Methods for producing fermented foods

Abstract

To provide a production method of a fermented food obtained by using the bone of a vertebrate as a main raw material.SOLUTION: A production method of a fermented food in which the fermented food is obtained by using the bone of a vertebrate as a main raw material includes: a protein extraction step of extracting protein from the main raw material by adding an organic acid and water to the main raw material and heating the resultant; a protein degradation step of adding at least one of a proteolytic enzyme or koji to the protein extracted in the protein extraction step to degrade the protein; and a fermentation step of adding at least one of a lactic acid bacterium or yeast to an extracted degraded product composed of the protein degraded in the protein degradation step to ferment the extracted degraded product.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a fermented food, and particularly to a method for producing a fermented food using vertebrate bones as a main raw material. [Background Art]

[0002] It is known that the umami taste of "dashi" is enhanced by the synergistic effect of nucleic acids (e.g., inosinic acid and guanylic acid) and amino acids (e.g., glutamic acid) (see, for example, Non-Patent Document 1). Accordingly, the inventors of the present application have proposed a method for producing a fermented food, which uses krill as a raw material and comprises: an enzymatic decomposition step of adding koji, water and salt to perform enzymatic decomposition; and a fermentation step of inoculating salt-tolerant yeast and salt-tolerant lactic acid bacteria for fermentation (see, for example, Patent Document 1). [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2015-181414 [Non-Patent Literature]

[0004] [Non-Patent Document 1] Specific Non-Profit Organization Umami Information Center, "The Global Appeal of Umami: Discovery of Nucleic Acid-Based Umami Substances and Synergistic Effects", [online], [searched on April 2, Reiwa 5], Internet <URL:https: / / www.umamiinfo.jp / what / attraction / discovery / > [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] Incidentally, the bones of vertebrates (for example, fish, livestock, or birds) were mostly discarded, except for being used in some specialty shops where they were boiled for a long time to extract umami and then used to make broth. Furthermore, there are no known fermented foods that use protein extracted from these bones and then produce amino acids using proteolytic enzymes to enhance the umami flavor.

[0006] In view of the circumstances described above, at least one embodiment of the present invention aims to provide a method for producing fermented food using vertebrate bones as the main ingredient. [Means for solving the problem]

[0007] (1) A method for producing fermented food according to at least one embodiment of the present invention is: A method for producing fermented foods using vertebrate bones as the main ingredient, A protein extraction step is performed by adding an organic acid and water to the main raw material and heating it to extract protein from the main raw material. A protein degradation step is performed by adding at least one of a proteolytic enzyme or koji to the protein extracted in the protein extraction step to degrade the protein, In the protein degradation step, at least one of lactic acid bacteria or yeast is added to the extract hydrolysate obtained by the protein degradation step, and a fermentation step is performed to ferment the extract hydrolysate. It has.

[0008] According to the manufacturing method described in (1) above, by adding an organic acid and water to the main raw material and heating it, protein, mainly collagen, can be extracted from the bones of vertebrates, which are the main raw material. Subsequently, by adding at least one of a proteolytic enzyme or koji to the protein extracted in the protein extraction step, the protein extracted in the protein extraction step is broken down, and by adding at least one of lactic acid bacteria or yeast to the hydrolyzed extract obtained in the protein decomposition step, the hydrolyzed extract obtained in the protein decomposition step can be fermented. This provides a method for producing fermented food using vertebrate bones as the main raw material.

[0009] (2) In some embodiments, in the manufacturing method of (1) above, The heating in the protein extraction step is continued at a temperature of 100 degrees Celsius or higher for 10 minutes or more.

[0010] According to the manufacturing method described in (2) above, by continuously heating the main raw material, to which organic acid and water have been added, at a temperature of 100 degrees Celsius or higher for 10 minutes or more, protein can be efficiently extracted from the bones of vertebrates, which are the main raw material.

[0011] (3) In some embodiments, in the manufacturing method of (1) above, The concentration of the organic acid is 0.01 weight-force or more and 0.10 weight-force or less, when the main raw material is set to 100 weight-force.

