Dried skipjack seasoning base material with glassy structure and preparation method of dried skipjack seasoning base material

Abstract

The invention relates to the technical field of aquatic product processing, in particular to a dried skipjack seasoning base material with a glassy structure and a preparation method of the dried skipjack seasoning base material. A liquid smoking method is adopted to replace a traditional smoking method, then special lactobacillus plantarum and staphylococcus xylosus are inoculated for anaerobic micro-fermentation, and finally a repeated drying-moisture regaining mode is adopted for drying, so that the problem that in the traditional dried skipjack production process, the production efficiency is high is solved; the invention discloses a novel dried skipjack seasoning base material which is safe, stable, short in production cycle, fine and compact in meat quality, and strong in delicate flavor, and has a glassy texture, aiming at overcoming the defects that a smoked drying method is harmful to product safety, too long in fermentation cycle, unstable in product quality and insufficient in delicate flavor in the prior art.

Description

Technical Field

[0001] The invention relates to the technical field of aquatic product processing, and in particular to a dried bonito seasoning base material with a glassy structure and a preparation method thereof. Background Art

[0002] Bonito is rich in nutrition, with huge production, and is abundant in the South my country Sea. It is also relatively cheap compared to other tunas. However, bonito has thick muscle fibers, loose meat, and poor taste, so it is not suitable for eating as sashimi. In addition, the meat has a strong fishy and sour taste, which leads to low consumer acceptance, low processing utilization rate, and difficulty in digesting the huge production of bonito. Therefore, it is urgent to develop bonito products that suit the taste of Chinese people.

[0003] Bonito is a traditional dried and smoked seasoning base. In addition to its pleasant umami and smoky flavor, bonito also exhibits a unique glassy state, which is convenient for slicing and eating with special tools. Traditionally, the processing technology of bonito seasoning base is made by boiling, smoking and drying, and spraying and fermenting. The process is cumbersome and usually takes about half a year. In addition, the traditional smoking and drying method by burning firewood is prone to produce substances such as polycyclic aromatic hydrocarbons, which will affect the environment and food safety. At the same time, the traditional spraying and fermentation process cycle is too long. This step usually takes about half a year, and the product quality is also easily affected by the natural open environment and unstable. According to research reports, the traditional fermentation of bonito is so time-consuming to prevent oil oxidation, improve storage stability, and evenly absorb the internal moisture of the product to extend the shelf life, but the effect of improving the umami taste of the product is not obvious. The traditional smoking and drying method also produces substances such as polycyclic aromatic hydrocarbons, which affect the environment and food safety. At the same time, the traditional fermentation process cycle is too long, and the product quality is also easily affected by the environment and unstable. Although the dried bonito seasoning that has been smoked and dried but not sprayed with mold and fermented can also be eaten directly, it has the disadvantage of insufficient freshness. Therefore, it is necessary to improve the production process of dried bonito and develop a dried bonito seasoning with stronger freshness on the basis of shortening the production time.

[0004] Patent CN107751851A discloses "A high-quality instant dried bonito fish and its production method", which comprises the following steps: cutting the bonito fish into strips and pieces, rolling and fumigating in a steamer, draining and performing variable temperature drying treatment, then smoking the bonito strips and pieces in a smoker for 8-12 minutes; inoculating lactic acid bacteria and lactobacillus, fermenting at 29-33°C for 2.0-2.5 hours, putting the fermented bonito strips or pieces into a seasoning liquid, and ultrasonically treating; finally, vacuum-sealing and packaging with high-temperature resistant soft canning packaging materials, sterilizing at high temperature, and cooling under reverse pressure to obtain the instant dried bonito fish of the present invention. This patent adopts the method of drying first and then smoking and fermenting to obtain ready-to-eat dried fish. The final product has a high moisture content and cannot be used as a seasoning. It also requires vacuum packaging, and the storage and transportation costs are high. In addition, the above method adopts the method of drying first and then smoking and fermenting. After variable temperature drying, the moisture content of the fish meat decreases, which may be in the microbial growth inhibition range, resulting in reduced metabolic activity of lactic acid bacteria and lactobacilli, and there is a risk of incomplete fermentation. The present invention adopts the method of fermentation first and then drying. The moisture content of the fish meat is high during the fermentation stage, which can provide a suitable growth environment for microorganisms, improve fermentation efficiency, and make metabolites accumulate faster, which is conducive to the production of flavor substances. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the current traditional fermentation method has a long cycle, and the fermentation process is carried out under natural conditions, the fermentation degree is difficult to distinguish, there are differences between product quality batches, and the product quality and safety cannot be guaranteed; and the unfermented dried bonito has the disadvantage of insufficient umami. Therefore, it is necessary to improve the production process of dried bonito and develop a dried bonito seasoning base with stronger umami on the basis of shortening the production time.

