Low-salt low-odor fish sauce and method for producing the same

Abstract

To provide a fish sauce having reduced unpleasant odor and having a low salt concentration.SOLUTION: In a previously prepared Shirakami Kodama yeast fermentation liquid, a marine product or marine product waste is subjected to autolysis at a high temperature of 45°C or higher, enabling the production of a fish sauce with a salt content of 8% or less and a value of total nitrogen% / salt% of 0.20 or more, as well as fish oil and an emulsifying component.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a fish sauce produced by liquefying the fish through autolysis in a fermentation liquid previously fermented with yeast, to the fish oil and emulsifying component produced in the process, and to a processed food containing the fish sauce, fish oil, and emulsifying component. [Background technology]

[0002] Fish sauce, a seasoning made by digesting seafood either by autolysis or with an enzyme preparation, has a strong umami flavor mainly derived from amino acids and is therefore widely used in food products not only in Japan but also in Southeast Asia and Europe as an umami seasoning.

[0003] In Japan, shottsuru is produced in Akita Prefecture, ishiru in Ishikawa Prefecture, and overseas, fish sauces such as nam pla in Thailand, nuoc nam in Vietnam, and garum in Italy are produced and used in a wide range of regions.

[0004] The characteristics of these fish sauces are that they are umami seasonings with a high amino acid concentration, as mentioned above. When seafood proteins are decomposed by autolysis or enzyme digestion, there is a risk of microbial spoilage and the production of the harmful substance histamine at low salt concentrations. In addition, the size of the seafood that is the subject of decomposition is larger than that of grain sauces such as soy sauce, which are made from grains, and it takes a long time for the salt to penetrate the subject of decomposition. For these reasons, it is a flavor seasoning with a higher salt concentration than grain sauces.

[0005] Although fish sauce is a flavor enhancer that differs from grain sauce, its use in food is limited due to its high salt concentration and the strong, unpleasant odors inherent in it, such as propionic acid, butyric acid, and isovaleric acid.

[0006] As such, the high salt concentration and strong, distinctive odor of fish sauce are barriers to its widespread use, and various technologies have been developed to reduce the salt content and unpleasant odor.

[0007] To reduce odors, methods have been devised, including a method in which fish is ground up, salt is added, and the resulting mixture is stirred uniformly and then digested with an enzyme (Patent Document 1, JP 2003-199523), since slow salt penetration is one factor in the generation of unpleasant odors. Another method, in which the digested fish sauce is heated at high temperatures, then dried and powdered (Patent Document 2, JP 2003-47433), removes the unpleasant odors produced. These methods are difficult to remove, and some unpleasant odors remain. Furthermore, because soybean soy sauce, a grain sauce, has deodorizing properties and a fragrant aroma, a method has been developed in which soybean soy sauce is added immediately after the production of salt-free fish sauce to achieve a salt concentration of 7 to 10% (Patent Document 3). However, the deodorizing effect is limited when the soy sauce content is low. Conversely, increasing the soy sauce content to enhance the deodorizing effect increases the salt concentration to nearly 10%, reducing the umami (seafood-derived flavor) characteristic of fish sauce.

[0008] Furthermore, methods for producing fish sauce in which seafood is digested in the presence of alcohol, such as an organic acid-containing alcohol aqueous solution (Patent Documents 4 and 5) or sake lees (Patent Document 6), are known to reduce unpleasant odors, but these methods also have difficulty reducing the wide variety of unpleasant odors.

[0009] Several methods have been developed to reduce unpleasant odors by utilizing microbial fermentation. A method using specific bacteria belonging to the genus Staphylococcus (Patent Document 7) is effective in reducing unpleasant odors, but the high salt concentration slows fermentation, making it take a long time to reduce the odor and extending the production period.