[0012] According to the manufacturing method described in (3) above, by setting the concentration of the organic acid to 0.01 weights or more and 0.10 weights when the main raw material is set to 100 weights, proteins can be efficiently extracted from the bones of vertebrates, which are the main raw material.

[0013] (4) In some embodiments, in the manufacturing method of (1) or (3) above, The aforementioned organic acid is acetic acid.

[0014] According to the manufacturing method described in (4) above, by using acetic acid as the organic acid, the extraction rate of amino acids and proteins is higher than that of other organic acids (for example, citric acid, succinic acid, or lactic acid), enabling efficient extraction of amino acids and proteins. [Effects of the Invention]

[0015] According to at least one embodiment of the present invention, a method for producing fermented food using vertebrate bones as the main ingredient can be provided. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic process diagram showing the method for producing a fermented food according to the embodiment. [Figure 2] It is a diagram showing the relationship between the type and concentration of organic acids and the extraction rate of amino acids and proteins. [Figure 3] It is a diagram showing the extraction rate of amino acids and proteins, which shows the extraction rate when both the protein extraction step and the protein decomposition step are performed, and the extraction rate when only the protein decomposition step is performed. [Figure 4] It is a diagram showing the relationship between the number of days elapsed after adding at least one of lactic acid bacteria or yeast to the extract decomposed product in the fermentation step and formol nitrogen. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, and are merely illustrative examples. For example, expressions representing relative or absolute arrangements such as "in a direction", "along a direction", "parallel", "perpendicular", "center", "concentric", or "coaxial" not only strictly represent such arrangement, but also represent a state of relative displacement with tolerances or angles and distances that allow the same function to be obtained. In addition, for example, expressions representing shapes such as a square shape or a cylindrical shape not only represent shapes such as a square shape or a cylindrical shape in a strictly geometric sense, but also represent shapes including uneven portions, chamfered portions, and the like within a range where the same effect can be obtained. On the other hand, the expressions "comprising", "comprises", "provided with", "including", or "having" one element are not exclusive expressions that exclude the presence of other elements.

[0018] [Main raw material of fermented food] The method for producing a fermented food according to the embodiment is a method for producing a fermented food using vertebrate bones as a main raw material. At least one vertebrate used as the main raw material is selected from edible vertebrates such as fish, livestock and birds, but a plurality of vertebrates may be used. The fish are, for example, fish included in Perciformes, Anguilliformes or Tetraodontiformes, but are not limited thereto. Perciformes include, for example, sea bream, jack mackerel, yellowtail and sea bass; Anguilliformes include, for example, conger eel, pike eel and eel. Tetraodontiformes include, for example, tiger puffer and porcupinefish, but are limited to edible species. In addition, although not included in the above groups, bones of freshwater fish such as sharks, carp, char and crucian carp may be used as the main raw material. Livestock are, for example, even-toed ungulate mammals, but are not limited thereto. Artiodactyla includes pigs, cattle and sheep. Birds are, for example, birds included in Anseriformes or Galliformes, but are not limited thereto. Anseriformes includes ducks, and Galliformes includes chickens. In addition, although not included in the above groups, bones of amphibians such as soft-shelled turtles and edible frogs may be used as the main raw material. Vertebrate bones may be those from which meat or flesh has simply been removed, dried bones, flavored bones, or powdered bones.

[0019] [Auxiliary raw materials of fermented food] In the method for producing a fermented food according to the embodiment, when fish bones are used as the main raw material, fish skin and scales may be used as auxiliary raw materials, but this is not essential. When fish skin and scales are used as auxiliary raw materials, it is mandatory to subject them to a sterilization process at 60°C to 121°C, preferably 100°C, for an appropriate period of time.

[0020] [Outline of method for producing fermented food] FIG. 1 is a process diagram schematically showing the method for producing a fermented food according to the embodiment. As shown in FIG. 1, the method for producing a fermented food according to the embodiment comprises a protein extraction step (step S1), a protein decomposition step (step S2), and a fermentation step (step S3).

[0021] [Protein extraction step] The protein extraction process (step S1) is a process of extracting protein from the main raw material 11 by adding organic acid 12 and water 13 to the main raw material 11 and heating it. For example, in Figure 1, fish bones are shown as the main raw material 11, but as mentioned above, the main raw material 11 is not limited to fish bones.