[0006] In view of the problems of the prior art, the present invention provides a dried bonito seasoning base with a glassy structure and a preparation method thereof. Liquid smoking is used to replace the traditional smoking method, and then special plant lactobacillus and xylose staphylococcus are inoculated for anaerobic micro-fermentation. Finally, repeated drying-rehumidification is used for drying. The shortcomings of the traditional dried bonito production process, such as the smoking and drying method endangering product safety, too long fermentation cycle, unstable product quality, and insufficient umami, are solved. A new dried bonito seasoning base with a safe and stable structure, a short production cycle, fine and firm meat, a glassy texture and strong umami is developed.

[0007] To achieve the above object, the present invention is implemented by the following technical scheme: A method for preparing a dried bonito seasoning base with a glassy structure, comprising the following steps: (1) Pretreatment of bonito meat; (2) diluting the smoke liquid to a volume ratio of 1.5% and adding edible salt in a mass volume ratio of 1.5%, and completely immersing the bonito meat block in the smoke liquid at 2-8°C for 12 hours to obtain liquid smoked bonito block; liquid smoking is an alternative method to traditional smoking, which is a smoking method in which smoke liquid is applied to the surface of food by immersion or direct spraying, which can not only provide a stable and safe smoked flavor for fish, but also improve product safety and production efficiency, and reduce environmental pollution and energy consumption; (3) Take out the liquid smoked bonito chunks, slowly rinse the residual smoked liquid on the surface of the fish meat with clean water and wipe it dry with absorbent paper; inoculate the mixed fermentation agent on the surface at a mass ratio of 1:50 to the liquid smoked bonito chunks for anaerobic micro-fermentation, control the fermentation temperature at 30°C, and ferment for 10 hours; anaerobic micro-fermentation can improve the bioavailability of nutrients in fish meat, and microorganisms produce flavor precursors by degrading proteins and fats in fish meat. These flavor precursors further react into flavor compounds such as alcohols, aldehydes, and ketones through fat degradation and Maillard reaction, thereby improving the flavor and taste of the food; (4) After 10 h of fermentation, the slightly fermented bonito is immediately steamed at 100 °C for 5-10 minutes to terminate the fermentation and cook the fish meat; (5) The cooked fish meat is placed in a hot air drying oven for drying. After drying for 8 to 12 hours, the fish meat is taken out and placed in a sealed container at 2-8°C for 8 to 12 hours for moisture recovery. After 8 to 12 hours of moisture recovery, the fish meat is taken out and hot air drying is continued for 8 to 12 hours. The drying-moisturizing process is repeated until the moisture content of the dried bonito is less than 20%, thus obtaining a dried bonito seasoning base with a glassy structure. In the initial stage of drying, the water migration rate inside the fish meat is greater than the surface evaporation rate, but as the drying process proceeds, the moisture content decreases and the fish meat surface shrinks, resulting in a decrease in drying efficiency. The moisture recovery process can help water molecules migrate from the inside of the fish meat to the surface, causing the moisture content to decrease exponentially during the drying process, which is crucial to the formation of a uniform glassy structure.

[0008] Furthermore, the fish meat pretreatment method in step (1) is as follows: the bonito meat thawed in running water is washed, beheaded, gutted, skinned, and the back muscle is cut into 4 × 4 × 3 cm 3 of fish meat.

[0009] Furthermore, the smoke liquid in step (2) is hawthorn kernel smoke flavoring II or American Red Arrow smoke liquid.

[0010] Furthermore, the effective viable count of the mixed fermentation agent in step (3) is 10 7 CFU / mL.

