A process for fermented dried fish and a technology for the development of fermentation agents

Abstract

The present invention provides a technology for fermented dried fish and the development of fermenting agents. A mixed fermentation preparation including Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis is used to perform mixed fermentation on dried fish. By controlling the salt content in the dried fish and the proportion relationship of the bacterial flora in the mixed fermentation preparation, the fermentation process is optimized, so as to obtain dried fish that is more fragrant and fresh, has no fishy smell, and has a softer, more glutinous and more delicate taste. In particular, the salt content of the product is reduced, and the contents of flavor substances such as 5 - hexyldihydro - 2(3H) - furanone, 3 - heptyldihydro - 5 - methyl - 2(3H) - furanone, nonanal, hexadecanal, and umami substances such as glutamic acid and aspartic acid are significantly increased, making the dried fish more popular among consumers.

Description

Technical Field

[0001] The present invention belongs to the field of aquatic food processing, and particularly relates to a fermented fish jerky process and a development technology of a fermenting agent. Background Art

[0002] Fish jerky, a deep-processed aquatic product of freshwater fish, is prepared by salting freshwater fish with salt and then flavoring or marinating with seasonings. Fish jerky has a good appearance, strong chewiness and good taste, and is deeply loved by people in the areas of Jiangsu and Zhejiang. However, the existing fish jerky has problems such as insufficient fish meat fragrance and umami, fishy smell, and relatively hard texture, which are difficult to meet the needs of some consumers.

[0003] Lactic acid bacteria are a general term for Gram-positive bacteria that can ferment sugars to produce lactic acid. It is often used as the starter culture of fermented foods, giving products a unique fermented flavor. Lactic acid bacteria are widely used in fermented dairy products, vegetable products and meat products. It can not only improve the food flavor, but also inhibit spoilage bacteria and pathogenic bacteria in food, thereby extending the food shelf life. Some research reports point out that this is mainly because lactic acid bacteria can produce antibacterial substances, such as organic acids and bacteriocins, through competitive action in food. Mixed lactic acid bacteria fermentation makes use of the synergistic effect between different bacterial populations to be closer to the original ecology. The lactic acid bacteria fermentation technology is widely used in the fermentation of dairy products and starches. However, at present, the application of lactic acid bacteria in low-salt fish products is not extensive.

[0004] In order to solve the problems of high salt content, insufficient fish meat fragrance and umami in the existing fish jerky, it is urgent to find a method for preparing fish jerky that can significantly improve the fish meat fragrance and umami, has a better flavor and a better taste. Summary of the Invention

[0005] To solve the above problems, the present invention provides a low-salt fermentation process for fish jerky and a development technology of a fermenting agent. A mixed fermentation preparation including Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis is prepared to carry out mixed fermentation on fish jerky, and by controlling the salt content in the fish jerky, controlling the proportion relationship of the bacterial populations in the mixed fermentation preparation, and optimizing the fermentation process, fish jerky that is more fragrant, has no fishy smell, has a softer, waxy and more delicate texture is prepared. In particular, the contents of the flavor substances 5-hexyldihydro-2(3H)-furanone, 3-heptyldihydro-5-methyl-2(3H)-furanone, nonanal, hexadecanal, and the umami substances glutamic acid, aspartic acid, etc. are all significantly increased, making the fish jerky more popular among consumers.

[0006] The present invention ferments dried fish with a mixed fermentation preparation, and the mixed fermentation preparation contains various lactic acid bacteria. The lactic acid bacteria are used to ferment dried fish, enabling the lactic acid bacteria to metabolize carbohydrate substances to produce a large amount of substances such as lactic acid and acetic acid. These metabolites can effectively reduce the fishy smell of fish products. The lactic acid bacteria can also produce a fermented fragrance through fermentation, endowing the product with a unique fermented flavor. It can produce organic acids from carbohydrates. These organic acids such as citric acid, malic acid, acetic acid, etc. not only have their own flavors but also react with alcohol substances in fish meat to generate esters with aromatic odors. The lactic acid bacteria can also produce a large amount of amino acids and polypeptides through the combined action of their own proteases and endogenous enzymes in fish meat. Moreover, the lactic acid bacteria can metabolize and degrade fatty acids to produce short-chain fatty acids, thereby generating a special flavor. Fish meat is rich in nutrients such as protein and unsaturated fatty acids and is prone to spoilage due to microbial contamination. Moreover, the lactic acid bacteria can effectively extend the shelf life of fish meat products.

