Method for producing fermented food of fish

Abstract

An object of the present invention is to produce a fermented food using fish offal as a raw material by simply adjusting the fermentation temperature without adding salts. 【Solution means】In order to effectively reduce the unpleasant odor of fish and the bitterness of fish offal, and to ferment fish offal without adding any salt and increase the umami flavor, the present invention divides the fermentation process into two stages. In the primary fermentation process, low-temperature fermentation is carried out at 35°C to 45°C, and in the secondary fermentation process, high-temperature fermentation is carried out at 55°C to 70°C. It is a method for producing a fermented food characterized by this.

Description

Technical Field

[0001] The present invention relates to a method for producing a fermented food using fish viscera without adding salt.

Background Art

[0002] The edible part of a fish accounts for about 50% (the proportion of viscera is about 3 - 10%), and a large amount of residue is discharged. Fishery residues mainly refer to residues centered on food waste generated in the series of distribution processes from the landing of fishery products to consumption. Since they contain useful components such as protein, they have high potential as "resources". However, on the other hand, when disposed of as "garbage", there is a two-sided nature in that the cost required for its collection and treatment is large.

[0003] Fishery residues are generated at the landing stage in primary processing at the production area market etc. (such as scaling or removing the head), the pretreatment process of processed raw fish, and primary processing at the aquaculture production area (filleting or removing the viscera part, etc.). Fishery residues generated at these stages generally have good freshness because the fish immediately after landing is often utilized, and they are also easy to collect quantitatively. Focusing on this point, it is required to reduce fishery waste, which is fishery residues, and utilize useful components such as protein so that they can be edible.

[0004] In particular, fish viscera are rich in vitamin A, calcium, minerals, DHA, and EPA that prevent adult diseases. However, there is a problem that an unpleasant odor and bitterness derived from the viscera are felt, and from the viewpoint of delicious eating, the conventional processing methods are not sufficient. Various treatment methods have been proposed for the purpose of solving the fishy smell.

[0005] For example, fish sauce and nam pla can be mentioned as seasonings obtained by fermenting fish offal or viscera. However, in order to prevent contamination by microorganisms, it is necessary to add a high concentration of salt (more than 10 - 20%), making it difficult for endogenous enzymes (visceral enzymes) to function. As a result, it takes a long fermentation time, such as heating the product fermented at room temperature for 1 - 3 years and then performing primary filtration and secondary filtration for production. Thus, the conventional method has problems such as the need for salt addition and long - term fermentation, and the resulting unique taste and aroma.

[0006] Therefore, Patent Document 1 discloses a method for making fish sauce in a short time by fermenting mackerel viscera and body parts without adding salt at 40°C or higher for 1 hour or more, adding salt to 10% or more or adding acidic food to make the pH 5 or lower after fermentation, performing heat treatment, and filtering to obtain a clarified liquid.

[0007] According to this method, by including a fermentation step without adding salt, it is possible to ferment while suppressing the growth of miscellaneous bacteria and without inhibiting the activity of proteolytic enzymes derived from raw fish and shellfish, thereby shortening the fermentation time. However, in the second - stage fermentation process, in order to prevent contamination by microorganisms, a high concentration of salt (10% or more) is added, resulting in the problem that endogenous enzymes (visceral enzymes) have difficulty functioning.

[0008] Also, Patent Document 2 discloses a method for manufacturing a processed fish product that shortens the period required for fermentation by seasoning including salting by subjecting a fish meat material to a medium - high pressure treatment under relatively low pressure conditions of less than 100 MPa to disrupt cell membranes.

[0009] However, the method disclosed in Patent Document 2 does not include the processing of viscera, and there is a problem that equipment for medium - high pressure treatment under relatively low pressure conditions of less than 100 MPa is required.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0011] Therefore, in view of the above problems, an object of the present invention is to provide a method for producing a fermented food using fish offal as a raw material, which can produce a fermented food by adjusting the fermentation temperature only without adding salt.

Means for Solving the Problems

[0012] The present invention takes the following technical means to solve the above problems.