[0010] Several methods utilizing yeast fermentation have been developed as a method for efficiently reducing unpleasant odors by utilizing the deodorization of microbial fermentation products and the alcohol produced by fermentation. Patent Document 7 describes a method for producing fish soy sauce, which involves adding an enzyme solution to seafood, digesting it at high temperature, adding lactic acid bacteria, yeast, and rice koji, and then adjusting the salt content to produce a mash, which is then decomposed, fermented, and matured. Patent Document 8 describes a method for producing fish soy sauce, which involves adding salt, water, and halotolerant lactic acid bacteria to seafood raw materials, mixing this, adding solid koji, and mixing the resulting mash. Immediately after preparation, the mash is heated and the halotolerant yeast Zygosaccharomyces ruxii is added, and the mash is fermented and matured in a short period of time. Patent Document 9 describes a method for producing fish soy sauce in which water, salt, and koji are added to the raw material krill during brewing, followed by the addition of halotolerant lactic acid bacteria and halotolerant yeast, and the resulting mash is then fermented and matured. Patent Document 10 describes a method for producing a rich, flavorful fish soy sauce, characterized by producing koji from raw materials that have been pressurized, heated, and expanded using an extruder. The method uses halotolerant lactic acid bacteria and halotolerant yeast, and involves fermenting the mash at a low temperature of less than 15°C for at least one month after brewing, followed by a long-term fermentation and maturation at a low temperature of less than 20°C. Patent Document 11 describes a method for producing fish soy sauce in which salt and koji are added to seafood during brewing, followed by the addition of halotolerant lactic acid bacteria and halotolerant yeast, and the resulting mash is then fermented and matured at a low temperature. These techniques involve yeast fermentation during digestion to reduce unpleasant odors, but because the mash has a high salt concentration, all of the yeast used is halotolerant yeast, as used in miso and soy sauce brewing. Fermentation using salt-tolerant yeast requires a long period of time, and the alcohol concentration produced is only about 3%, so the effect of reducing unpleasant odors is limited.

[0011] In addition, a technology has been developed that uses the same salt-tolerant yeast but ferments at a low salt concentration to increase the content of 4-hydroxy-2-ethyl-5-methyl-3(2H)-furanone or 4-hydroxy-5-ethyl-2-methyl-3(2H)-furanone, which are aroma components specifically produced by the salt-tolerant yeast (Patent Document 12). However, the deodorizing effect of these aroma components is low, and alcohol production remains suppressed even at low salt concentrations.

[0012] Furthermore, there are known techniques for producing fish sauce at a low salt concentration and high temperature to promote digestion in order to reduce unpleasant odors and suppress the generation of unpleasant odors themselves (Patent Document 13), and a technique that combines this technique with yeast fermentation (Patent Document 14), but these require the addition of water to seafood and long-term fermentation.

[0013] Known techniques for producing fish sauce with a low salt concentration include methods for producing fish sauce with a salt concentration of less than 5% by weight (Patent Documents 15 and 16), but no measures are taken to reduce unpleasant odors.

[0014] In order to produce alcohol through yeast fermentation and reduce the unpleasant odors caused by this alcohol, the use of salt-tolerant yeast has been promoted because digestion is carried out at high salt concentrations as mentioned above. However, since the alcohol production ability of salt-tolerant yeast is low and the production amount is limited to about 3%, a technology has also been developed in which mash is fermented with baker's yeast, which has a higher alcohol production ability (Patent Document 17). Since it is difficult to rapidly increase the alcohol concentration in the mash even with baker's yeast, this technology uses a salt concentration of 8 to 18% by weight to prevent early spoilage. Since alcohol fermentation with baker's yeast, which has low salt tolerance, is strongly inhibited, the amount of alcohol produced is low and the effect of reducing unpleasant odors is low.

[0015] Furthermore, a known method for producing fish sauce with reduced unpleasant odors that combines all of the above technologies involves using seafood, salt, and koji as ingredients, and using all three types of microorganisms - salt-tolerant lactic acid bacteria, Zygosaccharomyces yeast, and Candida yeast - in combination to ferment the moromi mash while heating it to 30-40°C (Patent Document 18).This technology is expected to be highly effective in reducing unpleasant odors, but because it requires the addition of a certain concentration of salt to prevent spoilage in the early stages of fermentation, vigorous alcoholic fermentation and high digestibility of the seafood as raw materials cannot be expected, making it difficult to sufficiently reduce unpleasant odors and shorten the production period. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-199523 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-47433 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-1208987 [Patent Document 4] Japanese Patent Application Laid-Open No. 2006-280280 [Patent Document 5] Japanese Patent Application Publication No. 11-221043 [Patent Document 6] Japanese Patent Application Laid-Open No. 2005-87016 [Patent Document 7] Japanese Patent Application Publication No. 11-318383 [Patent Document 8] Japanese Patent Application Laid-Open No. 2002-191321 [Patent Document 9] Japanese Patent Application Laid-Open No. 2000-295971 [Patent Document 10] Japanese Patent Application Publication No. 9-191850 [Patent Document 11] Japanese Patent Application Publication No. 8-256727 [Patent Document 12] Japanese Patent Publication No. 2022-73492 [Patent Document 13] Japanese Patent Application Laid-Open No. 2015-223178 [Patent Document 14] Japanese Patent Application Publication No. 11-318383 [Patent Document 15] Japanese Patent Application Publication No. 2017-216898 [Patent Document 16] Japanese Patent Application Laid-Open No. 2015-223178 [Patent Document 17] Japanese Patent Application Laid-Open No. 2011-120484 [Patent Document 18] Japanese Patent Application Laid-Open No. 2004-313138 Summary of the Invention [Problem to be solved by the invention]

[0017] Fish sauce, which is made by autolysis or enzymatic digestion of seafood, has a distinctive unpleasant odor, and for the purposes of preservation and preventing the production of harmful substances, it is digested under high salt concentrations. Due to this odor and high salt concentration, the use of fish sauce in processed foods has been limited in terms of both how and how much it can be used. For these reasons, food manufacturers and consumers have been seeking fish sauce with a reduced unpleasant odor and low salt content.