[0007] Through a large amount of research, the present invention has specially formulated a mixed fermentation preparation formula for dried fish. Fermenting dried fish with this mixed fermentation preparation can significantly improve the fragrance and umami substances in the dried fish and make the fish meat of the dried fish more tender and glutinous, with a particularly good taste.

[0008] On the one hand, the present invention provides a mixed fermentation preparation for dried fish, and the mixed fermentation preparation includes Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus, and Bifidobacterium animalis subsp. lactis.

[0009] Research has shown that using a variety of bacteria for mixed fermentation has a more significant effect on improving the fresh fragrance and taste of dried fish compared with single lactic acid bacteria fermentation. It can also reduce the fishy smell, making the fish meat taste more delicate and more tender and glutinous.

[0010] Further, in the mixed fermentation preparation, the volume ratio of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus, and Bifidobacterium animalis subsp. lactis is 1:1:1:2; the bacterial liquid concentration of the mixed fermentation preparation is 10 8 ~10 9 cfu / mL.

[0011] Among the five bacteria of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus, and Bifidobacterium animalis subsp. lactis, the effect of Bifidobacterium animalis subsp. lactis is particularly obvious. Moreover, in the mixed fermentation preparation, when the content of Bifidobacterium animalis subsp. lactis is higher than other bacteria, the five bacteria have a better synergistic effect when fermenting dried fish, the prepared dried fish has a better flavor, the content of fragrance substances and umami substances is higher, and the taste is more fragrant and glutinous.

[0012] On the other hand, the present invention provides a preparation method for dried fish, which mainly includes the following steps:

[0013] (1) Prepare dried fish;

[0014] (2) Lightly bleach the dried fish;

[0015] (3) Inoculate with the mixed fermentation preparation as described in claim 1 or 2 and carry out fermentation.

[0016] Further, the light bleaching described in step (2) is as follows: Lightly bleach and desalt the dried fish with water for 1 - 2 h, then bake at 40 °C. After baking, the weight of the dried fish is 1.1 - 1.2 times the original weight.

[0017] Light bleaching can reduce the salt content in the dried fish, keep the salt content in the dried fish within the range of 1 - 5%, which is beneficial to the smooth progress of mixed fermentation.

[0018] Further, the inoculation amount of the mixed fermentation preparation described in step (3) is 10 - 20 mL / 100 g of dried fish, and the inoculation method is spraying or tumbling.

[0019] Further, the fermentation conditions described in step (3) are: fermentation temperature 20 °C, sealed fermentation for 24 h.

[0020] Further, the preparation method of the dried fish described in step (1) is: Take fresh - water fish, scale it and then slaughter it, wash it, pickle it with 15% - 20% of the fish body mass of salt for more than 12 h; wash it with running water, drain and dry it to control the water content at 35%;

[0021] Further, the drying temperature is 40 °C.

[0022] The salt content in the dried fish prepared by the present invention (the salt content is 7 - 10%). After light bleaching, the salt content is 1 - 5%. While preserving freshness and preventing spoilage, it can also provide better fermentation conditions for the mixed fermentation preparation, remove fishy smell, enhance the fresh fragrance, make the taste more delicate, and further improve the fresh fragrance and taste of the dried fish after mixed fermentation.

[0023] On the other hand, the present invention provides a preparation method of the above - mentioned mixed fermentation preparation, which mainly includes the following steps:

[0024] (Ⅰ) Activate Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis respectively;

[0025] (Ⅱ) Domestication - culture the activated bacterial liquids of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis respectively to obtain bacterial liquids of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis with a bacterial concentration of 10 8 ~10 9 cfu / mL;

[0026] (III) Mix the bacterial suspensions of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium animalis subsp. lactis in a volume ratio of 1:1:1:2 to obtain a mixed fermentation preparation.