[0013] The method for producing a fermented food from fish according to the present invention is A method for producing a fermented food without adding salt and using fish offal, A primary fermentation step of fermenting fish offal with an emulsifier added at 35 to 45 °C for 4 to 8 hours, A secondary fermentation step of fermenting the fermentation broth obtained in the primary fermentation step at 55 to 70 °C for 18 to 42 hours, characterized by performing the above steps.

[0014] In addition, the inventor of the present application has clarified that oil can be efficiently separated from fish offal by exactly the same method as the method for producing a fermented food from fish. That is, the method for separating oil from fish offal according to the present invention is A primary fermentation step of fermenting fish offal with an emulsifier added at 35 to 45 °C for 4 to 8 hours, A secondary fermentation step of fermenting the fermentation broth obtained in the primary fermentation step at 55 to 70 °C for 18 to 42 hours, characterized by performing the above steps.

Effects of the Invention

[0015] It is possible to produce a fermented food with less trimethylamine (TMA) that causes fishy odor and effectively reduces the bitterness of internal organs. In addition, by performing salt-free high-temperature fermentation, it is possible to produce a fermented food with an increased content of free amino acids (total FAA), excellent preservability, and low hygroscopicity.

Brief Description of the Drawings

[0016]

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Embodiments for Carrying Out the Invention

[0017] The present invention effectively reduces the unpleasant odor of fish and the bitterness of fish internal organs, and ferments fish internal organs without adding any salt to increase umami. To this end, the fermentation process is divided into two stages. A low-temperature fermentation at 35°C to 45°C is performed in the primary fermentation process, and a high-temperature fermentation at 55°C to 70°C is performed in the secondary fermentation process. It is a method for producing a fermented food characterized by this. In particular, in order to increase the fermentation efficiency in a short time, a food emulsifier is added in the low-temperature primary fermentation process. In addition, by performing treatments such as centrifugation after the fermentation process, it is possible to efficiently release the oil content (hereinafter referred to as "fish oil") contained in fish internal organs and fish fillets, and it is possible to obtain fish oil relatively inexpensively, simply, and safely.

[0018] For the viscera and minced meat of fish, those removed from the fish body can be used, and residues can also be used. Relatively medium-sized to large fish are preferred, such as catfish (American catfish, Pangasius, etc.), salmon (golden trout, coho salmon, etc.), cod (Alaska pollock, hake, merluccius, etc.), herring (sardine, pilchard, etc.), flying fish (saury, flying fish, etc.), sea bream, flounder (black rockfish, gindara, etc.), sea bass (tuna, amberjack, juvenile tilapia, Nile tilapia, Japanese sea bass, yellowtail, striped jack, horse mackerel, skipjack tuna, red sea bream, Japanese grunt, etc.), flatfish (halibut, olive flounder, black rock sole, etc.).

[0019] "Viscera" means the viscera of fish, and examples include the stomach, pyloric caeca, intestine, and liver. Since these viscera contain digestive enzymes such as amylase, protease, and lipase, they can be preferably used for fermentation. "Minced meat" means the fish meat remaining on the skin and bones when the skin and fish meat are cut from the fish body, as well as the scraps such as the head and bones. These viscera and minced meat are used as "fermentation materials".

[0020] "Fish oil" means the oil contained in the viscera and minced meat of fish before fermentation. It is desirable that the viscera and minced meat have a fat content of 10% or more, and preferably 30% or more.

[0021] "Food emulsifier" (hereinafter simply referred to as "emulsifier") means an emulsifier whose use is permitted by the Food Sanitation Law. Examples of synthetic emulsifiers include glycerin fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, and propylene glycol fatty acid esters. Examples of natural emulsifiers include phospholipids (lecithin) and casein. The amount of the emulsifier added to the fermentation material is preferably less than 3%, more preferably 0.01 - 0.5%, based on the weight of the fermentation material.

[0022] When using the "emulsifier", water is added to the fermentation material. The amount of water added is preferably less than 200%, more preferably 20 - 50%, based on the weight of the fermentation material.