[0011] Furthermore, the mass ratio of Lactobacillus plantarum to Staphylococcus xylosus in the composite fermentation agent of step (3) is 1:1, wherein Lactobacillus plantarum has a preservation number of ATCC 8014; the Staphylococcus xylosus has a preservation number of ATCC 29971, and the above-mentioned strains used in the present invention are purchased from the Beijing Strain Collection Center. Lactobacillus plantarum can quickly produce lactic acid, reduce the pH value of the fermentation environment, inhibit the growth of spoilage bacteria and pathogenic bacteria, and improve the safety of the product. Staphylococcus xylosus can secrete protease and lipase to decompose macromolecular proteins and lipids in fish meat, produce flavor precursors, and promote the color formation of fermented fish and improve the product texture. The acid production of Lactobacillus plantarum provides a suitable weakly acidic environment for Staphylococcus xylosus, promoting the efficient expression of the latter's enzyme activity; and the protein hydrolyzate of Staphylococcus xylosus can serve as a nitrogen source for Lactobacillus plantarum, accelerating its growth and metabolism. The synergistic fermentation of Lactobacillus plantarum and Staphylococcus xylosus can complement each other and enhance their effectiveness, thereby jointly improving the product quality of micro-fermented dried bonito.

[0012] Furthermore, in step (5), the hot air drying temperature is 50°C.

[0013] Furthermore, the drying and rehumidification times in step (5) are the same.

[0014] A liquid smoked bonito block prepared by steps (1) to (2).

[0015] A dried bonito seasoning base material with a glassy structure prepared by the above steps.

[0016] The beneficial effects of the present invention are: (1) The processing method of the present invention takes a relatively short time throughout the entire process. The use of liquid smoking instead of traditional smoking can provide a unique smoked flavor while ensuring product safety. The micro-fermentation-drying process can shorten the production time and significantly improve the umami level of the dried bonito seasoning while stably forming a glassy structure.

[0017] (2) The dried bonito seasoning obtained by the present invention is further illustrated by the determination of safety indexes, flavor components, and flavor components. The dried bonito seasoning produced by the method of the present invention has extremely low volatile basic nitrogen and histamine contents, which meet national safety standards. The contents of umami amino acids and umami nucleotides and equivalent umami concentrations are significantly increased, and the volatile flavor components are increased, highlighting its key role as a seasoning. It can be seen that the production of dried bonito seasoning using the micro-fermentation-drying process can significantly shorten the processing time, better improve the umami and flavor quality, and has important practical significance for promoting the processing and utilization of bonito.

[0018] (3) Compared with traditional smoke drying, hot air drying can shorten the drying time and better control the temperature and humidity during the drying process, while reducing the harmful substances (such as polycyclic aromatic hydrocarbons) produced by long-term smoke drying, and produce products with stability and repeatability.

[0019] (4) In terms of enhancing the umami taste of dried bonito seasoning, the present invention can accelerate the fermentation process by screening and optimizing the fermentation bacteria and accurately controlling the fermentation conditions (temperature, humidity, pH value) while ensuring the flavor and safety of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a graph of the electronic tongue detection results of Examples 1-4.

[0021] Figure 2 1-4 is a graph showing the volatile flavor detection results of Examples 1-4.

[0022] Figure 3 It is a longitudinal section view of the products of Example 1 and Comparative Examples 1-4.

[0023] Figure 4 It is a graph showing the test results of the texture characteristics of Example 1 and Comparative Examples 1-4.

[0024] Figure 5 It is a diagram of the microstructure detection results of Example 1 and Comparative Examples 1-4.

[0025] Figure 6 It is the result diagram of protein secondary structure of Example 1 and Comparative Examples 1-4. DETAILED DESCRIPTION

[0026] The following description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0027] The experimental methods involved in the following examples, unless otherwise specified, are all conventional methods in the art, for example, reference can be made to the experimental manuals in the art, or the conditions recommended by the manufacturer's instructions. The experimental materials and reagents involved in the following examples, unless otherwise specified, can all be obtained from commercial sources.

[0028] Embodiment 1: (1) Wash, decapitate, gut and skin the thawed bonito meat in running water, and cut the back muscle into pieces. Dilute the liquid smoke (Hawthorn Smoked Flavoring No. II) to 1.5% (v / v) and add 1.5% (w / v) edible salt to it, and completely immerse the bonito meat pieces in the liquid smoke.