[0027] Furthermore, the activated medium in step (I) is MRS medium; the composition of the domestication medium in step (II) is: 50% MRS medium and 50% fish broth.

[0028] On the other hand, the present invention provides the use of a mixed fermentation preparation for the preparation of a preparation for increasing the content of flavor substances and / or umami substances in dried fish. The mixed fermentation preparation includes Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium animalis subsp. lactis. The flavor substances include one or more of 5-hexyldihydro-2(3H)-furanone, 3-heptyldihydro-5-methyl-2(3H)-furanone, nonanal, and hexadecanal. The umami substances include glutamic acid and / or aspartic acid.

[0029] Furthermore, in the mixed fermentation preparation, the volume ratio of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium animalis subsp. lactis is 1:1:1:2; the bacterial suspension concentration of the mixed fermentation preparation is 10 8 ~10 9 cfu / mL.

[0030] The beneficial effects of the present invention are:

[0031] (1) The dried fish is mixed-fermented by Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium animalis subsp. lactis, which significantly improves the fresh flavor of the dried fish, makes the fish meat no longer hard, and tastes more fragrant and glutinous.

[0032] (2) By increasing the content of Bifidobacterium animalis subsp. lactis in the mixed fermentation preparation, the synergistic fermentation effect of the five bacteria is further improved, and the contents of the flavor substances 5-hexyldihydro-2(3H)-furanone, 3-heptyldihydro-5-methyl-2(3H)-furanone, nonanal, and hexadecanal, and the umami substances glutamic acid and aspartic acid in the dried fish are significantly increased, and the taste is better.

[0033] (3) After light bleaching, the salt content of the dried fish is 1-5%. While preserving freshness and preventing spoilage, it can also provide better fermentation conditions for the mixed fermentation preparation, remove fishy smell, improve fresh flavor, make the taste more delicate, and further improve the fresh flavor and taste of the dried fish after mixed fermentation.

[0034] (4) Optimize the inoculation amount and fermentation conditions of the mixed fermentation to further improve the fermentation effect. Description of the Drawings

[0035] Figure 1 It is the gas chromatography detection spectrum of the dried fish prepared by mixed fermentation in Example 6;

[0036] Figure 2 It is the gas chromatography detection chromatogram of the unfermented dried fish in Example 6. Detailed implementation manners

[0037] The present invention will be further described in detail below in conjunction with embodiments. It should be noted that the following embodiments are intended to facilitate the understanding of the present invention and do not impose any limitation on it. The reagents used in this embodiment are all known products and are obtained by purchasing commercially available products.

[0038] Preparation of mixed fermented dried fish in Example 1

[0039] The preparation method of the mixed fermented dried fish provided in this embodiment includes the following steps:

[0040] (1) Preparation of dried fish:

[0041] Take one grass carp, a freshwater fish. After scaling, it is slaughtered, washed, and pickled with 20% of the fish body mass of salt for more than 12 hours; then it is washed with running water to remove residues and surface stains, and after being washed, it is drained of water; the drained fish is dried at 40 °C to control its moisture content at about 35%; the dried fish is cut into blocks with a side length of about 5 cm, and the salt content is about 10%.

[0042] (2) Light bleaching of dried fish:

[0043] Take the dried fish for light bleaching for 1 hour, and the ratio of raw material to water is 1:15, and the water is changed 2 times during the process. After the surface water of the light-bleached dried fish is drained, it is placed in a constant temperature drying oven at 40 °C and dried to 1.1 - 1.2 times the raw material of the dried fish before light bleaching. The salt content in the dried fish after light bleaching and drying is about 2%.