[0023] "Fermented food" means food obtained through the fermentation process and is not limited to specific foods. From the perspectives of food preservation and utilization, those that have undergone processes such as powdering and granulation are also included. For high-salt fermented foods, since the enzyme activity decreases and fermentation takes a long time, in this example, fermentation is carried out without adding salt. When no salt is added, there is a problem that miscellaneous bacteria are likely to multiply, so fermentation is carried out at a high temperature to prevent the multiplication of miscellaneous bacteria.

[0024] Fermentation is carried out in two stages: a primary fermentation process at a low temperature (35°C - 45°C) and a secondary fermentation process at a high temperature (55°C - 70°C). In particular, in the primary fermentation process, an emulsifier is added.

[0025] In the primary fermentation process, fermentation is carried out at a low temperature of 35°C - 45°C because the temperature range of 35°C - 45°C is the temperature range in which lipase contained in the internal organs of the fermentation material shows suitable activity. By utilizing this, the separation of fish oil from the fermentation material is promoted, so fermentation is carried out in this temperature range. The reason for adding an emulsifier in the primary fermentation process is to attach the emulsifier to the fat (fish oil) on the surface of the internal organs, which are the fermentation material, so that the lipase contained in the internal organs of the fermentation material can act advantageously on the separation and decomposition of fish oil.

[0026] Also, in order to effectively exert this effect, from the results of the inventor's previous research, it is known that fermentation for 4 hours or more is required in the primary fermentation process. However, since microbial contamination (increase in general viable bacteria) is a concern when fermenting for 8 hours or more, the fermentation time in the primary fermentation step is preferably 4 to 8 hours.

[0027] In the secondary fermentation step, fermenting at a high temperature of 55°C to 70°C is because the temperature range of 55°C to 70°C is the temperature range in which the protease contained in the internal organs of the fermentation material shows suitable activity. Therefore, in order to utilize this and promote the decomposition of the protein in the fermentation material into amino acids, it was decided to ferment in this temperature range. In addition, performing the high-temperature fermentation step after the low-temperature fermentation step is because the fat (fish oil) on the surface of the internal organs is removed from the fermentation material by the low-temperature primary fermentation step. Therefore, in the high-temperature secondary fermentation step, the protease can more easily approach the protein in the internal organ tissue, and the decomposition of the protein into amino acids is further promoted.

[0028] Also, in order to effectively exert this effect, from the results of the inventor's previous research, it is known that the secondary fermentation step requires fermentation for 18 hours or more. However, it has also been found that fermenting for 42 hours is sufficient to exert this effect, and there is no concern about microbial contamination (increase in general viable bacteria) up to 92 hours. Therefore, the fermentation time in the secondary fermentation step is preferably 18 to 42 (or 92) hours.

[0029] The centrifugation treatment step is preferably carried out after the fermentation step. The centrifugation treatment can be carried out, for example, at 1000 to 10000 rpm using a batch centrifuge, and preferably at 3000 to 6000 rpm. The treatment time is about 10 to 60 minutes, and preferably about 20 to 40 minutes. As a result, the fish oil is more clearly separated from the fermentation treatment liquid (aqueous layer and oil layer). Therefore, only the fish oil can be easily obtained from the fermentation treatment liquid by methods such as decanting the upper phase, scooping it up with a container, or suction sampling.

[0030] The present invention will be described in detail based on the following examples. Example 1 is a method for producing a fermented food. Example 2 is a method for producing fish oil. Example 3 is a method for producing a fermented food and fish oil. In any of the examples, as a fermentation material, a mixture of the internal organs and fillets of the Japanese sea bass (Lateolabrax japonicus) was used. In the following description, unless otherwise specified, “%” means “mass %”.

[0031] (Example 1) The Japanese sea bass was processed to remove the internal organs and fillets, and these were lightly washed with water without separation. 1000 - 2000 g of the fermentation material obtained by mixing the internal organs and fillets, 0.1% of soy lecithin (emulsifier) based on the weight of the fermentation material, and 30% of tap water were placed in a large transparent round bottle (10000 ml, manufactured by Nalgene), and this was fermented at 60°C for 24 hours in a constant temperature bath. The unfermented treatment liquid (at the 0 - hour mark) was designated as Sample 1, and the fermented treatment liquid obtained by fermenting for 24 hours was designated as Sample 2. Also, under the same conditions, the fermented treatment liquid obtained by fermenting for 24 hours without adding soy lecithin (without emulsifier) was designated as Sample 3.

