of earthworm powder was suspended in 7mL of PBS(-), and the residue and filtrate were separated using a sterile bag with a filter (AS ONE Sanispec Test Bag Mini (with filter)) to obtain a 10-fold diluted bacterial solution (stock solution). This 10-fold diluted bacterial solution was then diluted 100-fold and 1,000-fold with PBS(-). 1,000μL of the bacterial solution was dropped onto AC plates for general viable bacteria, RCC plates for coliform bacteria, and YM plates for yeast and mold, and spread using a spreader (all plates were manufactured by 3M). Subsequently, the AC plates were cultured at 35°C for 48 hours, the RCC plates at 35°C for 24 hours, and the YM plates at 25°C for 5 days. After culturing, the number of viable bacteria (colony count) was measured.

[0095] Table 6 shows the results of the viable bacteria test in Experiment 5. As shown in Table 6, no viable bacteria were detected in the samples sterilized by boiling, regardless of the boiling time or any other treatment condition. This confirms that viable bacteria can be killed by boiling.

[0096] [Table 6]

[0097] <Experiment 6> In Experiment 6, the residual enzyme activity of earthworm powder was confirmed using a sodium hypochlorite aqueous solution in the treatment of body cavity fluid drainage.

[0098] Specifically, we measured the activity of five representative earthworm digestive enzymes that are thought to affect the use of earthworm powder as food. These enzymes were: lumbrokinase activity, α-amylase activity, endoglucanase (EG) activity, β-glucosidase (BGL) activity, and lipase activity. This was done for powdered earthworms (A1-A3) treated with sodium hypochlorite aqueous solution for body fluid drainage in Experiment 4, raw earthworms processed directly into a paste (Control), and untreated earthworms that were sterilized and dried by hot air heating (180°C, 15 minutes) without removing fecal matter or body fluid drainage.

[0099] In detail, lumbrokinase activity was calculated by measuring the absorbance of S-2251 (plasmin substrate, manufactured by Sekisui Medical Co., Ltd.) and S-2288 (t-PA substrate, manufactured by Sekisui Medical Co., Ltd.) using a microplate reader (Corona Grating Microplate Reader SH-9000, manufactured by Corona Electric Co., Ltd.) at a wavelength of 405 nm and 37°C.

[0100] Furthermore, α-amylase activity was calculated using an α-amylase measurement kit (manufactured by Kikkoman Biochemifa Co., Ltd.).

[0101] Furthermore, endoglucanase (EG) activity was calculated using the DNS method.

[0102] Furthermore, β-glucosidase (BGL) activity was calculated by measuring the absorbance of p-NPG as a substrate using a microplate reader (Corona Grating Microplate Reader SH-9000, manufactured by Corona Electric Co., Ltd.) at a wavelength of 405 nm and 40°C.

[0103] Furthermore, lipase activity was calculated using a lipase activity measurement reagent (Lipase kit S, manufactured by Sumitomo Bakelite Co., Ltd.).

[0104] Figure 5 shows the results of measuring residual enzyme activity in Experiment 6. As shown in Figure 5, in the cases where sodium hypochlorite aqueous solution was used for body cavity fluid drainage (A1-A3), inactivation of most enzymes was confirmed, but endoglucanase remained, and furthermore, its activity value (specific activity) was confirmed to be higher than that of the Control and Untreated groups.

[0105] From the above, it was confirmed that when sodium hypochlorite aqueous solution was used for the treatment of body cavity fluid drainage, the activity of cellulase-type enzymes (endoglucanase) increased, but other enzymes were inactivated. Furthermore, since the endoglucanase that was not inactivated had almost no effect on the shaping of the food, it was confirmed that earthworm powder treated with sodium hypochlorite aqueous solution for body cavity fluid drainage can be applied to food.

[0106] <Experiment 7> In Experiment 7, the residual enzyme activity of earthworm powder was confirmed using a sodium bicarbonate solution during the treatment of body cavity fluid drainage.

[0107] Specifically, the same procedures as in Experiment 6 were followed for powdered earthworms (B1-B3) treated with a sodium bicarbonate solution for body fluid drainage (as used in Experiment 4), raw earthworms processed directly into a paste (Control), and untreated earthworms that were sterilized and dried by hot air heating (180°C, 15 minutes) and then powdered without the removal of fecal matter or body fluid drainage (Untreated).

[0108] Figure 6 shows the results of measuring residual enzyme activity in Experiment 7. As shown in Figure 6, in the cases where sodium bicarbonate solution was used for body cavity fluid drainage (B1-B3), inactivation of most enzymes was confirmed, similar to the case where sodium hypochlorite aqueous solution was used, except for endoglucanase, which remained. However, it was confirmed that the activity value (specific activity) was considerably lower than in the case of sodium hypochlorite aqueous solution (approximately 1 / 4).