[0029] (2) Mix the fermentation agents (Lactobacillus plantarum and Staphylococcus xylosus) in equal proportions (1:1) and set the bacterial solution concentration to 10 7 CFU / mL. The composite fermentation agent was inoculated on the surface of the liquid smoked bonito block at a dosage of 2%, and micro-fermented at 30°C for 10 hours without oxygen.

[0030] (3) After fermentation for 10 hours, take out the fish immediately and steam it in a steamer at 100°C for 5 minutes to end the fermentation and cook the fish.

[0031] (4) The cooked fish meat is placed in a hot air drying oven and dried at a drying temperature of 50°C. After drying for 12 hours, the fish meat is taken out and sealed, and placed at 2-8°C for 12 hours to stabilize moisture recovery. After 12 hours of moisture recovery, the fish meat is taken out and placed in a 50°C hot air drying oven for another 12 hours. The drying-rehumidification process is repeated until the moisture content of the dried bonito is less than 20%.

[0032] (5) The prepared dried bonito seasoning is packaged and stored in a dry place.

[0033] Embodiment 2: (1) Wash, decapitate, gut and skin the thawed bonito meat in running water, and cut the back muscle into pieces. Dilute the liquid smoke (Hawthorn Smoked Flavoring No. II) to 1.5% (v / v) and add 1.5% (w / v) edible salt to it, and completely immerse the bonito meat pieces in the liquid smoke.

[0034] (2) Mix the fermentation agents (Pediococcus pentosaceus and Staphylococcus xylosus) in equal proportions (1:1) and set the bacterial solution concentration to 10 7 CFU / mL. The composite fermentation agent was inoculated on the surface of the liquid smoked bonito block at a dosage of 2%, and micro-fermented at 30°C for 10 hours without oxygen.

[0035] (3) After 10 hours of fermentation, take out the fish immediately and steam it in a steamer at 100°C for 5 minutes to end the fermentation and cook the fish.

[0036] (4) The cooked fish meat is placed in a hot air drying oven and dried at a drying temperature of 50°C. After drying for 12 hours, the fish meat is taken out and sealed, and placed at 2-8°C for 12 hours to stabilize moisture recovery. After 12 hours of moisture recovery, the fish meat is taken out and placed in a 50°C hot air drying oven for another 12 hours. The drying-rehumidification process is repeated until the moisture content of the dried bonito is less than 20%.

[0037] (5) The prepared dried bonito seasoning is packaged and stored in a dry place.

[0038] Embodiment 3: (1) Wash, decapitate, gut and skin the thawed bonito meat in running water, and cut the back muscle into pieces. Dilute the liquid smoke (Hawthorn Smoked Flavoring No. II) to 1.5% (v / v) and add 1.5% (w / v) edible salt to it, and completely immerse the bonito meat pieces in the liquid smoke.

[0039] (2) Mixed fermentation agents (Pediococcus pentosaceus and Staphylococcus carnosus) were prepared in equal proportions (1:1) with a uniform bacterial concentration of 107 CFU / mL. The mixed fermentation agent was inoculated on the surface of the liquid smoked bonito block at a dosage of 2% and micro-fermented at 30°C for 10 h without oxygen.

[0040] (3) After 10 hours of fermentation, take out the fish immediately and steam it in a steamer at 100°C for 5 minutes to end the fermentation and cook the fish.

[0041] (4) The cooked fish meat is placed in a hot air drying oven and dried at a temperature of 50°C. After drying for 12 hours, the fish meat is taken out and sealed, and placed at 2-8°C for 12 hours for stable moisture recovery. After 12 hours of moisture recovery, the fish meat is taken out and placed in a hot air drying oven at 50°C for another 12 hours. The drying-rehumidification process is repeated until the moisture content of the dried bonito is less than 20%.

[0042] (5) The prepared dried bonito seasoning is packaged and stored in a dry place.

[0043] Embodiment 4: (1) Wash, decapitate, gut and skin the thawed bonito meat in running water, and cut the back muscle into pieces. Dilute the liquid smoke (Hawthorn Smoked Flavoring No. II) to 1.5% (v / v) and add 1.5% (w / v) edible salt to it, and completely immerse the bonito meat pieces in the liquid smoke.

[0044] (2) Steam in a steamer at 100°C for 5 minutes to end fermentation and cook the fish.