[0032] Figure 1 is a graph showing the measurement results of the total free amino acid content of Sample 1 (unfermented treatment liquid), Sample 2 (fermented treatment liquid after 24 hours, with emulsifier), and Sample 3 (fermented treatment liquid after 24 hours, without emulsifier) obtained in Example 1. The measurement of the total free amino acid content was carried out by a post - column fluorescence derivatization method using high - performance liquid chromatography (Prominence, manufactured by Shimadzu Corporation).

[0033] As shown in Figure 1, the total free amino acid content of Sample 2 increased by approximately 8.9 times compared to Sample 1. However, the total free amino acid content of Sample 3 increased by only approximately 3.1 times compared to Sample 1. The amino acid content of each obtained sample (fermentation treatment liquid) was about 3 to 10 times that before fermentation.

[0034] The fermentation treatment liquid can be eaten as a savory fermented food. The fermentation treatment liquid can be used as a food in its liquid state. However, by further spray-drying or freeze-drying to powderize it, and even granulating it, the food preservation and versatility can be enhanced. Known methods can be used for the powderization and granulation of the fermentation treatment liquid. That is, for powderization and granulation, one kind and / or a combination of two or more kinds of conventionally used additives can be used.

[0035] Examples of the additives include excipients, binders, disintegrants, lubricants, fluidizing agents, coating agents, flavor correctives, masking agents, fragrances, and antioxidants. Moreover, as the powder machine used in the formulation process, a spray dryer, a freeze dryer, etc. can be mentioned, and as the granulator, a planetary mixer, a stirring granulator, a high-speed mixing granulator, an extrusion granulator, a fluidized bed granulator, a centrifugal rolling fluidized granulator, a roller compactor, etc. can be mentioned. The obtained powders and granules can also be used for solid foods such as granule soup and instant soup. Also, it can be used by the usual method in combination with food materials, food additives, etc. according to the food.

[0036] (Example 2) Cut the horse mackerel, remove the internal organs and the lean meat, and gently wash them without separating them. Put 2000 g of the fermentation material obtained by mixing the internal organs and the lean meat, 0.1% of soy lecithin, and 30% of city water with respect to the weight of the fermentation material into a large transparent round bottle (10,000 ml, manufactured by Nalgene), and ferment this in a constant temperature and humidity chamber. The fermentation in this constant temperature and humidity chamber was carried out as follows: The fermentation treatment liquid that was first fermented at 40°C for 6 hours was designated as Sample 4, and the fermentation treatment liquid that was first fermented at 40°C for 6 hours and then further fermented at 60°C for 6 hours was designated as Sample 5. Also, under the same fermentation conditions as Samples 4 and 5, the fermentation treatment liquids obtained by fermenting without adding soy lecithin (without emulsifier) were designated as Sample 6 and Sample 7, respectively.

[0037] The fish oil obtained by decanting the upper layer of these samples (fermentation treatment liquids) was measured as the crude fat content of each sample. The measurement of the crude fat content was carried out by adding a chloroform-methanol mixed solvent (volume ratio 2:1, hereinafter referred to as "CM mixture") and water, each in an amount five times the volume of the sample, to each sample, followed by liquid-liquid partitioning in a separating funnel to obtain the upper layer (organic solvent layer). The upper layer obtained by washing the upper layer twice with an equal volume of 10% sodium sulfate aqueous solution was concentrated under reduced pressure using a rotary evaporator. Thereafter, it was dried in a constant temperature dryer at 105°C for 1 hour and weighed to obtain the crude fat content (fish oil content) of each sample.