[0044] (3) Inoculate with a mixed fermentation preparation for fermentation:

[0045] a. Preparation of the mixed fermentation preparation:

[0046] Respectively take Bifidobacterium powder (purchased from China Center for Industrial Culture Collection, No. 21711), Lactobacillus acidophilus powder (purchased from China Center for Industrial Culture Collection, No. 20244), Lactobacillus casei powder (purchased from China Center for Industrial Culture Collection, No. 20241), Streptococcus thermophilus powder (purchased from Mufan Biotech Co., Ltd., No. MF-001031) and Bifidobacterium lactis powder (purchased from Mufan Biotech Co., Ltd., No. MF-001040) and inoculate them into MRS medium (purchased from Qingdao Haibo Co., Ltd., model HB0384-1), and the inoculation amount is 5%, and cultured overnight at 30 °C;

[0047] Respectively take the activated bacterial solutions of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis and inoculate them into the domestication medium (50% MRS medium, 50% fish broth) for domestication culture. The inoculation amount is 10%, and culture at 30 °C for 24 h to obtain bacterial solutions of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis with a bacterial concentration of 10 8 ~10 9 cfu / mL;

[0048] Mix the bacterial solutions of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis in a volume ratio of 1:1:1:2 to prepare a mixed fermentation preparation.

[0049] b. Mixed fermentation

[0050] Inoculate the mixed fermentation preparation into the light bleached and dried fish. The inoculation amount is 15 mL / 100 g of fish, and the inoculation method is spraying or tumbling, and stir to mix evenly. At 20 °C, seal and ferment for 24 h. Put the fermented fish into a constant temperature drying oven and dry at 40 °C to the original weight before light bleaching. Obtain the fermented fish product.

[0051] Example 2 Influence of different strains of bacteria on the preparation of dried fish

[0052] In this example, dried fish was prepared according to the method provided in Example 1. During fermentation, different strains of bacteria were used respectively (the strains of bacteria used are shown in Table 1, and when the bacterial solutions are combined, they are all mixed in equal volume). The inoculation amount is 15 mL / 100 g of fish, and the bacterial concentration is 10 8 ~10 9 cfu / mL, inoculate the fish and ferment. Detect the contents of flavor substances 5-hexyldihydro-2(3H)-furanone (peach aroma), 3-heptyldihydro-5-methyl-2(3H)-furanone (onion and garlic-like aroma), nonanal (wax aroma, fatty aroma), hexadecanal (flower and wax aroma), and umami substances glutamate and aspartic acid in the prepared dried fish, as well as the fishy smell and taste of the dried fish. The content of flavor substances was detected by gas chromatography-mass spectrometry, and the content of umami substances was reflected by the content of free amino acids; the fishy smell and taste were comprehensively evaluated according to the taste of 30 volunteers to investigate the influence of different fermentation strains of bacteria on the flavor substances, umami substances and taste of the prepared dried fish. The results are shown in Table 1.

[0053] Table 1. Influence of different fermentation strains of bacteria on the preparation of dried fish

[0054]

[0055] As can be seen from Table 1, when a single type of bacterium is used for fermentation, it slightly improves the flavor substances and umami substances in the dried fish, but the effect is not obvious, resulting in a less fragrant and glutinous taste. Sometimes the taste is still a bit hard, and even the fishy smell of the dried fish cannot be completely removed. Among them, Bifidobacterium lactis has a slightly better effect on enhancing the flavor substances and umami substances in the dried fish than other bacteria, and the effect of removing the fishy smell is also slightly better.

[0056] When combined fermentation with several bacteria is carried out, it can be seen that when five bacteria are combined in equal volume for mixed fermentation, the effect on improving the quality of dried fish is particularly good, significantly better than the mixed fermentation effects after combining two, three or four types of bacteria. The reason should be that the five bacteria produce a synergistic effect during the mixed fermentation process, promoting the generation of more flavor and umami substances in the drunken fish meat. Among them, the content of 5-hexyldihydro-2(3H)-furanone reaches 2.25%, the content of 3-heptyldihydro-5-methyl-2(3H)-furanone reaches 3.87%, the content of nonanal reaches 1.01%, the content of hexadecanal reaches 4.03%, the content of glutamic acid reaches 12.6%, and the content of aspartic acid reaches 16.8%. The taste is the best, very fragrant and glutinous.