[0045] (3) The cooked fish meat is placed in a hot air drying oven and dried at a temperature of 50°C. After drying for 12 hours, the fish meat is taken out and sealed, and placed at 2-8°C for 12 hours to stabilize moisture recovery. After 12 hours of moisture recovery, the fish meat is taken out and placed in a 50°C hot air drying oven for another 12 hours. The drying-rehumidification process is repeated until the moisture content of the dried bonito is less than 20%.

[0046] (4) The prepared dried bonito seasoning is packaged and stored in a dry place.

[0047] Comparative Example 1: The same as Example 1, except that the cooked fish meat obtained in Example 1 is not dried but directly stored at -20°C.

[0048] Comparative Example 2: The same as Example 1, except that the cooked fish obtained in Example 1 is placed in a food-grade hot air drying oven for drying at a drying temperature of 40°C, and the fish is taken out and sealed after drying for 12 hours, and placed at 2-8°C for stable rehumidification for 12 hours. The drying-rehumidification process is repeated as a whole until the moisture content of the dried bonito is less than 20%.

[0049] Comparative Example 3: The same as Example 1, except that the cooked fish meat obtained in Example 1 is placed in a food-grade hot air drying oven for drying at a drying temperature of 60° C. After drying for 12 hours, the fish meat is taken out, sealed, and placed at 2-8° C. for 12 hours for stable rehumidification. The drying-rehumidification process is repeated until the moisture content of the dried bonito is less than 20%.

[0050] Comparative Example 4: The same as Example 1, except that the cooked fish meat obtained in Example 1 is placed in a food-grade hot air drying oven for drying at a drying temperature of 50° C. without performing a rehumidification process until the moisture content of the dried bonito is less than 20%.

[0051] Effect verification: 1. Taste comparison: The dried bonito prepared in Example 1-4 was subjected to electronic tongue detection, and the method was as follows: The taste characteristics of dried bonito samples were detected using an electronic tongue system (TS-5000Z). The sample (5 g) was mixed with 250 mL of ultrapure water at 40°C for 30 min and the supernatant was collected by centrifugation. The electronic tongue sensor was immersed in the sample extract for 120 s to obtain the electrical signal. The results are shown in Figure 1 As shown, Example 1 shows a unique flavor modification advantage by using a compound fermentation agent of Lactobacillus plantarum and Staphylococcus xylosus. Compared with Examples 2-4, the dried bonito sample prepared in Example 1 has the strongest umami, sweetness and richness (i.e., umami aftertaste) and significantly reduced sourness and bitterness values, indicating that Lactobacillus plantarum can produce a synergistic effect with Staphylococcus xylosus, significantly improving the sweetness and umami persistence of dried bonito, and reducing the generation of undesirable flavors such as sourness.

[0052] 2. Comparison of volatile flavor components: The volatile flavor components of the dried bonito prepared in Examples 1-4 were detected as follows: 2 g of sample was accurately weighed, mixed with 3 mL of saturated NaCl solution, and 70 μL of 2,4,6-trimethylpyridine was added as an internal standard. The volatile flavor components were detected using a GC-MS system equipped with an HP-Innowax column (30 m × 0.25 mm, 0.25µm). The volatile compounds were identified using NIST 17 and Wiley standard libraries, and semi-quantitative analysis was performed based on the concentration of the internal standard and the peak area of ​​the target compound. The results are shown in Figure 2. Figure 2 As shown, compared with Examples 2-4, Example 1 has the highest types and contents of volatile flavor substances, and the synergistic fermentation of Lactobacillus plantarum and Staphylococcus xylosus can promote the production of volatile flavor compounds in dried bonito. The contents of benzaldehyde and acetophenone in Example 1 are the highest, both of which may be derived from the Strecker degradation of phenylalanine. The complementary strains in the synergistic fermentation accelerate the release and conversion of amino acid precursors, giving the dried bonito seasoning base a unique nutty aroma and sweetness. In addition, the increase in the content of 1-octen-3-ol and furan heterocyclic compounds in Example 1 gives the product a unique mushroom flavor and pleasant aroma such as baking aroma.