[0109] From the above, it was confirmed that when a sodium bicarbonate solution is used for the treatment of body cavity fluid drainage, the activity of cellulase-type enzymes (endoglucanase) increases, but other enzymes are inactivated. Furthermore, even for endoglucanase that does not lose activity, the activity level is considerably low, and as mentioned above, endoglucanase has almost no effect on the shaping of food. Therefore, it was confirmed that earthworm powder treated with a sodium bicarbonate solution for body cavity fluid drainage can also be applied to food.

[0110] <Experiment 8> In Experiment 8, the residual enzyme activity of earthworm powder was confirmed using the boiling method (boiling treatment) in the treatment of body cavity fluid drainage.

[0111] Specifically, the same procedures as in Experiment 6 were followed for powdered earthworms (C1-C4) treated with the boiling method used in Experiment 4 to remove coelom fluid, raw earthworms processed directly into a paste (Control), and untreated earthworms that were sterilized and dried by hot air heating (180°C, 15 minutes) without removing fecal matter or removing coelom fluid, and then powdered (Untreated).

[0112] Figure 7 shows the results of measuring residual enzyme activity in Experiment 8. As shown in Figure 7, in the cases where the boiling method (boiling treatment) was used for the body cavity fluid drainage treatment (C1-C4), inactivation of most enzymes was confirmed, similar to the cases where sodium hypochlorite solution or baking soda was used. However, β-glucosidase and endoglucanase remained, and furthermore, for endoglucanase, the activity value (specific activity) was confirmed to be higher than that of the Control and Untreated cases, similar to the sodium hypochlorite solution.

[0113] From the above, it was confirmed that when the boiling method (boiling treatment) is used for the treatment of body cavity fluid drainage, the enzyme activity of cellulase-type enzymes (β-glucosidase, endoglucanase) remains, but other enzymes are inactivated. Furthermore, the specific activity (activity value) of β-glucosidase, which does not lose activity, is quite low, and as mentioned above, endoglucanase has almost no effect on the shaping of food. Therefore, it was confirmed that earthworm powder treated with the boiling method (boiling treatment) for body cavity fluid drainage can also be applied to food products.

[0114] <Experiment 9> In Experiment 9, the odor components of the earthworm powder in this example were identified.

[0115] Specifically, odor components were measured for each earthworm powder sample (samples No. 1-11) shown in Table 7 using gas chromatography-mass spectrometry (GC-MS) under the conditions shown in Table 8. The data was analyzed using an MRM database.

[0116] [Table 7]

[0117] [Table 8]

[0118] Figure 8 is a graph comparing the concentrations of major odor components detected in samples No. 1-3 (body fluid drainage treatment: none or chemical method + drying treatment: hot air heating).

[0119] As shown in Figure 8, in the sample (Sample No. 1) which did not undergo body fluid drainage treatment and was dried using hot air heating treatment, substances such as 1-Octen-3-one, Caproic acid, 1-Octen-3-ol, Pantolactone, and n-Decanal were detected as the main components.

[0120] Furthermore, a comparison of the concentrations of odor components in each sample revealed that the condition using a sodium bicarbonate solution for the treatment of body cavity fluid in sample No. 3 resulted in lower concentrations of all components except 1-octen-3-one, confirming its suitability for food.

[0121] Figure 9 is a graph comparing the concentrations of major odor components detected in samples No. 4-7 (body fluid drainage treatment: boiling method + drying treatment: hot air heating).

[0122] As shown in Figure 9, when the boiling method (boiling treatment) was used for the body cavity fluid drainage treatment and the hot air heating treatment was used for the drying treatment, almost the same components as when the chemical method was used were detected. However, it was confirmed that the concentrations of 1-Octen-3-one, 1-Octen-3-ol, and Pantolactone were higher than when the chemical method was used. Furthermore, there was almost no difference due to differences in treatment conditions (differences in treatment time).

[0123] Figure 10 is a graph comparing the concentrations of major odor components detected in samples No. 8-11 (body fluid drainage treatment: none, chemical method, or boiling method + drying treatment: freeze-drying).

[0124] As shown in Figure 10, when samples treated with body fluid drainage under various conditions were dried by freeze-drying, a decrease in the concentration of odor components was observed overall. In particular, when body fluid drainage was performed with a sodium bicarbonate solution, a decrease in concentration was observed for almost all components, with a few exceptions, and it was clear that this method was superior in reducing odor compared to treatment with a sodium hypochlorite aqueous solution.

[0125] Figure 11 is a graph comparing the concentrations of major odor components detected in sample No. 1 (no body fluid drainage treatment + hot air heating) and sample No. 8 (no body fluid drainage treatment + freeze-drying) (a graph comparing the concentrations of odor components due to differences in drying treatment).

[0126] Similar to the comparison results of odor component concentrations under freeze-drying conditions for samples treated with the aforementioned body fluid drainage process under various conditions (none, chemical method, or boiling method), 2-Phenylethanol and Ethyl laurate were not detected under hot-air drying conditions, but were detected only under freeze-drying conditions. Therefore, it was considered that these are components that cause the characteristic earthworm odor in earthworm powder. Accordingly, it was confirmed that the present invention, which involves heat treatment, reduces 2-Phenylethanol and makes it possible to produce earthworm powder suitable for food with a reduced characteristic earthworm odor.