[0038] Figure 2 is a graph showing the measurement results of the crude fat content of Sample 4 (fermentation treatment liquid at 40°C after 6 hours, with emulsifier), Sample 5 (fermentation treatment liquid at 40°C for 6 hours and then at 60°C for 6 hours, with emulsifier), Sample 6 (fermentation treatment liquid at 40°C after 6 hours, with emulsifier), and Sample 7 (fermentation treatment liquid at 40°C for 6 hours and then at 60°C for 6 hours, without emulsifier), obtained in Example 2. As shown in Figure 2, the crude fat content (fish oil content) of Sample 6 was only about 1 / 8 of that of Sample 4. The crude fat content (fish oil content) of Sample 7 was also only about 1 / 8 of that of Sample 5. However, the crude fat content (fish oil content) of Sample 4 was 2.5 times that of Sample 5.

[0039] The fish oil contained in the fermentation treatment liquid is mainly composed of highly unsaturated fatty acids decomposed by the action of visceral-derived lipolytic enzymes. Since this fish oil has a lower specific gravity than the fermentation treatment liquid, it is separated into the upper phase of the fermentation treatment liquid simultaneously with the completion of fermentation. Therefore, only the fish oil can be easily obtained from the fermentation treatment liquid by methods such as decantation, skimming, or suction sampling of the upper phase. However, when the interface between the upper phase (fish oil) and the lower phase (fermentation treatment liquid) is unclear or when it is difficult to separate the upper phase, for example, the following heating treatment step and centrifugation treatment step can be carried out.

[0040] (Example 3) The horse mackerel is processed and its internal organs and fillets are removed, and they are lightly washed with water without separation. 2000 g of the fermentation material obtained by mixing the internal organs and fillets, 0.1% of soy lecithin based on the weight of the fermentation material, and 30% of city water are placed in a large transparent round bottle (10,000 ml, manufactured by Nalgene), and this is fermented in a constant temperature bath. The fermentation in this constant temperature bath was carried out at 25°C for 96 hours, and the fermentation treatment liquid at this time was designated as fermentation treatment 1, and the fermentation treatment liquid at 60°C for 96 hours was designated as fermentation treatment 2. Also, the same preparation was carried out using the above-mentioned fermentation material, and after primary fermentation at 40°C for 6 hours in a constant temperature bath, the fermentation treatment liquid when the temperature was raised to 60°C and secondary fermentation was carried out for 96 hours was designated as fermentation treatment 3.

[0041] Figure 3 is a graph showing the transition of the total free amino acid content of fermentation treatments 1 to 3 obtained in Example 3. The measurement of the total free amino acid content was carried out by the same operation as in Example 1. As shown in Figure 3, in fermentation treatment 1 (×), even after 96 hours of fermentation, the increase was only about 2.7 times compared to the total free amino acid amount before fermentation. In fermentation treatment 2 (▲), compared to the total free amino acid amount before fermentation, it increased by about 9.1 times after 24 hours of fermentation and about 14 times after 96 hours. On the other hand, in fermentation treatment 3 (〇), compared to the total free amino acid amount before fermentation, it showed an increase of about 14 times after 24 hours of fermentation and remained at the same total free amino acid amount until 96 hours.

[0042] Figure 4 is a graph showing the transition of the crude fat content in fermentation treatments 1 to 3 obtained in Example 3. The measurement of the crude fat content was carried out in the same manner as in Example 2. As shown in Figure 4, in fermentation treatment 2 (▲), compared with fermentation treatment 1 (×), the crude fat content increased by about 6 times in 24 hours of fermentation and about 10 times in 96 hours. On the other hand, in fermentation treatment 3 (〇), compared with fermentation treatment 1, the crude fat content showed an increase of about 14 times in 24 hours of fermentation and remained at the same crude fat content until 96 hours.

[0043] Figure 5 is a graph showing the measurement results of the viable count of general bacteria in fermentation treatments 1 to 3 obtained in Example 3. The measurement of the viable count of general bacteria was carried out by smearing the fermentation treatment solutions of fermentation treatments 1 to 3 (48 hours after the start of fermentation in the primary fermentation process), appropriately diluted with sterilized physiological saline, on the surface of a standard agar medium, and then culturing in a constant temperature bath at 35°C for 48 hours.