[0022] Figure 2 shows the relationship between the type and concentration of organic acid 12 and the extraction rate of amino acids and proteins. Figure 2 shows, as control experiments, extraction by adding a strong acid (hydrochloric acid) to the main raw material 11 (strong acid extraction) and extraction by adding water 13 to the main raw material 11 (water extraction). As shown in Figure 2, the organic acid 12 added to the main raw material 11 can be, for example, acetic acid, citric acid, succinic acid, or lactic acid. However, citric acid yields a lower extraction rate of amino acids and proteins than the water extraction used in the control experiment, so acetic acid, succinic acid, or lactic acid are preferable to citric acid. The concentration of the organic acid 12 is determined, for example, in the range of 0.01 to 1.0 weight (weight percent) relative to 100 weight of the main raw material 11 (vertebrate bone). However, for any organic acid 12, there is no significant difference in the extraction rate of amino acids and proteins between 0.04 weight percent and 1.0 weight percent. Considering the effect on taste, it is preferable to determine the concentration in the range of 0.01 to 0.04 weight percent. Referring to Figure 2, it is preferable to determine the amount of acetic acid in the range of 0.02 to 0.04 weight percent.

[0023] Water 13 may be, for example, drinking water, but may also be saline solution. The saline solution may be, for example, 10 to 20 weight percent saline solution, preferably 19 weight percent saline solution.

[0024] Heating may be carried out, for example, by continuing at a temperature of 100 degrees Celsius or higher for 10 minutes or more. Alternatively, the water 13 added to the main ingredient 11 may be heated for 30 minutes to 3 hours after it has come to a boil, or it may be heated under pressure in a pressure cooker or the like for about 10 minutes.

[0025] [Protein degradation process] The protein degradation step (step S2) is a step in which at least one of a protease 14 or koji 15 is added to the protein extracted from the main raw material 11 in the protein extraction step (step S1) to degrade the protein. The protease 14 is, for example, a protease extracted from koji mold, and commercially available proteases, such as Kokurase (registered trademark) sold by Mitsubishi Chemical Corporation, are used, but are not limited to this. The koji 15 is, for example, rice koji, barley koji, soybean koji, or soy sauce koji, but is not limited to these.

[0026] Figure 3 shows the extraction rates of amino acids and proteins, comparing the extraction rate when both the protein extraction process (Step S1) and the protein degradation process (Step S2) are followed (bone extraction process + enzymatic degradation), and the extraction rate when only the protein degradation process (Step S2) is followed (enzymatic degradation only). As shown in Figure 3, the extraction rate of amino acids and proteins when both the protein extraction process (Step S1) and the protein degradation process (Step S2) are followed is 96 weight percent, while the extraction rate of amino acids and proteins when only the protein degradation process (Step S2) is followed is 26 weight percent. From this, it is clear that in order to extract umami amino acids for fermented foods, both the protein extraction process (Step S1) and the protein degradation process (Step S2) are required.

[0027] [Fermentation process] The fermentation step (step S3) is a step in which at least one of lactic acid bacteria 16 or yeast 17 is added to the extract hydrolysate obtained in the protein degradation step (step S2), and the extract hydrolysate is fermented. Either lactic acid bacteria 16 or yeast 17 may be added to the extract hydrolysate, or a mixture of lactic acid bacteria 16 and yeast 17 may be added. Lactic acid bacteria 16 are selected from edible lactic acid bacteria such as Lactobacillus species including Lactobacillus plantarum and Lactobacillus brevis, and Pediococcus species (Tetragenococcus species). Yeast 17 are selected from genus Saccharomyces such as sake yeast, wine yeast, shochu yeast, beer yeast, and yeast for soy sauce and miso (Zygosaccharomyces species).

[0028] Furthermore, lactic acid bacteria 16 or yeast 17 are cultured for 3 days at 30 degrees Celsius in a glucose-yeast extract-peptone medium, for example. Then, after the protein degradation process (step S2) has been performed, the extracted hydrolysate is cooled to 30 degrees Celsius, and then lactic acid bacteria 16 or yeast 17 are added to the extracted hydrolysate so that they make up about 1 percent of the total volume, and the extracted hydrolysate is fermented at a temperature between 10 and 40 degrees Celsius.