[0057] Example 3 Effect of the content of Bifidobacterium lactis in the mixed fermentation preparation on the preparation of dried fish

[0058] In this example, dried fish was prepared according to the method provided in Example 1. During the mixed fermentation, the proportional relationship of Bifidobacterium lactis in the mixed bacterial liquid was changed (see Table 2 for details). The inoculation amount was 15 mL / 100 g of dried fish, and the bacterial liquid concentration was 10 8 ~10 9 cfu / mL, and the dried fish was inoculated and mixed fermented respectively. The contents of flavor substances 5-hexyldihydro-2(3H)-furanone (peach aroma), 3-heptyldihydro-5-methyl-2(3H)-furanone (onion and garlic-like aroma), nonanal (waxy aroma, fatty aroma), hexadecanal (flower and wax aroma), and umami substances glutamic acid and aspartic acid in the prepared dried fish were detected, as well as the fishy smell and taste of the dried fish. The detection method was as in Example 2, and the results are shown in Table 2.

[0059] Table 2 Effect of the proportional relationship of Bifidobacterium lactis in the mixed bacterial liquid on the preparation of dried fish

[0060]

[0061] As can be seen from Table 2, the proportional relationship of Bifidobacterium lactis in the mixed bacterial liquid has a great influence on the quality of dried fish. When the ratio of Bifidobacterium : Lactobacillus acidophilus : Lactobacillus casei : Streptococcus thermophilus : Bifidobacterium lactis reaches 1:1:1:1:2, the contents of fragrant and umami substances in the drunken fish meat are the highest. The content of 5-hexyldihydro-2(3H)-furanone reaches 2.34%, the content of 3-heptyldihydro-5-methyl-2(3H)-furanone reaches 4.03%, the content of nonanal reaches 1.02%, the content of hexadecanal reaches 4.27%, the content of glutamic acid reaches 13.5%, and the content of aspartic acid reaches 17.7%. The taste is extremely good, without fishy smell, and very fragrant, glutinous and delicate. When the proportion of Bifidobacterium lactis is further increased, the contents of various fragrant and umami substances show a significant decrease, and the meat of the prepared dried fish is soft and the taste is poor. Therefore, it is necessary to control the ratio of Bifidobacterium : Lactobacillus acidophilus : Lactobacillus casei : Streptococcus thermophilus : Bifidobacterium lactis to 1:1:1:1:2 in order to prepare dried fish with better quality.

[0062] Example 4 Influence of Salt Content after Light Bleaching on the Preparation of Dried Fish

[0063] In this example, dried fish was prepared according to the method provided in Example 1, in which the salt content in the dried fish was controlled by controlling the light bleaching time. It was experimentally confirmed that after light bleaching for 30 min, the salt content in the dried fish was 6%; after light bleaching for 60 min, the salt content in the dried fish was 2%; after light bleaching for 90 min, the salt content in the dried fish was 0.1%; and after light bleaching, mixed fermentation was carried out separately. The contents of the fragrant substances 5-hexyldihydro-2(3H)-furanone (peach aroma), 3-heptyldihydro-5-methyl-2(3H)-furanone (onion and garlic aroma), nonanal (cured aroma, fatty aroma), hexadecanal (flower and wax aroma), and the umami substances glutamic acid and aspartic acid in the prepared dried fish were detected, as well as the fishy smell and taste of the dried fish. The detection method was as in Example 2, and the results are shown in Table 3.