[0018] Therefore, the objective was to develop a fish sauce with reduced unpleasant odor and low salt concentration. [Means for solving the problem]

[0019] The present inventors discovered that high-temperature autolysis of seafood or seafood processing waste is promoted by using salt-free or low-salt solutions, that it is necessary to achieve uniformity in the reaction system in a short time to prevent the generation of unpleasant odors and spoilage, and that high-temperature autolysis in a solution is preferable for this purpose, that a yeast fermentation liquid prepared in advance using yeast with high alcohol-producing ability is optimal as the solution to be used, and that the autolysis temperature is optimally 45°C or higher, leading to the completion of the present invention.

[0020] Furthermore, the inventors have newly discovered that high-temperature autolysis of seafood or seafood waste in a yeast fermentation liquid can safely digest fish and shellfish even when the salt content of the autolysis system is 8% or less, and that the low salt content promotes autolysis, and that the resulting fish sauce, despite being diluted with the yeast fermentation liquid, has a strong amino acid flavor and a value of total nitrogen % / salt concentration %, an index of amino acid concentration, of 0.20 or more, thereby completing the present invention.

[0021] According to the Ministry of Education, Culture, Sports, Science and Technology's food composition database, the total nitrogen % / salt concentration % values ​​listed for fish sauces are 0.064 for fish sauce, 0.040 for shottsuru, 0.105 for sand lance soy sauce, and 0.094 for ishiri. The soy sauce with the highest value is low-salt dark soy sauce, which is 0.171.

[0022] Furthermore, while yeast fermentation can reduce unpleasant odors, we have newly discovered that Shirakami Kodama yeast, a bread yeast, is ideal for use in the pre-prepared fermentation liquid, as it not only reduces unpleasant odors but also improves shelf life in low-salt or salt-free environments, leading to the completion of this invention.

[0023] Furthermore, the inventors have newly discovered that the fish oil and emulsifying components are separated from the fish sauce by the self-digestion of seafood or seafood processing waste, and that they can be separated and retain usable quantities and quality; in particular, the fish oil has no oxidized odor, retains the structure that was present in the seafood, and is in an unoxidized state, leading to the completion of the present invention.

[0024] Furthermore, we have newly discovered that good processed foods can be produced by blending fish sauce produced by the autolysis of seafood or seafood processing waste, its dried product, fish oil, and emulsifying ingredients, and have completed the present invention.

[0025] The present invention provides the following (1), (2), (3), (4), and (5). (1) To provide a method for producing fish sauce, characterized by subjecting seafood or seafood waste to autolysis at a high temperature of 45°C or higher in a pre-prepared yeast fermentation liquid. (2) To provide the fish sauce and its dried product according to (1) above, characterized in that the salt content is 8% or less and the ratio of total nitrogen % / salt % is 0.20 or more. (3) To provide a method for producing fish sauce, characterized in that the yeast described in (1) above is Shirakami Kodama yeast. (4) To provide a fish oil and an emulsified component that are produced during the production of the fish sauce described in (1) above. (5) To provide a processed product characterized by blending the fish sauce or its dried product, fish oil or emulsified component described in (2) or (4) above. [Effects of the Invention]

[0026] According to the present invention, by subjecting seafood or seafood processing waste to high-temperature autolysis in a short period of time in a yeast fermentation liquid fermented with a pre-prepared Shirakami Kodama yeast or the like, it is possible to produce a fish sauce with a reduced unpleasant odor and a rich flavor, with a salt content of 8% or less and a total nitrogen % / salt % ratio of 0.20 or more, and at the same time, to obtain useful fish oil and emulsified ingredients.Furthermore, it is possible to produce such fish sauce or its dried products, and processed products containing fish oil or emulsified ingredients. DETAILED DESCRIPTION OF THE INVENTION

[0027] As described above, the inventors have newly discovered that high-temperature autolysis of seafood or seafood processing waste in a yeast fermentation broth fermented with a pre-prepared Shirakami Kodama yeast or the like makes it possible to produce a fish sauce with a reduced unpleasant odor and a rich, umami-like taste, with a salt content of 8% or less and a total nitrogen % / salt % ratio of 0.20 or more. This discovery led to the completion of the present invention. At the same time, it became possible to obtain useful fish oil and emulsified ingredients. Furthermore, the inventors have newly discovered that excellent processed foods can be produced by blending the resulting fish sauce, its dried product, and fish oil and emulsified ingredients, leading to the completion of the present invention.