[0029] Figure 4 shows the relationship between the number of days elapsed since adding at least one of lactic acid bacteria 16 or yeast 17 to the extracted hydrolysate in the fermentation process (step S3) and the amount of formol nitrogen (mass percentage). Soluble amino acids dissolved in the solution can be estimated by measuring the amount of formol nitrogen. As shown in Figure 4, the amount of formol nitrogen increases from the time at least one of lactic acid bacteria 16 or yeast 17 was added to the extracted hydrolysate until day 10. This suggests that the protein extracted from the backbone of the pufferfish was converted into lower molecular weight peptides and amino acids from the time at least one of lactic acid bacteria 16 or yeast 17 was added to the extracted hydrolysate until day 10.

[0030] [Other processes] As shown in Figure 2, the fermented food produced by the fermented food production method according to the above embodiment is further processed through a pressing step (step S4), a sterilization and heat treatment step (step S5), and a filtration and sedimentation step (step S6) to become a product that is then offered to the market.

[0031] [Pressing process] The pressing step (step S4) is a process in which the liquid portion is collected from the mash by pressing the extracted decomposition product (mash) that has been fermented in the fermentation step (step S3), and the mash is separated into pressed lees 18 and pressed liquid 19. The pressing step (step S4) is an optional step, and the mash after fermentation may be offered to the market as a fermented food product.

[0032] [Sterilization and heating process] The sterilization and heat treatment process (Step S5) is a process of heating and sterilizing the fermented food. In the sterilization and heat treatment process (Step S5), it is preferable to heat and sterilize at 70 to 85 degrees Celsius to prevent discoloration. The sterilization and heat treatment process (Step S5) is an optional step, and if contamination by unwanted bacteria can be prevented in the preceding processes, including the protein extraction process (Step S1), the protein decomposition process (Step S2), and the fermentation process (Step S3), the product may be offered to the market without heat treatment.

[0033] [Filtration and draining process] The filtration and sedimentation step (step S6) is a process of removing sediment from the pressed liquid 19 separated in the pressing step (step S4) by allowing it to settle. By filtering the pressed liquid 19 from which the sediment has been removed, a clear fermented food (fermented seasoning) can be obtained. Note that the filtration and sedimentation step (step S6) is an optional step, and the pressed liquid 19 separated in the pressing step (step S4) may be offered to the market as a product.

[0034] [Product form] Fermented foods produced by the above-described method of manufacturing fermented foods may be marketed as fermented foods (products) using the mash after fermentation. Alternatively, the pressed liquid 19 may be marketed as a fermented seasoning (product) without heating. Furthermore, the pressed lees 18 may be marketed as fermented foods (products). Additionally, the pressed liquid 19 may be marketed as a fermented seasoning (product) with the sediment still attached.

[0035] [effect] According to the method for producing fermented food according to the embodiment described above, by adding organic acid 12 and water 13 to the main ingredient 11 and heating, protein, mainly collagen, can be extracted from the bones of vertebrates, which are the main ingredient 11. Subsequently, by adding at least one of proteolytic enzyme 14 or koji 15 to the protein extracted in the protein extraction step (step S1), the protein extracted in the protein extraction step (step S1) is decomposed, and by adding at least one of lactic acid bacteria 16 or yeast 17 to the hydrolyzed extract in the protein decomposition step (step S2), the hydrolyzed extract can be fermented. This provides a method for producing fermented food using bones of vertebrates as the main ingredient 11.

[0036] Furthermore, by continuously heating the main raw material 11, to which organic acid 12 and water 13 have been added, at a temperature of 100 degrees Celsius or higher for 10 minutes or more, proteins can be efficiently extracted from the bones of vertebrates, which are the main raw material 11.

[0037] Furthermore, by setting the concentration of the organic acid 12 to 0.01 weight-force or more, and 0.10 weight-force, when the main raw material 11 is set to 100 weight-force, proteins can be efficiently extracted from the bones of vertebrates, which are the main raw material 11.