[0053] 3. Color comparison: The color of Example 1 and Comparative Examples 1-4 was compared as follows: The color difference of the product was measured using an UltraScan Pro1166 colorimeter. Color parameters, including brightness (L * )、Redness(a * ) and yellow-blueness (b * ). Each sample was measured three times. The results are shown in Figure 3 As shown in Table 1, compared with the product of Comparative Example 1 without drying treatment, the L * The value increased significantly after drying ( p < 0.05), which is because after drying, the surface protein of fish meat denatures due to heat to form a dense structure, which makes the surface smoother. This physical structure change can increase light reflection, resulting in brightness (L * ) is significantly improved. * Value and b * The value is the highest, indicating that the dried bonito obtained in Example 1 has the highest redness and yellowness values. After drying, the oxidation of myoglobin and the Maillard reaction are enhanced, and the thermal effect accelerates the conversion of Fe²⁺ in myoglobin to Fe³⁺, generating metmyoglobin, and the fish meat becomes red and bright, which is similar to Figure 3 The results are consistent with those of the longitudinal section view of the dried bonito product shown.

[0054] Table 1 Comparison of the colors of Example 1 and Comparative Examples 1-4: .

[0055] 4. Texture comparison: The textures of Example 1 and Comparative Examples 1-4 were compared as follows: The samples were cut into small cubes (1 × 1 × 1 cm 3 ), using a texture analyzer (SCIENTZ-12N) with a P / 50R probe. Two consecutive cycles were performed at a test speed of 1 mm / s at a deformation of 30% and a trigger force of 5 g The results are as follows Figure 4 As shown, compared with the comparative example 1 without drying process, the dried bonito obtained in the example 1 and comparative examples 2-4 have higher hardness, elasticity and chewiness. This is because after drying, the protein in the muscle cells of the fish meat undergoes condensation and denaturation, forming a highly cross-linked network structure, which inhibits the hydrolysis of myofibril protein, thereby increasing the mechanical strength of the muscle structure. Among them, the dried bonito obtained in the example 1 with a drying temperature of 50°C has the highest elasticity, which is convenient for making the high-hardness product into a thin slice form by cutting tools during consumption, thereby improving the palatability of the product. The dried bonito obtained in the comparative example 4 without the rehumidification process has too high hardness, which is attributed to the excessive hardening of the product caused by the rapid evaporation of water during the drying process.

[0056] 5. Microstructure: The textures of Example 1 and Comparative Examples 1-4 were compared as follows: The samples were cut into small cubes (0.5 × 0.2 × 0.2 cm 3 ), fixed with 2.5% glutaraldehyde at 4°C for 24 h. The myofibril microstructure of each sample was observed on longitudinal sections at 5000× and 10000× using a Hitachi 765 transmission electron microscope. Figure 5 As shown, the myofibril structure in the undried bonito product of Comparative Example 1 is clear and tightly arranged, and the bright bands, dark bands, Z lines, and M lines are complete and clear. In Comparative Examples 2 and 3, the myofibrils are obviously destroyed, the A band and M line are blurred, the Z line is broken, dislocated and twisted, and a small amount of Z line debris appears. And within a certain range, adjacent Z lines overlap and irregular deformation occurs. In the dried bonito obtained without the rehydration process in Comparative Example 4, most of the Z lines and M lines are misplaced, the myofibril structure becomes twisted and messy, the degree of Z line breakage is aggravated, and a large number of Z line debris and myofibril fragments appear. The transversely arranged thick and thin filaments in the fish myofibrils of Example 1 show obvious aggregation, close arrangement, increased regularity, and transverse contraction. The myofibril density increases significantly. This increase in myofibril density and diameter may be the reason why dried bonito has the highest elasticity and glassy texture.

[0057] 6. Protein secondary structure: The protein secondary structures of Example 1 and Comparative Examples 1-4 were compared as follows: The freeze-dried myofibrillar protein was ground into powder and Raman spectra were generated using a DXR Raman microscope. A semiconductor laser (λ = 532 nm) was used as the excitation source with a wavelength range of 400–3500 cm -1 The spectrum was captured in a wide range of wavelengths. -1 The phenylalanine band nearby was used as an internal standard to normalize the Raman spectrum. The secondary structure of the protein is shown in Figure 6 As shown, the protein secondary structure results show that compared with Comparative Example 1, the myofibrillar protein in the dried fish meat in Example 1 and Comparative Examples 2-4 is composed of β - Corner α -spiral, β - folding and random coil transitions, β - Angle stretching breaks the balance between electrostatic repulsion and hydrophobic interaction of proteins, and the structural compactness and conformational stability of proteins are increased. In Example 1, the ratio of α-helix and β-folded structure of myofibrillar protein is the highest, indicating that the protein aggregation degree is the highest, indicating that the drying temperature of 50°C can promote the formation of protein thermal aggregates and enhance the structural compactness and conformational stability of proteins.