[0028] The method for producing fish sauce of the present invention is characterized in that fish and shellfish or fish and shellfish waste is autolyzed at a high temperature of 45°C or higher in a pre-prepared yeast fermentation liquid.

[0029] The fish sauce and dried product thereof of the present invention are characterized by having a salt content of 8% or less and a total nitrogen % / salt % ratio of 0.20 or more.

[0030] The aforementioned yeast fermentation liquid of the present invention is characterized by using Shirakami Kodama yeast.

[0031] The fish oil and emulsifying component of the present invention are characterized by being produced during the production of the above-mentioned fish sauce.

[0032] The processed product of the present invention is characterized by being blended with the above-mentioned fish sauce, its dried product, fish oil or emulsified component. [Example]

[0033] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to these examples.

[0034] (Example 1) Fish sauce made from whole sardines 200g of glucose, 1.5g of peptone, and 0.75g of yeast extract were dissolved in 1000ml of water, and 15g of dried Shirakami Kodama yeast powder was added to this, and the mixture was fermented at 25°C for 20 days. 1173g of whole sardines were then added to the fermented liquid, which was heated at 45°C for 48 hours with occasional stirring, and then further heated at 55°C for 72 hours to allow autolysis. Any bones that had not decomposed during heating were removed, and a mixture of fish sauce, emulsified ingredients, and oils and fats was obtained, which was then left to stand at room temperature for 7 days.

[0035] Whole fish were treated at 45°C for 48 hours, revealing the presence of undigested material and the need for further heat treatment. It was suggested that chopping the fish was necessary to shorten the processing time. Despite the absence of salt, no microbial contamination was observed during the 12 days from the addition of the fish to the separation, making the product safe. Furthermore, the deodorizing effect of the fermentation liquid was exhibited, resulting in unnoticeable fishy or autolyzed odors during autolysis. Upon standing, the autolyzed material separated into an oil layer, a middle layer, and a fish sauce layer. The middle layer did not separate even after centrifugation, suggesting it is a highly emulsifiable component. The separated fish sauce was a yellowish-brown liquid with a strong umami flavor and no distinctive fish sauce odor. It contained 1.25% total nitrogen and 0.31% salt, with a total nitrogen / salt ratio of 4.03. For long-term storage at room temperature, salt was added to the fish sauce to achieve an 8% salt content, and the fish sauce was monitored for 60 days at 30°C, but no microbial contamination was detected.

[0036] (Example 2) Fish sauce made from Thai waste 770 ml of 10% glucose aqueous solution was mixed with 10 g of Shirakami Kodama yeast dry powder and fermented at 20°C for 30 days, then heated at 65°C for 2 hours to kill the yeast. 732 g of sea bream processing by-products, including innards, were added to the fermented liquid, which was then kept at 45°C for 6 days with occasional stirring to allow autolysis. Any bones that had not decomposed during heating were removed, and the liquid was left to stand at room temperature for 7 days.

[0037] After standing, the autolyzed product separated into three layers: an oil layer, an emulsified layer, and a fish sauce layer. The fish sauce was yellowish-brown in color and had a delicious flavor. Its total nitrogen content was 0.78%, its salt content was 3.25%, and its total nitrogen / salt ratio was 0.24. This three-layer state was stored at 20°C for six months, but no oxidation of the oil layer or microbial contamination of the fish sauce layer was observed. The high salt content was thought to be due to salting during fish processing.

[0038] (Example 3) Fish sauce made from sardine waste 22.5g of fresh Shirakami Kodama yeast was suspended in a sugar solution made by dissolving 75g of glucose in 500ml of water, and fermented at 30°C for 7 days. 1194g of frozen by-products, including organs, discarded from canned sardines were mixed with this fermented liquid, and autolyzed at 45°C for 24 hours with occasional stirring, then at 55°C for 48 hours, with undecomposed bones being removed during heating. 75g of glucose and 7.5g of dried Shirakami Kodama yeast powder were added to this autolyzed liquid, and it was re-fermented at 30°C for 48 hours, and then left to stand at room temperature for 7 days.