[0038] Furthermore, by using acetic acid as organic acid 12, the extraction rate of amino acids and proteins is higher than with other organic acids 12 (for example, citric acid, succinic acid, or lactic acid), enabling efficient extraction of amino acids and proteins. [Examples]

[0039] [Main ingredients of fermented foods] As described above, the main raw material of the fermented food according to the embodiment is the bone of a vertebrate, and the amount of protein was measured using the bones of pufferfish, horse mackerel, pig, and chicken as candidates. Protein was measured using the Kendall method according to the standard procedure. In the Kendall method, when the sample is digested at high temperature with a strong acid, carbon is oxidized to carbon dioxide, and nitrogen derived from amino acids forms ammonium sulfate. Ammonium sulfate can be recovered as ammonia by distillation under strong alkaline conditions, and the amount of this ammonia correlates with the constituent amino acids of the protein. The amount of protein contained in the sample is shown in Table 1 below.

[0040] [Table 1]

[0041] As shown in Table 1, the amount of protein in candidate vertebrate bones is approximately 20% by weight. The amount of protein varies depending on the part and species, but it is the same amount of protein as in the flesh or meat of vertebrates. Based on the above results, the backbone of the pufferfish is used as the main ingredient in this example.

[0042] [Protein extraction process] In this example, acetic acid is used as the organic acid. The amount of water is 100 wtf per 100 wtf of pufferfish bone. The concentration of acetic acid is 0.02 wtf (0.02 wt%) per 100 wtf of pufferfish bone. Heating is performed at a temperature of 100 degrees Celsius or higher for 30 minutes. The extraction rate of amino acids and proteins dissolved in the solution (pufferfish bone with acetic acid and water added) can be measured using the Kendall method. In the protein extraction process, protein extraction is enhanced when 0.02 wtf of acetic acid is added compared to when no acetic acid is added (see Figure 2).

[0043] [Protein degradation process] In this example, after cooling the solution from which protein was extracted in the protein extraction process, an acidic proteolytic enzyme, specifically Kokurase, commercially available from Mitsubishi Chemical Corporation, is added, and the protein is decomposed by heating at 50 degrees Celsius for 24 hours. The extraction rate of amino acids and proteins dissolved in the solution can be measured using the Kendall method. The extraction rate of amino acids and proteins when both the protein extraction and proteolytic processes are followed is higher than the extraction rate when only the proteolytic process is followed (see Figure 3). Therefore, in order to extract umami amino acids for fermented foods, both the protein extraction and proteolytic processes are required. [Examples]

[0044] In the method for producing fermented food according to Example 2, the main ingredient is the backbone of the pufferfish, similar to the method for producing fermented food according to Example 1.

[0045] In the protein extraction process, 1000 grams of pufferfish bones are mixed with vinegar containing acetic acid equivalent to 0.1 weight of the bones, and 10 to 20 weight percent, preferably 19 weight percent, of saline solution. The mixture is then heated at 100 degrees Celsius for 15 minutes to extract protein from the pufferfish bones.

[0046] In the protein decomposition process, the solution from which the protein was extracted in the protein extraction process (a mixture of the backbone of the pufferfish with vinegar and saline solution) is cooled to below 60 degrees Celsius. Then, 1.0 gram of the proteolytic enzyme, Kokurase®, and rice koji are added, and the mixture is kept warm at 40 to 60 degrees Celsius. The bones contained in the solution to which Kokurase® and rice koji have been added will break down into small pieces in about 24 hours, so it is preferable to keep the mixture warm until the bones have broken down.

[0047] In the fermentation process, salt-tolerant lactic acid bacteria and yeast are added to the extract hydrolysate obtained from the protein degradation process, and the extract hydrolysate is fermented. The fermentation period in Example 2 was 30 days.

[0048] Since the amount of formol nitrogen increases by the 10th day after adding salt-tolerant lactic acid bacteria and yeast to the extracted hydrolysate (see Figure 4), it can be considered that the protein extracted from the backbone of the pufferfish was converted into lower molecular weight peptides and amino acids by the 10th day after adding salt-tolerant lactic acid bacteria and yeast to the extracted hydrolysate.