[0058] In summary, by comparing the taste characteristics and volatile flavor compounds of dried bonito prepared by different composite fermentation agents, it was found that the use of Lactobacillus plantarum and Staphylococcus xylosus composite fermentation agents can not only significantly improve the umami and sweetness levels of dried bonito, reduce the sourness of the product, but also produce a large number of characteristic flavor compounds such as benzaldehyde, acetophenone and 1-octen-3-ol, giving the product unique nutty, mushroom and roasted aromas and other pleasant smells. The drying-rehumidification process at 50℃ can obtain dried bonito products with the best color and elastic texture. The increase in myofilament density and the enhancement of protein conformational stability promote the formation of a uniform glassy structure of dried bonito.

[0059] The various aspects, embodiments, and features of the present invention should be considered to be illustrative in all aspects and not limiting of the present invention, the scope of which is defined solely by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0060] In the preparation method of the present invention, the order of each step is not limited to the order listed. For those skilled in the art, without creative work, the order of each step is also within the protection scope of the present invention. In addition, two or more steps or actions can be performed simultaneously.

[0061] Finally, it should be noted that the specific embodiments described herein are merely examples of the present invention, and are not intended to limit the implementation methods of the present invention. A person skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described, or replace them in a similar manner. It is not necessary and impossible to provide all examples of all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the scope of protection of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A method for preparing a dried bonito seasoning base having a glassy structure, characterized in that The following steps are involved: (1) Pretreatment of bonito meat; (2) diluting the smoked liquid to a volume ratio of 1.5% and adding edible salt in a mass volume ratio of 1.5% thereto, and completely immersing the bonito meat pieces in the smoked liquid at 2-8° C. for 12 hours to obtain liquid smoked bonito meat pieces; (3) taking out the liquid smoked bonito block, slowly washing the residual smoked liquid on the surface of the fish meat with clean water and wiping it dry with absorbent paper; inoculating the composite fermentation agent on the surface of the fish meat in a mass ratio of the mixed fermentation agent to the liquid smoked bonito block of 1:50 for anaerobic micro-fermentation, controlling the fermentation temperature at 30° C. for 10 hours; (4) After fermentation for 10 hours, the slightly fermented bonito is immediately steamed at 100°C for 5-10 minutes to terminate the fermentation and cook the fish meat; (5) The cooked fish meat is placed in a hot air drying oven for drying. After drying for 8 to 12 hours, the fish meat is taken out and placed in a sealed container at 2-8°C for 8 to 12 hours for moisture recovery. After 8 to 12 hours of moisture recovery, the fish meat is taken out and hot air drying is continued for another 8 to 12 hours. The drying-moisturizing process is repeated until the moisture content of the dried bonito is less than 20%, thereby obtaining a dried bonito seasoning base with a glassy structure.

2. The preparation method according to claim 1, characterized in that: The fish meat pretreatment method in step (1) is as follows: the thawed bonito fish meat is washed, beheaded, gutted, skinned, and the back muscle is cut into 4 × 4 × 3 cm 3 of fish meat.

3. The preparation method according to claim 1, characterized in that: The effective viable bacteria count of the mixed fermentation agent in step (3) is 10 7 CFU / mL.

4. The preparation method according to claim 1, characterized in that: The mass ratio of Lactobacillus plantarum to Staphylococcus xylosus in the composite fermentation agent of step (3) is 1:1, wherein the Lactobacillus plantarum has a preservation number of ATCC 8014 and the Staphylococcus xylosus has a preservation number of ATCC 29971.

5. The preparation method according to claim 1, characterized in that: The hot air drying temperature in step (5) is 50°C.

6. The preparation method according to claim 1, characterized in that: The drying and rehumidification times in step (5) are the same.

7. A dried bonito seasoning base having a glassy structure prepared by the preparation method according to claim 1.

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