[0044] The number of colonies formed on the medium after culturing was counted, and the viable count of bacteria per 1 ml of the fermentation treatment solution (CFU / ml) was calculated and used as the viable count of general bacteria for each sample. Note that when the viable count of general bacteria per 1 ml of the fermentation treatment solution is 3000 CFU or more, it is an undesirable state as a food, when it is less than 3000 CFU, it is an acceptable state as a food, and when it is 300 CFU or less, it indicates a clean and hygienic state.

[0045] As shown in Figure 5, in fermentation treatment 1, the viable count of bacteria per 1 ml of the fermentation treatment solution was 56000 CFU, which was an undesirable state as a food. In fermentation treatments 2 and 3, the viable count of bacteria per 1 ml of the fermentation treatment solution was 300 CFU or less, which was a clean and hygienic state.

[0046] From the above results, in order to produce a fermented food using fish viscera without adding salt and separate the oil content of the fish during the process, in the primary fermentation step of adding an emulsifier and fermenting, fermentation should be carried out at 35°C to 45°C for 4 to 8 hours. Furthermore, in the secondary fermentation step of changing the fermentation temperature and fermenting, it is optimal to carry out fermentation at 55°C to 70°C for 18 to 42 (or 92) hours.

Claims

1. A method for producing a fermented food using fish viscera without adding salt, comprising: a primary fermentation step of fermenting fish viscera with an emulsifier added thereto at 35 to 45 °C for 4 to 8 hours; a secondary fermentation step of fermenting the fermentation broth obtained in the primary fermentation step at 55 to 70 °C for 18 to 42 hours; A method for producing a fermented food, characterized by performing the above steps.

2. A method for producing a fermented food using fish viscera without adding salt, comprising: a primary fermentation step of fermenting fish viscera with an emulsifier added thereto at 40 °C for 6 hours; a secondary fermentation step of fermenting the fermentation broth obtained in the primary fermentation step at 60 °C for 42 hours; A method for producing a fermented food, characterized by performing the above steps.

3. A method for producing a fermented food using fish viscera without adding salt, comprising: a primary fermentation step of fermenting fish viscera with phospholipids added thereto at 40 °C for 6 hours; a secondary fermentation step of fermenting the fermentation broth obtained in the primary fermentation step at 60 °C for 42 hours; A method for producing a fermented food, characterized by performing the above steps.

4. A method for producing a fermented food using fish viscera without adding salt, comprising: a primary fermentation step of fermenting fish viscera with 0.01 to 0.5% phospholipids based on the weight of the fermentation material added thereto at 40 °C for 6 hours; a secondary fermentation step of fermenting the fermentation broth obtained in the primary fermentation step at 60 °C for 42 hours; A method for producing a fermented food, characterized by performing the above steps.

5. A method for separating oil from fish viscera, comprising: a primary fermentation step of fermenting fish viscera with an emulsifier added thereto at 35 to 45 °C for 4 to 8 hours; a secondary fermentation step of fermenting the fermentation broth obtained in the primary fermentation step at 55 to 70 °C for 18 to 42 hours; A method for separating oil from fish viscera, characterized by performing the above steps.

6. A method for separating oil from fish viscera, comprising: a primary fermentation step of fermenting fish viscera with an emulsifier added thereto at 40 °C for 6 hours; a secondary fermentation step of fermenting the fermentation broth obtained in the primary fermentation step at 60 °C for 42 hours; A method for separating oil from fish viscera, characterized by performing the above steps.

7. A method for separating oil from fish viscera, comprising: a primary fermentation step of fermenting fish viscera with phospholipids added thereto at 40 °C for 6 hours; a secondary fermentation step of fermenting the fermentation broth obtained in the primary fermentation step at 60 °C for 42 hours; A method for separating oil from fish viscera, characterized by performing the above steps.

8. A method for separating oil from fish viscera, comprising: A primary fermentation step of adding 0.01 to 0.5% phospholipid based on the weight of the fermentation material to the internal organs of fish and fermenting at 40°C for 6 hours, A secondary fermentation step of fermenting the fermentation broth obtained in the primary fermentation step at 60°C for 42 hours, A method for separating fish oil, characterized by performing the above steps.

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