[0049] [Amino acid composition] The amino acid composition of the fermented food product (hereinafter referred to as "seasoning from fish bones"), soy sauce, and fish sauce (ishiru) according to Example 2 was measured using an amino acid analyzer (Hitachi High-Tech Science Corporation, high-speed amino acid analyzer AMINO SAAYA LA8080). The results are shown in Table 2 below.

[0050] [Table 2]

[0051] Comparing the total amount of free amino acids in seasonings derived from fish bones, dark soy sauce, and fish sauce (ishiru), seasonings derived from fish bones had 10.0 mass percent of free amino acids, dark soy sauce had about 6.0 mass percent, and fish sauce had about 5.0 mass percent.

[0052] Furthermore, as shown in Table 4, in terms of the composition ratio of free amino acids, the proportion of glutamic acid (Glu) is high in existing dark soy sauce at 18%, while it is slightly lower in seasoning made from fish bones at 14.5%. However, in terms of glutamic acid content in the liquid, seasoning made from fish bones has a higher proportion, resulting in a stronger flavor than existing dark soy sauce. In addition, seasoning made from fish bones has a high proportion of glycine (Gly) and alanine (Ala), which are amino acids that contribute to sweetness, accounting for 20% of the free amino acids. Therefore, based on the analytical values, it can be considered that this seasoning has a pleasant mouthfeel and a refined sweetness.

[0053] [Sensory evaluation] A sensory evaluation was conducted by 10 well-trained panelists. The results showed that the seasoning made from the fish bones was rated as being equivalent to or better than dark soy sauce. In addition, it was commented that, unlike other seasonings, the addition of organic acids lowered the pH, and the acidity acted as a flavor accent. Furthermore, it was commented that it had a strong umami flavor, possessing both the umami of dark soy sauce and the umami of dashi (Japanese broth).

[0054] [Consideration] Umami-rich seasonings like soy sauce prevent microbial contamination by increasing their salt content. On the other hand, seasonings made from fish bones (fermented foods) have a low pH due to the addition of organic acids, and microbial contamination is prevented by heating. As a result, they can be used as seasonings and foods with low salt content, no dilution required, and a strong umami flavor. Sensory evaluations also show that these fermented foods have an enhanced umami flavor.

[0055] [comprehensive evaluation] As is clear from the results above, the seasoning (fermented food) made from bones has a strong umami flavor and is very aromatic. This was supported by component analysis, amino acid content, and sensory evaluation. There have been few examples of fermented foods developed using bones as the main ingredient. Furthermore, while fish bones tend to have a fishy smell, or animal bones tend to have a strong animal smell, heating with organic acids eliminates the distinctive odor, resulting in a fermented food that is different from conventional fish sauce, pork bone broth, or chicken broth, and has been evaluated as high quality.

[0056] The present invention is not limited to the embodiments described above, and includes modified forms of the embodiments described above, as well as forms that combine these forms as appropriate. [Explanation of Symbols]

[0057] 11 Main raw materials 12 Organic acids 13 water 14. Proteolytic enzymes 15 Koji 16 Lactic acid bacteria 17 Yeast 18 Pressed pulp 19. Pressed liquid

Claims

1. A method for producing fermented foods using vertebrate bones as the main ingredient, A protein extraction step is performed by adding an organic acid and water to the main raw material and heating it to extract protein from the main raw material. A protein degradation step is performed by adding at least one of a proteolytic enzyme or koji to the protein extracted in the protein extraction step to degrade the protein, In the protein degradation step, at least one of lactic acid bacteria or yeast is added to the extract hydrolysate obtained by the protein degradation step, and a fermentation step is performed to ferment the extract hydrolysate. A method for producing fermented foods, comprising the same characteristics.

2. The method for producing a fermented food according to claim 1, wherein the heating in the protein extraction step is continued at a temperature of 100 degrees Celsius or higher for 10 minutes or more.

3. The method for producing a fermented food according to claim 1, wherein the concentration of the organic acid is 0.01 weight-force or more and 0.10 weight-force or less, when the main raw material is 100 weight-force.

4. The method for producing a fermented food according to claim 1 or 3, wherein the organic acid is acetic acid.

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