[0127] Furthermore, pyrazines such as 2-Ethyl-3,6-dimethylpyrazine were detected during drying by hot air heating.

[0128] These pyrazines are components that are specifically detected when hot air heating is used in the drying process, and their characteristic odor is a "roasted smell, nutty smell" (a so-called savory aroma).

[0129] The earthworm powder that underwent hot air heating treatment during the manufacturing process had a savory aroma. This indicates that the pyrazines and other compounds imparted the savory aroma, and that the influence of other components in the earthworm powder (earthworm-specific odors other than 2-Phenylethanol), as shown in Figures 8 and 9, was reduced.

[0130] Based on the results of experiments 1 to 9, it was found that in the processing flow shown in Figure 1(a), it is preferable to perform the body cavity fluid drainage and sterilization treatment by boiling water for 5 minutes, and to perform the drying treatment by freeze-drying. Furthermore, in the processing flow shown in Figure 1(b), it was found that it is preferable to perform the body cavity fluid drainage treatment by repeatedly immersing the sample in a 5 wt% sodium bicarbonate solution for 3 minutes three times, and to perform the sterilization and drying treatment by hot air heating.

[0131] It should be noted that the present invention is not limited to this embodiment, and the specific configuration of each constituent element can be designed as appropriate.

Claims

1. A method for producing earthworm powder, comprising: a filth removal treatment to remove any remaining filth from the body of the earthworm to be powdered; a body fluid discharge treatment to discharge body fluid from the earthworm; a sterilization treatment to kill the earthworm; a drying treatment to dry the earthworm; and a powdering treatment to turn the dried earthworm into powder, wherein the sterilization treatment is either a hot air heating treatment in which the earthworm from which the filth has been removed is heated with hot air at 150°C or higher, or a boiling treatment in which the earthworm from which the filth has been removed is boiled in water.

2. A method for producing earthworm powder according to claim 1, characterized in that the sterilization treatment and the drying treatment are performed simultaneously by the hot air heating treatment.

3. A method for producing earthworm powder according to claim 2, characterized in that the hot air heating treatment is performed with a hot air temperature of 180°C ± 10°C and a treatment time of 15 minutes ± 5 minutes.

4. A method for producing earthworm powder according to claim 2, characterized in that the body cavity fluid drainage treatment is a treatment in which the earthworms are immersed in an alkaline solution.

5. A method for producing earthworm powder according to claim 3, characterized in that the body cavity fluid drainage treatment is a treatment in which the earthworms are immersed in an alkaline solution.

6. A method for producing earthworm powder according to claim 4, characterized in that the body cavity fluid drainage treatment is a process in which the earthworms are repeatedly and alternately subjected to an immersion treatment in which they are submerged in the alkaline solution and a pure water washing treatment in which they are washed with pure water.

7. A method for producing earthworm powder according to claim 5, characterized in that the body cavity fluid drainage treatment is a process in which the earthworms are alternately subjected to an immersion treatment in which they are submerged in the alkaline solution and a pure water washing treatment in which they are washed with pure water, repeated multiple times.

8. A method for producing earthworm powder according to claim 1, characterized in that the body cavity fluid removal treatment and the sterilization treatment are performed simultaneously by the boiling treatment.

9. A method for producing earthworm powder according to claim 8, characterized in that the boiling treatment is a process of placing earthworms and water in a container, heating the water, and boiling for 1 minute or more.

10. A method for producing earthworm powder according to claim 8, characterized in that the drying treatment is freeze-drying or hot air heating.

11. A method for producing earthworm powder according to claim 9, characterized in that the drying treatment is freeze-drying or hot air heating.

12. A method for producing earthworm powder according to any one of claims 1 to 11, characterized in that the excrement removal treatment is a treatment in which earthworms are fasted and reared in water while air is supplied.

13. A method for producing earthworm powder according to claim 12, characterized in that the water is dechlorinated tap water.

14. A method for producing earthworm powder according to any one of claims 1 to 11, characterized in that the earthworm is one of Eisenia andrei, Eisenia fetida, Lumbricus rubellus, Lumbricus terrestris, Drawida hattamimizu, Pheretima sp., Perionyx excavatus, and Eudrilus eugeniae.

15. A method for producing earthworm powder according to claim 12, characterized in that the earthworm is any of Eisenia andrei, Eisenia fetida, Lumbricus rubellus, Lumbricus terrestris, Drawida hattamimizu, Pheretima sp., Perionyx excavatus, and Eudrilus eugeniae.

16. A method for producing earthworm powder according to claim 13, characterized in that the earthworm is any of Eisenia andrei, Eisenia fetida, Lumbricus rubellus, Lumbricus terrestris, Drawida hattamimizu, Pheretima sp., Perionyx excavatus, and Eudrilus eugeniae.

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