[0039] The autolysate that was left to stand separated into three layers: an oil layer, an emulsified layer, and a fish sauce layer, as in Examples 1 and 2. Re-fermentation with yeast after autolysis was performed in order to reduce the odor of the fish sauce, and it was confirmed that the odor of the obtained fish sauce was reduced compared to Examples 1 and 2. This fish sauce was yellowish-brown in colour and had a strong umami flavour, as in the previous examples, with a total nitrogen content of 1.37%, a salt content of 0.41%, and a total nitrogen % / salt % ratio of 3.34.

[0040] (Example 4) Fish sauce made from bonito waste 9 kg of glucose and 1.5 kg of Shirakami Kodama yeast dry powder were added to 100 liters of water and fermented for 20 hours at a liquid temperature of 40°C to prepare a fermented liquid for autolysis. 160 kg of by-products, including the internal organs generated during the production of bonito fillets, were added to this 40°C fermented liquid and autolyzed for 40 hours at 55°C, after which the liquid was heated to 65°C or higher for sterilization and left to stand for 7 days.

[0041] After leaving the autolyzed liquor for 7 days, the upper oil and fat layer and the emulsified layer were separated, and undecomposed bones were removed to obtain bonito fish sauce. This bonito fish sauce lacked the distinctive fish sauce odor but retained the bonito odor. It was a yellowish-brown fish sauce with a strong umami flavor. Its Brix was 12.7, pH 6.31, total nitrogen content was 0.895%, salt content was 2.40%, and the total nitrogen % / salt % ratio was 0.373. Most of this salt was thought to be derived from salt sprinkled on the raw bonito during freezing. The autolyzed liquor, separated into three layers, showed no microbial contamination or oxidation of the oil even when stored at room temperature for 6 months.

[0042] (Example 5) Fish sauce made from squid A yeast fermentation liquid was prepared by adding 320g of glucose and 30g of Shirakami Kodama yeast dry powder to 2000ml of water and fermenting at 40°C for 30 hours. 77g of this yeast fermentation liquid was mixed with 57.7g of squid guts and 115.4g of jumbo squid fillets and digested at 55°C for 20 hours. After that, it was sterilized at 85°C and centrifuged to obtain a clear squid fish sauce.

[0043] The obtained squid fish sauce was brown in color, had a strong umami flavor, and had little odor. The total nitrogen content was 1.212%, the salt content was 0.55%, and the total nitrogen % / salt % was 2.203.

[0044] (Example 6) Fish sauce made from krill 150 g of krill was added to 76 g of the yeast fermentation liquid prepared in Example 5, digested at 55°C for 20 hours, then sterilized at 85°C, and centrifuged to obtain clear krill fish sauce.

[0045] The krill fish sauce obtained was yellow, tasty, and had a low odor. The total nitrogen content was 0.568%, the salt content was 0.23%, and the total nitrogen % / salt % was 2.407.

[0046] (Example 7) Prototype of dressing To 150 g of the mixture of the oil layer and the emulsified layer separated in Example 4, 50 g of bonito fish sauce and 30 g of brewed vinegar were added, and the mixture was mixed and emulsified in a blender to prepare a fish sauce dressing.

[0047] The prepared fish sauce dressing was a good dressing with a savory and oily taste, with a very low fish sauce odor, and no deterioration in quality such as microbial contamination was observed during a 60-day storage test at 30°C. [Industrial Applicability]

[0048] According to the present invention, by subjecting seafood or seafood processing waste to high-temperature autolysis in a short period of time in a yeast fermentation liquid fermented with a pre-prepared Shirakami Kodama yeast or the like, it is possible to produce fish sauce with a reduced unpleasant odor, a salt content of 8% or less, a total nitrogen % / salt % ratio of 0.20 or more, and a rich flavor, and at the same time, it is possible to obtain useful fish oil and emulsified ingredients.Furthermore, it is possible to produce such fish sauce or its dried products, and processed products containing fish oil or emulsified ingredients.

Claims

1. A method for producing fish sauce, characterized by subjecting fish and shellfish or fish and shellfish waste to autolysis at a high temperature of 45°C or higher in a pre-prepared yeast fermentation liquid.

2. 2. The fish sauce and its dried product according to claim 1, characterized in that the salt content is 8% or less and the value of total nitrogen % / salt % is 0.20 or more.

3. A method for producing fish sauce, wherein the yeast according to claim 1 is Shirakami Kodama yeast.

4. Fish oil and emulsified components produced during the production of the fish sauce according to claim 1.

5. A processed product characterized by being blended with the fish sauce or its dried product, fish oil or emulsified component according to claims 2 and 4.