[0064] Table 3 Influence of Salt Content after Light Bleaching on the Preparation of Dried Fish

[0065]

[0066] As can be seen from Table 3, the light bleaching time also has a very great influence on the quality of dried fish. The reason is that different light bleaching times result in different salt contents in the dried fish, and the salt content in the dried fish will directly affect the effect of mixed fermentation. When the light bleaching time is short (30 min), the salt content in the dried fish is relatively high at this time. When mixed fermentation is carried out at this time, it may have an inhibitory effect on the mixed fermentation, resulting in an insufficient content of fresh and fragrant substances in the dried fish; while when the light bleaching time is too long (90 min), the salt content in the dried fish is very low. When mixed fermentation is carried out at this time, the quality of the prepared dried fish also decreases. It can be seen that controlling the light bleaching time to maintain a certain salt content in the dried fish is also an important condition for preparing high-quality mixed fermentation dried fish, which can provide more suitable fermentation conditions for mixed fermentation, promote the increase of the content of fragrant substances and umami substances in the dried fish, and improve the taste. Therefore, the light bleaching time needs to be controlled at 60 min.

[0067] Example 5 Influence of the inoculation amount of the mixed fermentation preparation on the preparation of dried fish

[0068] In this example, dried fish was prepared according to the method provided in Example 1, and the inoculation amounts of the mixed fermentation preparation were respectively selected as 5, 10, 15, 20, 25 mL / 100 g of dried fish (as shown in Table 4). The contents of fragrant substances 5-hexyldihydro-2(3H)-furanone (peach aroma), 3-heptyldihydro-5-methyl-2(3H)-furanone (onion and garlic aroma), nonanal (wax aroma, fatty aroma), hexadecanal (flower and wax aroma), and umami substances glutamic acid and aspartic acid in the prepared dried fish were detected, as well as the fishy smell and taste of the dried fish. The detection method was as in Example 2, and the results are shown in Table 4.

[0069] Table 4 Influence of the inoculation amount of the mixed fermentation preparation on the preparation of dried fish

[0070]

[0071]

[0072] As can be seen from Table 4, only by selecting an appropriate inoculation amount can better quality of dried fish be obtained. When the inoculation amount of the mixed fermentation preparation is 10 - 20 mL / 100 g of dried fish, the content of fragrant and umami substances in the prepared dried fish is relatively high, the taste is fragrant, glutinous and delicate, and there is no fishy smell. The most preferred inoculation amount is 15 mL / 100 g of dried fish. At this time, the content of fragrant and umami substances in the prepared dried fish is the highest and the taste is the best.

[0073] Example 6 Comparison between the dried fish prepared by the present invention and the dried fish without mixed fermentation

[0074] In this example, dried fish was prepared according to the method provided in Example 1. Meanwhile, dried fish without mixed fermentation (the dried fish prepared in the first step of Example 1) was used as a control group for comparison. The content of volatile substances in the two kinds of dried fish was detected by gas chromatography, and the content of umami substances (reflected by the content of free amino acids) was detected. At the same time, the color, smell, taste, and state of the two groups of dried fish were scored, with a total of 10 points. A score above 8 was considered excellent (the color was white or slightly yellowish, with a strong fish fragrance and umami, the taste was fragrant and slightly sweet aftertaste, the texture was soft and glutinous, neither too hard nor too soft), a score above 6 was considered good, and a score below 6 was considered poor (the color was brownish, with an obvious fishy smell, a strong dried fish taste and a bitter aftertaste, the texture was dry or mushy). The results of gas chromatography detection are shown in Figure 1 , 2 ( Figure 1 is the detection chromatogram of dried fish prepared by mixed fermentation provided in Example 1, Figure 2 is the detection chromatogram of the dried fish in the control group), and Tables 5 and 6 (Table 5 is the detection result of dried fish prepared by mixed fermentation provided in Example 1, and Table 6 is the detection result of the dried fish in the control group); the detection results of umami substances, as well as the scoring results of color, smell, taste, and state are shown in Table 7.

[0075] Table 5. Chemical content of volatile substances in dried fish prepared by mixed fermentation

[0076]

[0077]

[0078] Table 6: Chemical content of volatile substances in the dried fish of the control group

[0079]

[0080]

[0081] Table 7. Detection results of umami substances in the two groups of dried fish

[0082]

[0083] It can be seen from Figure 1 , Figure 2 and Tables 5 and 6 that the dried fish prepared by mixed fermentation provided by the present invention has produced a large number of volatile flavor substances on the basis of the original dried fish (control group), making the dried fish have a strong fragrance and a particularly good taste. It can be seen from Table 7 that the dried fish prepared by mixed fermentation provided by the present invention has a significantly increased content of umami substances, a bright yellow color, a strong fish umami, a slightly sweet aftertaste, a soft and glutinous texture, neither dry nor firewood, and the quality has been greatly improved, and it will be loved by the majority of consumers.

[0084] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A mixed fermentation preparation for dried fish, characterized in that, It is composed of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis; the Bifidobacterium is purchased from the China Center for Industrial Culture Collection, with the number 21711; the Lactobacillus acidophilus is purchased from the China Center for Industrial Culture Collection, with the number 20244; the Lactobacillus casei is purchased from the China Center for Industrial Culture Collection, with the number 20241; the Streptococcus thermophilus is purchased from Mufan Biotech Co., Ltd., with the number MF-001031; the Bifidobacterium lactis is purchased from Mufan Biotech Co., Ltd., with the number MF-001040.

2. The mixed fermentation preparation according to claim 1, wherein In the mixed fermentation preparation, the volume ratio of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis is 1:1:1:1:2; the bacterial liquid concentration of the mixed fermentation preparation is 10 8 ~10 9 cfu / mL.

3. A method for preparing dried fish, characterized in that, It includes the following steps: (1) Prepare dried fish; (2) Lightly bleach the dried fish; (3) Inoculate with the mixed fermentation preparation as described in claim 1 or 2 and carry out fermentation.

4. The preparation method according to claim 3, characterized in that, The inoculation amount of the mixed fermentation preparation in step (3) is 10 - 20 mL / 100 g of dried fish, and the inoculation method is spraying or tumbling.

5. The preparation method according to claim 4, characterized in that, The fermentation conditions in step (3) are: fermentation temperature 20°C, sealed fermentation for 24 h.

6. The preparation method according to claim 5, characterized in that, The preparation method of the dried fish in step (1) is: take freshwater fish, scale and slaughter it, wash it, marinate it with 15% - 20% of the fish body mass of salt for more than 12 h; wash it with running water, drain and dry it to control the moisture content at 35%.

7. The preparation method of the mixed fermentation preparation according to claim 1 or 2, characterized in that, It includes the following steps: (Ⅰ) Activate Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis respectively; (Ⅱ) Domestication cultures were respectively carried out on the activated bacterial solutions of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium animalis subsp. lactis, and bacterial solutions of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium animalis subsp. lactis with a bacterial concentration of 10 8 ~10 9 cfu / mL were respectively obtained; (Ⅲ) Mix the bacterial solutions of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis according to the volume ratio of 1:1:1:1:2 to obtain a mixed fermentation preparation.

8. The method according to claim 7, wherein The activation medium in step (Ⅰ) is MRS medium; the composition of the domestication medium in step (Ⅱ) is: 50% MRS medium, 50% fish broth.

9. Use of a mixed fermentation preparation for preparing a preparation for increasing the content of flavor substances and / or umami substances in dried fish, characterized in that, The mixed fermentation preparation is composed of Bifidobacterium, Lactobacillus acidophilus, Lactobacillus casei, Streptococcus thermophilus and Bifidobacterium lactis. The Bifidobacterium is purchased from the China Center for Industrial Culture Collection, with the number 21711; the Lactobacillus acidophilus is purchased from the China Center for Industrial Culture Collection, with the number 20244; the Lactobacillus casei is purchased from the China Center for Industrial Culture Collection, with the number 20241; the Streptococcus thermophilus is purchased from Mufan Biotech Co., Ltd., with the number MF-001031; the Bifidobacterium lactis is purchased from Mufan Biotech Co., Ltd., with the number MF-001040; the flavor substances include one or more of 5-hexyldihydro-2(3H)-furanone, 3-heptyldihydro-5-methyl-2(3H)-furanone, nonanal, hexadecanal, and the umami substances include glutamic acid and / or aspartic acid.

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